Abstract

We examine the contributions of preneural mechanisms, i.e., the optics of the eye and the aperture, spacing, and efficiency of foveal cones, to poor spatial and chromatic vision in human neonates. We do so by comparing the performances of ideal observers incorporating the characteristics of the optics and the foveal cones of adults and neonates. Our analyses show that many, but not all, of the differences between neonatal and adult contrast sensitivities and grating acuities can be explained by age-related changes in these factors. The analyses also predict differing growth curves for vernier and grating acuities. Finally, we demonstrate that preneural mechanisms constrain chromatic discrimination in human neonates and that discrimination failures may reflect poor visual efficiency rather than immature chromatic mechanisms per se.

© 1988 Optical Society of America

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  1. D. S. Jacobs, C. Blakemore, “Factors limiting the postnatal development of visual acuity in the monkey,” Vision Res. 28, 947–958 (1988).
    [CrossRef] [PubMed]
  2. H. R. Wilson, “Development of spatiotemporal mechanisms in infant vision,” Vision Res. 28, 611–628 (1988).
    [CrossRef] [PubMed]
  3. G. Bronson, “The postnatal growth of visual capacity,” Child Dev. 45, 873–890 (1974); P. Salapatek, “Pattern perception in early infancy,” in Infant Perception: From Sensation to Cognition, L. B. Cohen, P. Salapatek, eds. (Academic, New York, 1975), pp. 133–248.
    [CrossRef] [PubMed]
  4. A. M. Brown, V. Dobson, J. Maier, “Visual acuity of human infants at scotopic, mesopic, and photopic luminances,” Vision Res. 27, 1845–1858 (1987).
    [CrossRef]
  5. S. Shimojo, R. Held, “Vernier acuity is less than grating acuity in 2- and 3-month-olds,” Vision Res. 27, 77–86 (1987).
    [CrossRef] [PubMed]
  6. D. Y. Teller, M. H. Bornstein, “Infant color vision,” in Handbook of Infant Perception, P. Salapatek, L. B. Cohen, eds. (Academic, New York, 1978), pp. 185–236.
  7. W. S. Geisler, “Physical limits of acuity and hyperacuity,” J. Opt. Soc. Am. A 1, 775–782 (1984).
    [CrossRef] [PubMed]
  8. W. S. Geisler, “Sequential ideal-observer analysis of visual discriminations,” Psychol. Rev. (to be published).
  9. D. G. Pelli, “Uncertainty explains many aspects of human contrast detection and discrimination,” J. Opt. Soc. Am. A 2, 1508–1532 (1985); A. B. Watson, H. B. Barlow, J. G. Robson, “What does the eye see best?” Nature 31, 419–422 (1983).
    [CrossRef] [PubMed]
  10. H. B. Barlow, “Temporal and spatial summation in human vision at different background intensities,” J. Physiol. 141, 337–350 (1958).
  11. A. Rose, “The relative sensitivities of television pick-up tubes, photographic film, and the human eye,” Proc. IRE 30, 293–300 (1942).
    [CrossRef]
  12. Most of the growth of the eye occurs in the first year. Axial length, for instance, is 16–17 mm at birth, 20–21 mm at 1 year, and 23–25 mm in adolescence and adulthood [see Ref. 13; S. Hirano, Y. Yamamoto, H. Takayama, Y. Sugata, K. Matsuo, “Ultrasonic observations of eyes in premature babies. Part 6: growth curves of ocular axial length and its components,” Acta Soc. Ophthalmol. Jpn. 83, 1679–1693 (1979)]. Image magnification is proportional to posterior nodal distance [A. G. Bennett, J. L. Francis, “Aberrations of optical images,” in The Eye, H. Davson, ed. (Academic, New York, 1962)], and so calculations of age-related changes in magnification require estimates of the nodal distance at different ages. The only schematic eyes described for the newborn [J. M. Enoch, R. D. Hamer, “Image size correction of the unilateral aphakic infant,” Ophthalmol. Pediatr. Genet. 2, 153–165 (1983); W. Lotmar, “A theoretical model for the eye of new-born infants,” Albrecht von Graefes Archiv. Klin. Exp. Ophthalmol. 198, 179–185 (1976)] have posterior nodal distances of 10.3–12.0 mm, roughly 2/3 of the adult distance. For a given target in space, then, retinal image size in the eye of the newborn infant should be 2/3 of that in the mature eye. Stated another way, a 1-deg target should subtend 204 μ m on the retina of a newborn infant and 298 μ m on the retina of an adult.
    [CrossRef]
  13. J. S. Larsen, “The sagittal growth of the eye. IV. Ultrasonic measurement of the axial length of the eye from birth to puberty,” Acta Ophthalmol. 49, 873–886 (1971).
    [CrossRef]
  14. P. Salapatek, M. S. Banks, “Infant sensory assessment: vision,” in Communicative and Cognitive Abilities: Early Behavioral Assessment, F. D. Minifie, L. L. Lloyd, eds. (University Park, Baltimore, Md., 1978).
  15. S. Stenstrom, “Investigation of the variation and the correlation of the optical elements of human eyes,” Am. J. Optom. 25, 5 (1946).
  16. C. Yuodelis, A. Hendrickson, “A qualitative and quantitative analysis of the human fovea during development,” Vision Res. 26, 847–855 (1986).
    [CrossRef] [PubMed]
  17. W. H. Miller, G. D. Bernard, “Averaging over the foveal receptor aperture curtails aliasing,” Vision Res. 23, 1365–1370 (1983).
    [CrossRef] [PubMed]
  18. We assume a luminance of 50 cd/m2for the estimates of pupil diameter. Brown et al.4 also calculated numerical apertures and concluded that the aperture is constant across age under conditions of full dark adaptation and at a luminance of −2.6 log cd/m2. They argued, however, that the aperture is higher in infants at 0.55 log cd/m2and higher. The latter conclusion apparently stems from their own measurements of pupil diameter. This conclusion is inconsistent with that of M. S. Banks, “The development of visual accommodation during early infancy,” Child Dev. 51, 646–666 (1980), who reported that adult pupil diameters are larger than those of 4- to 12-week-old infants at 0.9 log cd/m2. It is also inconsistent with the data for 1-month-old infants and consistent with the data for 2-month-old infants reported by Salapatek and Banks.14
    [CrossRef] [PubMed]
  19. R. A. Bone, J. T. Landrum, L. Fernandez, S. L. Tarsis, “Analysis of macular pigment by HPLC: retinal distribution and age study,” Invest. Ophthalmol. Vis. Sci. 29, 843–849 (1988); J. S. Werner, “Development of scotopic sensitivity and the absorption spectrum of the human ocular media,” J. Opt. Soc. Am. 72, 247–258 (1982). We did not incorporate absorption by retinal structures anterior to the receptors even though the inner nuclear and ganglion cell layers overlay the receptor layer of the central fovea at birth (see Refs. 16 and 20).
    [CrossRef] [PubMed]
  20. I. Abramov, J. Gordon, A. Hendrickson, L. Hainline, V. Dobson, E. LaBossiere, “The retina of the newborn human infant,” Science 217, 265–267 (1982); L. Bach, R. Seefelder, Atlas zur Entwicklungsgeschichte des Menschlichen Auges (Englemann, Leipzig, Germany, 1914).
    [CrossRef] [PubMed]
  21. Here we give the details of this argument. R. A. Williams, R. G. Boothe [“Development of optical quality in the infant monkey (Macaca nemestrina) eye,” Invest. Ophthalmol. Vis. Sci. 21, 728–736 (1981)] measured OTF’s in infant and adult Macaca nemestina, a species whose visual system at maturity is in many respects similar to the human adult system. Williams and Boothe found that optical transfer is only slightly poorer at birth than in adulthood. They concluded, consequently, that the optical quality of the young macaque eye greatly exceeds the resolution performance of the system as a whole. We do not know whether the optical quality of the human neonate’s eye is similar to that of the macaque newborn’s eye, but we can estimate the possible contributions of each of several possible optical imperfections: diffraction caused by the pupil, spherical aberration, chromatic aberration, and the clarity of the optic media. Optical degradation as a result of pupillary diffraction should be similar in newborns and adults because their numerical apertures are similar. In regard to spherical and chromatic aberration, unreasonably large amounts would be needed to constrain performance at spatial frequencies of 2 cycles/deg and less. The ocular media could be a significant limit if they were particularly turgid, but ophthalmoloscopic examination reveals clear media in the normal neonate [see, e.g., R. C. Cook, R. E. Glasscock, “Refractive and ocular findings in the newborn,” Am. J. Ophthalmol. 34, 1407–1413 (1951)]. Consequently, pupillary diffraction, spherical and chromatic aberrations, and media clarity probably do not impose significant constraints on early visual performance. Early spatial vision might be constrained by another optical error: inaccurate accommodation. This hypothesis is reasonable because accommodation, like acuity, improves notably during the first months of life.18 If accommodative error were an important limitation, one would expect the acuity of neonates to vary with target distance. On the contrary, several investigators showed that grating acuity does not vary with distance [See Ref. 22; P. Salapatek, A. G. Bechtold, E. W. Bushnell, “Infant visual acuity as a function of viewing distance,” Child Dev. 47, 860–863 (1976)]. Thus inaccurate accommodation does not appear to be a significant limitation to neonatal acuity and contrast sensitivity. In sum, the quality of the retinal image almost certainly surpasses the resolution performance of the young visual system. This state of affairs is reminiscent of the retinal periphery in the mature eye.23 Unlike those in the fovea, peripheral optics are superior to the spatial grain of the receptor lattice. Consequently, adults are able to detect aliasing under conventional viewing conditions [R. A. Smith, P. F. Cass, “Aliasing in the parafovea with incoherent light,” J. Opt. Soc. Am. A 4, 1530–1534 (1987); L. N. Thibos, D. J. Walsh, F. E. Cheney, “Vision beyond the resolution limit: aliasing in the periphery,” Vision Res. 27, 2193–2197 (1987)]. This raises the intriguing possibility that young infants can detect alias in everyday viewing.
    [CrossRef] [PubMed]
  22. J. Atkinson, O. Braddick, K. Moar, “Development of contrast sensitivity over the first three months of life in the human infant,” Vision Res. 17, 1037–1044 (1977).
    [CrossRef]
  23. D. G. Green, “Regional variations in the visual acuity for interference fringes on the retina,” J. Physiol. 207, 351–356 (1970);D. R. Williams, “Aliasing in human foveal vision,” Vision Res. 25, 195–205 (1985).
    [CrossRef] [PubMed]
  24. F. W. Campbell, R. W. Gubisch, “Optical quality of the human eye,” J. Physiol. 186, 558–578 (1966).
  25. A. Hendrickson, C. Yuodelis, “The morphological development of the human fovea,” Ophthalmologica 91, 603–612 (1984).
  26. Our estimates of the diameter of the rod-free zone, the foveola, are based on the data of Ref. 16. The estimate for the adult is slightly larger than that of S. L. Polyak [The Retina (U. Chicago Press, Chicago, Ill., 1941)], who reported 1.7–2.0 deg, and much larger than that of G. Oesterberg [“Topography of the layer of rods and cones in the human retina,” Acta Ophthalmol. Suppl. 6, 1–102 (1935)], who reported 1.0 deg. We use the estimate from Ref. 16 because it was obtained with better histological techniques.
  27. A completely rigorous treatment would require consideration of physical-optical principles such as diffraction. However, the geometric-optics model is quite accurate when the ratio of stimulus wavelength divided by inner segment diameter is less than 1.0 [R. Winston, “The visual receptor as a light collector,” in Vertebrate Photoreceptor Optics, J. M. Enoch, F. L. Tobey, eds. (Springer-Verlag, Berlin, 1981)]. The ratio is less than 0.1 for both central and foveal slope cones in the neonate, so the use of geometric optics is unlikely to distort estimates of the effective collecting areas.
    [CrossRef]
  28. There are no quantitative data on the geometry of the newborn cone lattice, but newborn cones are probably roughly triangularly arranged for the following reasons. Inner segment diameters are 64–96% of the cone-to-cone separation in newborns and 74–89% of the cone-to-cone spacing in adults.16 Thus newborn cones are packed approximately as tightly as are adult cones. Tightly packed lattices tend to adopt triangular (or hexagonal) geometries [A. J. Ahumada, A. Poirson, “Modelling the irregularity of the fovealor mosaic,” Invest. Ophthalmol. Vis. Sci. Suppl. 27, 94 (1986)]. Furthermore, the foveal cone lattice of newborn macques, a species whose retinal development mirrors that of humans, appears more triangular than rectangular [O. Packer, Department of Psychology, University of Washington, Seattle, Washington 98195 (personal communication 1988)]. We assumed for these reasons that the geometry of the newborn lattice is nearly triangular. It does appear, however, that the neonatal foveal cone lattice is somewhat less regular than that of the adult [O. Packer (personal communication, 1988)], but the functional consequences of a slightly irregular lattice are undoubtedly small for most of the tasks considered in this paper. It was shown [W. S. Geisler, K. D. Davila, “Ideal discriminators in spatial vision: two point stimuli,” J. Opt. Soc. Am. A 2, 1483–1492 (1985)], for example, that ideal vernier thresholds are unaffected by moderate changes in lattice regularity. The most-noticeable effects are probably on grating acuity, particularly when performance approaches the Nyquist limit of the receptor lattice [J. I. Yellott, “Consequences of spatially irregular sampling for reconstruction of photon noisy images,” Invest. Ophthalmol. Vis. Sci. Suppl. 28, 137 (1987)].
    [CrossRef] [PubMed]
  29. O. Estevez, “On the fundamental data-base of normal and dichromatic color vision,” doctoral dissertation (University of Amsterdam, Amsterdam, The Netherlands, 1979).
  30. The same ratio was used at all ages for two reasons: (1) The few existing data suggest that all the cones are present before birth [Ref. 16; A. Hendrickson, C. Kupfer, “The histogenesis of the fovea in the macaque monkey,” Invest. Ophthalmol. 15, 746–756 (1976)], so it is unlikely that the proportion of different cone types changes postnatally. It remains possible, however, that one or more cone types are present but dysfunctional early in life, in which case the proportions of functional cones may differ from our assumption. (2) Throughout this paper we have adopted the strategy of assuming that newborn properties are adultlike unless there are data to the contrary.
  31. P. L. Walraven, “A closer look at the tritanopic convergence point,” Vision Res. 14, 1339–1343 (1974).
    [CrossRef] [PubMed]
  32. M. S. Banks, W. S. Geisler, P. J. Bennett, “The physical limits of grating visibility,” Vision Res. 27, 1915–1924 (1987).
    [CrossRef] [PubMed]
  33. J. Crowell, M. S. Banks, S. J. Anderson, W. S. Geisler, “Physical limits of grating visibility: fovea and periphery,” Invest. Ophthalmol. Vis. Sci. Suppl. 29, 139 (1988).
  34. E. R. Howell, R. F. Hess, “The functional area for summation to threshold for sinusoidal gratings,” Vision Res. 18, 369–374 (1978); J. J. Koenderink, M. A. Bouman, A. E. Bueno de Mesquita, S. Slappendel, “Perimetry of contrast detection thresholds of moving spatial sine wave patterns. III. The target extent as a sensitivity controlling parameter,” J. Opt. Soc. Am. 68, 854–860 (1978).
    [CrossRef] [PubMed]
  35. For a detailed discussion of the ideal observer that we used, see Refs. 7 and 8. The ideal observer has complete knowledge of the two stimuli to be discriminated and of the Poisson variability associated with them. From this, it constructs a tailored linear weighting function for the specific pair of stimuli. In the case of discriminating a Gabor patch from a uniform field, it constructs a weighting function (a receptive field) that is similar to but not identical to the Gabor patch itself. A stimulus is presented, and if the summed response across the weighted receptor outputs exceeds zero, the observer guesses that the Gabor patch was presented; otherwise it guesses that the uniform field was presented.
  36. With small grating patches in a contrast discrimination task,33 sensitivity of the real observers is within a factor of 4 of ideal contrast sensitivity.
  37. A. M. Norcia, Smith-Kettlewell Institute, 2232 Webster Street, San Francisco, California 94115 (personal communication, 1988).
  38. F. W. Campbell, J. G. Robson, “Application of Fourier analysis to the visibility of gratings,” J. Physiol. 197, 551–556 (1968).
  39. M. S. Banks, P. Salapatek, “Acuity and contrast sensitivity in 1-, 2-, and 3-month-old human infants,” Invest. Ophthalmol. 17, 361–365 (1978); “Infant pattern vision: a new approach based on the contrast sensitivity function,” J. Exp. Child Psychol. 31, 1–45 (1981).
    [PubMed]
  40. M. Pirchio, D. Spinelli, A. Fiorentini, L. Maffei, “Infant contrast sensitivity evaluated by evoked potentials,” Brain Res. 141, 179–184 (1978); A. M. Norcia, C. W. Tyler, D. Allen, “Electrophysiological assessment of contrast sensitivity in human infants,” Am. J. Optom. Physiol. Opt. 63, 12–15 (1986).
    [CrossRef] [PubMed]
  41. V. Dobson, D. Y. Teller, “Visual acuity in human infants: a review and comparison of behavioral and electrophysiological techniques,” Vision Res. 18, 1469–1483 (1978).
    [CrossRef]
  42. A. M. Norcia, C. W. Tyler, “Spatial frequency sweep VEP: visual acuity during the first year of life,” Vision Res. 25, 1399–1408 (1985).
    [CrossRef] [PubMed]
  43. We have examined how the parameters chosen for the neonatal ideal observer affect these results. Changes in most of the parameters cause only vertical shifting of the ideal CSF. These include pupil diameter, ocular media transmittance, and outer segment efficiency. Two other parameters cause nearly vertical shifting: receptor aperture and posterior nodal distance. Because ideal contrast sensitivity follows square-root law, an increase in any of these parameters (pupil area, media transmittance, etc.) by itself produces a square-root increase in sensitivity without affecting the shape of the CSF much, if at all. Outer segment efficiency and receptor aperture (which, along with receptor spacing, determines cone coverage) differ most between neonates and adults, so these parameters have by far the largest effects on the relative efficiency of the neonatal ideal observer. Two parameters, the OTF and the assumed spatial summation area, are the primary determinants of the shape of the ideal CSF. In both cases, we assumed adult values.21,34 Obviously, if optical transfer were significantly worse in neonatal eyes, the high-frequency roll-off of the ideal CSF would be steeper. If summation areas were constant (in degrees) across spatial frequency, the high-frequency roll-off would be shallower.
  44. Two pieces of evidence suggest, but by no means prove, that newborns fixate visual targets foveally: (1) Neonates seem to use a consistent retinal locus when fixating a high-contrast target [Ref. 3; L. Hainline, C. Harris, “Does foveal development influence the consistency of infants’ point of visual regard?” Infant Behav. Dev. 11, 129 (1988); A. M. Slater, J. M. Findlay, “Binocular fixation in the newborn baby,” J. Exp. Child Psychol. 20, 248–273 (1975)]. It was not demonstrated, however, that this locus is the fovea because of uncertainties about the location of the visual axis with respect to the optic axis. (2) Retinal and central nervous development in macaques and humans is similar, except that macaques are somewhat more advanced at birth and mature more rapidly [R. G. Boothe, R. A. Williams, L. Kiorpes, D. Y. Teller, “Development of contrast sensitivity in infant Macaca nemestrina monkeys,” Science 208, 1290–1292 (1980); P. M. Kiely, S. G. Crewther, J. Nathan, N. A. Brennan, N. Efron, M. Madigan, “A comparison of ocular development of the cynomolgus monkey and man,” Clin. Vis. Sci. 3, 269–280 (1987); Ref. 30]. C. Blakemore, F. Vital-Durand [“Development of the neural basis of visual acuity in monkeys. Speculation on the origin of deprivation amblyopia,” Trans. Ophthalmol. Soc. U.K. 99, 363–368 (1980)] measured the visual resolution of lateral geniculate nucleus cells supplied by different retinal regions. They found much higher resolution among cells supplied by the fovea than among cells supplied by the periphery in 21-week-old and adult macaques. In newborn macaques, the acuity of foveal cells was diminished but still higher than the acuity of peripheral cells. Thus, in macaque infants anyway, the highest resolution is likely to be observed with central vision. The same appears to be true for human infants. T. L. Lewis, D. Maurer, D. Kay [“Newborns’ central vision: whole or hole?” J. Exp. Child Psychol. 26, 193–203 (1978)] found that newborns could detect a narrower light bar against a dark background when it was presented in central vision than when it was presented in the periphery. These pieces of evidence suggest that newborn contrast sensitivity and acuity estimates are manifestations of central rather than peripheral processing, but more direct experimental evidence clearly is needed to settle the issue.
    [CrossRef] [PubMed]
  45. D. M. Levi, S. A. Klein, “Hyperacuity and amblyopia,” Nature 298, 268–270 (1982).
    [CrossRef] [PubMed]
  46. D. M. Levi, S. A. Klein, A. P. Aitsebaomo, “Vernier acuity, crowding, and cortical magnification,” Vision Res. 25, 963–977 (1985).
    [CrossRef]
  47. G. Westheimer, “The spatial grain of the perifoveal visual field,” Vision Res. 22, 157–162 (1982).
    [CrossRef] [PubMed]
  48. R. E. Manny, S. A. Klein, “The development of vernier acuity in infants,” Curr. Eye Res. 3, 453–462 (1984).
    [CrossRef] [PubMed]
  49. R. E. Manny, S. A. Klein, “A three-alternative tracking paradigm to measure vernier acuity of older infants,” Vision Res. 25, 1245–1252 (1985).
    [CrossRef]
  50. S. Shimojo, E. E. Birch, J. Gwiazda, R. Held, “Development of vernier acuity in infants,” Vision Res. 24, 721–728 (1984).
    [CrossRef] [PubMed]
  51. D. Allen, P. J. Bennett, M. S. Banks, “Effects of luminance on FPL and VEP acuity in human infants,” Invest. Ophthalmol. Vis. Sci. Suppl. 28, 5 (1987); V. Dobson, D. Salem, J. B. Carson, “Visual acuity in infants—the effect of variations in stimulus luminance within the photopic range,” Invest. Ophthalmol. Vis. Sci. 24, 519–522 (1983).
    [PubMed]
  52. D. R. Peeples, D. Y. Teller, “Color vision and brightness discrimination in two-month-old infants,” Science 189, 1102–1103 (1975).
    [CrossRef]
  53. D. Y. Teller, D. R. Peeples, M. Sekel, “Discrimination of chromatic from white light by two-month-old human infants,” Vision Res. 18, 41–48 (1978).
    [CrossRef] [PubMed]
  54. R. D. Hamer, K. Alexander, D. Y. Teller, “Rayleigh discriminations in young human infants,” Vision Res. 22, 575–588 (1984).
    [CrossRef]
  55. O. Packer, E. E. Hartmann, D. Y. Teller, “Infant color vision: the effect of test field size on Rayleigh discriminations,” Vision Res. 24, 1247–1260 (1984).
    [CrossRef] [PubMed]
  56. D. Varner, J. E. Cook, M. E. Schneck, M. A. McDonald, D. Y. Teller, “Tritan discrimination by 1- and 2-month-old human infants,” Vision Res. 25, 821–831 (1985).
    [CrossRef]
  57. In retrospect, the data are not really consistent with this hypothesis because the failure to discriminate yellow-greens from yellowish-white is, if anything, more consistent with a protan or deutan defect.
  58. There are two methodological shortcomings in the studies of R. J. Adams, D. Maurer, M. Davis [“Newborns’ discrimination of chromatic from achromatic stimuli,” J. Exp. Child Psychol. 41, 267–281 (1986)] and D. Maurer, R. J. Adams [“Emergence of the ability to discriminate a blue from gray at one month of age,” J. Exp. Child Psychol. 44, 147–156 (1987)]. First and most important, they did not vary the intensity of their chromatic stimuli for each infant. Instead, different intensities were presented to different groups of children. If group looking times were, at all intensities, significantly greater to the chromatic checkerboards than to the uniform fields, they concluded that infants were able to differentiate on the basis of hue alone. If dips in performance were observed at particular check intensities, they concluded that infants based their responses on brightness cues. The validity of the former conclusion hinges on the untested assumption that equiluminant points are similar for all infants of a given age. If such points vary from child to child, the absence of performance dips does not rule out the possibility that some infants based their looking preferences on brightness at each stimulus intensity. Second, even if equiluminance did not vary significantly across children, the performance criterion of Maurer and Adams was much more lenient than that of Teller. Maurer and Adams required only that looking times be statistically significantly greater with the checkerboards than with the uniform field. Teller and colleagues52–56 required at least 70% correct performance from each infant at all stimulus intensities.
    [CrossRef] [PubMed]
  59. K. T. Mullen, “The contrast sensitivity of human color vision to red/green and blue/yellow chromatic gratings,” J. Physiol. 359, 381–400 (1985).
  60. E. M. Granger, J. C. Heurtley, “Visual chromaticity modulation transfer function,” J. Opt. Soc. Am. 63, 1173–1174 (1973); D. H. Kelly, “Spatiotemporal variation of chromatic and achromatic contrast thresholds,” J. Opt. Soc. Am. 73, 742–750 (1983); G. J. C. van der Horst, C. M. M. de Weert, M. A. Bouman, “Transfer of spatial chromaticity-contrast at threshold in the human eye,” J. Opt. Soc. Am. 57, 1260–1266 (1967).
    [CrossRef] [PubMed]
  61. C. F. Stromeyer, G. R. Cole, R. E. Kronauer, “Second-site adaptation in the red-green chromatic pathways,” Vision Res. 25, 219–238 (1985).
    [CrossRef] [PubMed]
  62. The ideal observer of Table 1 follows square-root law in chromatic contrast sensitivity tasks.G. J. C. van der Horst, M. A. Bouman [“Spatio-temporal chromaticity discrimination,” J. Opt. Soc. Am. 59, 1482–1488 (1969)] measured contrast sensitivity with isoluminant gratings for a wide range of photopic illuminances. They found that chromatic contrast sensitivity (defined in a fashion similar to that in Ref. 59) increased as the square-root of illuminance from 1.2 to 160 photopic trolands, the highest light level presented. Square-root law only held for frequencies greater than 3 cycles/deg; at lower frequencies, Weber’s law was observed at the higher illuminances. Thus, as with luminance contrast sensitivity,32,33 the luminance dependence of ideal chromatic contrast sensitivity is similar to that of real observers, at least for intermediate to high spatial frequencies.
    [CrossRef] [PubMed]
  63. A. M. Derrington, J. Krauskopf, P. Lennie, “Chromatic mechanisms in lateral geniculate nucleus of macaque,” J. Physiol. 357, 241–265 (1984);R. L. De Valois, I. Abramov, G. H. Jacobs, “Analysis of response patterns of LGN cells,” J. Opt. Soc. Am. 56, 966–977 (1966).
    [CrossRef] [PubMed]
  64. To understand this, it is useful to consider an isoluminant red–green grating separated into its two components: a red–black grating and a green–black grating. When the red component is presented, LWS cones respond in rough proportion to the luminance variation from the peak to the trough of the grating. They also respond in this way, though at somewhat reduced levels, to the green component. When the red and green grating components are added in phase, producing a yellow–black grating, the LWS cone modulations that are due to each component add, producing a large overall modulation. When the components are added in opposite phase, producing an isoluminant red–green grating, the LWS cone modulations to each component cancel to some degree, and the overall modulation is smaller. The same reasoning obviously applies to the MWS cones.
  65. There is indirect evidence that all three cone types are functional at birth. D. R. Peeples, D. Y. Teller [“White-adapted photopic spectral sensitivity in human infants,” Vision Res. 18, 49–53 (1978)] and A. Moskowitz-Cook [“The development of photopic spectral sensitivity in human infants,” Vision Res. 18, 1133–1142 (1979)] showed that the photopic spectral sensitivity of infants is similar to that of adults. Their observations suggest that MWS and LWS cones are functional early in life. The small differences between neonatal and adult photopic spectral sensitivities probably are explained by age-related changes in the ocular media.19V. J. Volbrecht, J. S. Werner [“Isolation of short-wavelength-sensitive cone photoreceptors in 4–6-week-old human infants,” Vision Res. 27, 469–478 (1987)] used a chromatic adaptation paradigm to demonstrate the presence of SWS cones in young infants. Although the results of these three studies imply the existence of three functional cone types, they do not indicate whether the infant visual system can preserve and compare signals from one cone type to another. Moreover, the data of Volbrecht and Werner do not inform us about the relative sensitivity of SWS cones early in life.
    [CrossRef] [PubMed]
  66. Because neonatal outer segments are shorter than adult segments, they probably exhibit less self-screening.67 In consequence, neonatal action spectra should be narrower than adult spectra. We have not incorporated this effect into the newborn ideal observer because it is likely to be quite small for the tasks that we consider. It should be noted, however, that the narrowing of action spectra should cause the color-matching and luminosity functions of neonates to differ from those of adults. For instance, one would predict that the green–red setting in an anomaloscopelike experiment would be lower in infants’ central vision just as it is in adults’ peripheral vision [J. Pokorny, V. C. Smith, “Effect of field size on red–green color mixture equations,” J. Opt. Soc. Am. 66, 705–708 (1976)]. In addition, one would predict the relative luminous efficiency of long-wavelength lights to be lower in neonates’ central vision. Interestingly, Hamer et al.,54 Packer et al.,55 and J. E. Clavadetscher [“Young infants show a relative insensitivity to long wavelength (red) light,” Infant Behav. Dev. Suppl.11, (1988)] reported such an effect in young infants.
    [CrossRef] [PubMed]
  67. G. Wyszecki, W. S. Stiles, Color Science: Concepts and Methods, Quantitative Data, and Formulae (Wiley, New York, 1982).
  68. For details on the ideal observer’s decision strategy in such tasks, consult Ref. 8. When asked to discriminate a 550-nm target in a 589-nm background from a uniform 589-nm background, the ideal observer constructs a weighting function consisting of positive weights for MWS cone stimulation in the target region and negative weights for LWS cone stimulation in the same region. When the summed response exceeds zero, the ideal observer guesses that the 550-nm target was presented.
  69. Increment and decrement thresholds of real infants are nearly identical when expressed in log units.53
  70. Some of the parameters of the neonatal ideal observer affect the predictions of the visual efficiency hypothesis and some do not. Pupil diameter, posterior nodal distance, receptor aperture, receptor spacing, the optical transfer function, and spatial summation area do not affect predictions at all because luminance and chromatic thresholds are affected similarly by changes in these parameters. Three parameters do influence predictions: (1) Ocular media transmittance: we assumed a higher transmittance for neonates.19 The media are nearly transparent at long wavelengths, so predictions for the Rayleigh54,55 and neutral-point52,53 experiments are virtually unaffected by the range of transmittances that we used. Predictions for the tritan experiment,56 however, are in fact affected by the media: the lighter the media, the lower the chromatic threshold of the neonatal ideal observer. (2) Relative numbers of the three cone types: within reasonable variations of the relative proportions of cone types, predictions do not vary significantly. (3) Outer segment length: self-screening affects the bandwidth of receptor absorption spectra.67 In long outer segments, self-screening is more pronounced and absorption spectra broaden. Thus neonatal foveal cones may well have narrower spectra than we assumed. The consequence of narrower spectra is an improvement in many chromatic discriminations relative to luminance discriminations. The effect is not large, however, for the chromatic tasks that we examined, so we do not incorporate it here.
  71. I. G. Priest, F. G. Brickwedde, “The perceptible colorimetric purity as a function of dominant wavelength,” J. Opt. Soc. Am. 28, 133–139 (1938); W. D. Wright, Researches on Normal and Defective Colour Vision (Klimpton, London, 1946).
    [CrossRef]
  72. V. C. Smith, R. W. Bowen, J. Pokorny, “Threshold temporal integration of chromatic stimuli,” Vision Res. 24, 653–660 (1984).
    [CrossRef] [PubMed]
  73. H. R. Wilson, D. J. Gelb, “Modified line element theory for spatial frequency and width discrimination,” J. Opt. Soc. Am. A 1, 124–131 (1984).
    [CrossRef] [PubMed]
  74. D. I. A. MacLeod, “Visual sensitivity,” Annu. Rev. Psychol. 29, 613–645 (1978).
    [CrossRef] [PubMed]
  75. D. C. Hood, “Sensitivity to light,” in Handbook of Perception and Human Performance, K. R. Boff, L. Kaufman, J. P. Thomas, eds. (Wiley, New York, 1986), pp. 5-1–5-66. The equation that we used to calculate half-bleaching constants is(1−p)/T0=I[1−exp(−Dp)]/(DQe), where p is the proportion of unbleached pigment, T0is the regeneration time constant, I is the steady retinal illuminance in trolands, D is the optical density, and Qe is the photosensitivity of the receptor in troland-seconds. The half-bleaching constants reported in the text should be modified slightly to reflect the differences in effective apertures of newborn and adult cones. If we make the assumption that 80% of the quanta incident upon the adult inner segment are transmitted to the outer segment, the adult half-bleaching illuminance is reduced by 0.3 log unit relative to the newborn value.
  76. M. S. Banks, J. L. Dannemiller, “Infant visual psychophysics,” in Handbook of Infant Perception, P. Salapatek, L. B. Cohen, eds. (Academic, New York, 1987), pp. 115–184.
  77. R. D. Hamer, M. E. Schneck, “Spatial summation in dark-adapted human infants,” Vision Res. 24, 77–85 (1984); A. B. Fulton, R. M. Hansen, C. W. Tyler, “Temporal summation in human infants,” Invest. Ophthalmol. Vis. Sci. Suppl. 29, 60 (1988).
    [CrossRef] [PubMed]
  78. J. Atkinson, O. J. Braddick, “Development of optokinetic nystagmus in infants: an indicator of cortical binocularity?” in Eye Movements: Cognition and Visual Perception, D. F. Fisher, R. A. Monty, J. W. Senders, eds. (Erlbaum, Hillsdale, N.J., 1981), pp. 53–64; M. S. Banks, B. R. Stephens, E. E. Hartmann, “The development of basic mechanisms of pattern vision: spatial frequency channels,” J. Exp. Child Psychol. 40, 501–527 (1985); O. Braddick, J. Atkinson, “Sensory selectivity, attentional control, and cross-channel integration in early visual development,” in Perceptual Development in Infancy: The Minnesota Symposium on Child Psychology, A. Yonas, ed. (Erlbaum, Hillsdale, N.J., 1987), pp. 105–143; O. Braddick, J. Wattam-Bell, J. Atkinson, “Orientation-specific cortical responses develop in early infancy,” Nature 320, 617–619 (1986).
    [CrossRef] [PubMed]
  79. A. B. Bonds, “Development of orientation tuning in the visual cortex of kittens,” in Developmental Neurobiology of Vision, R. D. Freeman, ed. (Plenum, New York, 1979); A. M. Derrington, A. F. Fuchs, “The development of spatial-frequency selectivity in kitten striate cortex,” J. Physiol. 316, 1–10 (1981);D. H. Hubel, T. N. Wiesel, “Receptive fields of cells in striate cortex of very young, visually inexperienced kittens,” J. Neurophysiol. 26, 994–1002 (1963).
    [CrossRef] [PubMed]
  80. D. I. Hamasaki, J. T. Flynn, “Physiological properties of retinal ganglion cells of 3-week-old kittens,” Vision Res. 17, 275–284 (1977).
    [CrossRef] [PubMed]
  81. This idea was suggested by W. S. Geisler, Department of Psychology, University of Texas, Austin, Texas 78712 (personal communication, 1988).
  82. C. Blakemore, F. W. Campbell, “On the existence of neurons in the human visual system selectively sensitive to the orientation and size of retinal images,” J. Physiol. 203, 237–260 (1969);F. W. Campbell, J. J. Kulikowski, “Orientational selectivity of the human visual system,” J. Physiol. 187, 437–445 (1966).
  83. J. L. Dannemiller, M. S. Banks, “The development of light adaptation in human infants,” Vision Res. 23, 599–609 (1983); R. M. Hansen, A. B. Fulton, “Behavioral measurement of background adaptation in infants,” Invest. Ophthalmol. Vis. Sci. 21, 625–629 (1981).
    [CrossRef] [PubMed]
  84. D. H. Kelly, “Visual contrast sensitivity,” Opt. Acta 24, 107–129 (1977).
    [CrossRef]
  85. J. A. Movshon, L. Kiorpes, “Analysis of the development of spatial contrast sensitivity in monkey and human infants,” J. Opt. Soc. Am. A 5, 2166–2172 (1988).
    [CrossRef] [PubMed]
  86. A. Watson, “The ideal observer concept as a modeling tool,” in Frontiers of Visual Science: Proceedings of the 1985 Symposium (National Academy of Sciences, Washington, D.C., 1987), pp. 32–37.

1988 (6)

D. S. Jacobs, C. Blakemore, “Factors limiting the postnatal development of visual acuity in the monkey,” Vision Res. 28, 947–958 (1988).
[CrossRef] [PubMed]

H. R. Wilson, “Development of spatiotemporal mechanisms in infant vision,” Vision Res. 28, 611–628 (1988).
[CrossRef] [PubMed]

R. A. Bone, J. T. Landrum, L. Fernandez, S. L. Tarsis, “Analysis of macular pigment by HPLC: retinal distribution and age study,” Invest. Ophthalmol. Vis. Sci. 29, 843–849 (1988); J. S. Werner, “Development of scotopic sensitivity and the absorption spectrum of the human ocular media,” J. Opt. Soc. Am. 72, 247–258 (1982). We did not incorporate absorption by retinal structures anterior to the receptors even though the inner nuclear and ganglion cell layers overlay the receptor layer of the central fovea at birth (see Refs. 16 and 20).
[CrossRef] [PubMed]

J. Crowell, M. S. Banks, S. J. Anderson, W. S. Geisler, “Physical limits of grating visibility: fovea and periphery,” Invest. Ophthalmol. Vis. Sci. Suppl. 29, 139 (1988).

Two pieces of evidence suggest, but by no means prove, that newborns fixate visual targets foveally: (1) Neonates seem to use a consistent retinal locus when fixating a high-contrast target [Ref. 3; L. Hainline, C. Harris, “Does foveal development influence the consistency of infants’ point of visual regard?” Infant Behav. Dev. 11, 129 (1988); A. M. Slater, J. M. Findlay, “Binocular fixation in the newborn baby,” J. Exp. Child Psychol. 20, 248–273 (1975)]. It was not demonstrated, however, that this locus is the fovea because of uncertainties about the location of the visual axis with respect to the optic axis. (2) Retinal and central nervous development in macaques and humans is similar, except that macaques are somewhat more advanced at birth and mature more rapidly [R. G. Boothe, R. A. Williams, L. Kiorpes, D. Y. Teller, “Development of contrast sensitivity in infant Macaca nemestrina monkeys,” Science 208, 1290–1292 (1980); P. M. Kiely, S. G. Crewther, J. Nathan, N. A. Brennan, N. Efron, M. Madigan, “A comparison of ocular development of the cynomolgus monkey and man,” Clin. Vis. Sci. 3, 269–280 (1987); Ref. 30]. C. Blakemore, F. Vital-Durand [“Development of the neural basis of visual acuity in monkeys. Speculation on the origin of deprivation amblyopia,” Trans. Ophthalmol. Soc. U.K. 99, 363–368 (1980)] measured the visual resolution of lateral geniculate nucleus cells supplied by different retinal regions. They found much higher resolution among cells supplied by the fovea than among cells supplied by the periphery in 21-week-old and adult macaques. In newborn macaques, the acuity of foveal cells was diminished but still higher than the acuity of peripheral cells. Thus, in macaque infants anyway, the highest resolution is likely to be observed with central vision. The same appears to be true for human infants. T. L. Lewis, D. Maurer, D. Kay [“Newborns’ central vision: whole or hole?” J. Exp. Child Psychol. 26, 193–203 (1978)] found that newborns could detect a narrower light bar against a dark background when it was presented in central vision than when it was presented in the periphery. These pieces of evidence suggest that newborn contrast sensitivity and acuity estimates are manifestations of central rather than peripheral processing, but more direct experimental evidence clearly is needed to settle the issue.
[CrossRef] [PubMed]

J. A. Movshon, L. Kiorpes, “Analysis of the development of spatial contrast sensitivity in monkey and human infants,” J. Opt. Soc. Am. A 5, 2166–2172 (1988).
[CrossRef] [PubMed]

1987 (4)

M. S. Banks, W. S. Geisler, P. J. Bennett, “The physical limits of grating visibility,” Vision Res. 27, 1915–1924 (1987).
[CrossRef] [PubMed]

D. Allen, P. J. Bennett, M. S. Banks, “Effects of luminance on FPL and VEP acuity in human infants,” Invest. Ophthalmol. Vis. Sci. Suppl. 28, 5 (1987); V. Dobson, D. Salem, J. B. Carson, “Visual acuity in infants—the effect of variations in stimulus luminance within the photopic range,” Invest. Ophthalmol. Vis. Sci. 24, 519–522 (1983).
[PubMed]

A. M. Brown, V. Dobson, J. Maier, “Visual acuity of human infants at scotopic, mesopic, and photopic luminances,” Vision Res. 27, 1845–1858 (1987).
[CrossRef]

S. Shimojo, R. Held, “Vernier acuity is less than grating acuity in 2- and 3-month-olds,” Vision Res. 27, 77–86 (1987).
[CrossRef] [PubMed]

1986 (3)

C. Yuodelis, A. Hendrickson, “A qualitative and quantitative analysis of the human fovea during development,” Vision Res. 26, 847–855 (1986).
[CrossRef] [PubMed]

There are no quantitative data on the geometry of the newborn cone lattice, but newborn cones are probably roughly triangularly arranged for the following reasons. Inner segment diameters are 64–96% of the cone-to-cone separation in newborns and 74–89% of the cone-to-cone spacing in adults.16 Thus newborn cones are packed approximately as tightly as are adult cones. Tightly packed lattices tend to adopt triangular (or hexagonal) geometries [A. J. Ahumada, A. Poirson, “Modelling the irregularity of the fovealor mosaic,” Invest. Ophthalmol. Vis. Sci. Suppl. 27, 94 (1986)]. Furthermore, the foveal cone lattice of newborn macques, a species whose retinal development mirrors that of humans, appears more triangular than rectangular [O. Packer, Department of Psychology, University of Washington, Seattle, Washington 98195 (personal communication 1988)]. We assumed for these reasons that the geometry of the newborn lattice is nearly triangular. It does appear, however, that the neonatal foveal cone lattice is somewhat less regular than that of the adult [O. Packer (personal communication, 1988)], but the functional consequences of a slightly irregular lattice are undoubtedly small for most of the tasks considered in this paper. It was shown [W. S. Geisler, K. D. Davila, “Ideal discriminators in spatial vision: two point stimuli,” J. Opt. Soc. Am. A 2, 1483–1492 (1985)], for example, that ideal vernier thresholds are unaffected by moderate changes in lattice regularity. The most-noticeable effects are probably on grating acuity, particularly when performance approaches the Nyquist limit of the receptor lattice [J. I. Yellott, “Consequences of spatially irregular sampling for reconstruction of photon noisy images,” Invest. Ophthalmol. Vis. Sci. Suppl. 28, 137 (1987)].
[CrossRef] [PubMed]

There are two methodological shortcomings in the studies of R. J. Adams, D. Maurer, M. Davis [“Newborns’ discrimination of chromatic from achromatic stimuli,” J. Exp. Child Psychol. 41, 267–281 (1986)] and D. Maurer, R. J. Adams [“Emergence of the ability to discriminate a blue from gray at one month of age,” J. Exp. Child Psychol. 44, 147–156 (1987)]. First and most important, they did not vary the intensity of their chromatic stimuli for each infant. Instead, different intensities were presented to different groups of children. If group looking times were, at all intensities, significantly greater to the chromatic checkerboards than to the uniform fields, they concluded that infants were able to differentiate on the basis of hue alone. If dips in performance were observed at particular check intensities, they concluded that infants based their responses on brightness cues. The validity of the former conclusion hinges on the untested assumption that equiluminant points are similar for all infants of a given age. If such points vary from child to child, the absence of performance dips does not rule out the possibility that some infants based their looking preferences on brightness at each stimulus intensity. Second, even if equiluminance did not vary significantly across children, the performance criterion of Maurer and Adams was much more lenient than that of Teller. Maurer and Adams required only that looking times be statistically significantly greater with the checkerboards than with the uniform field. Teller and colleagues52–56 required at least 70% correct performance from each infant at all stimulus intensities.
[CrossRef] [PubMed]

1985 (7)

K. T. Mullen, “The contrast sensitivity of human color vision to red/green and blue/yellow chromatic gratings,” J. Physiol. 359, 381–400 (1985).

C. F. Stromeyer, G. R. Cole, R. E. Kronauer, “Second-site adaptation in the red-green chromatic pathways,” Vision Res. 25, 219–238 (1985).
[CrossRef] [PubMed]

D. Varner, J. E. Cook, M. E. Schneck, M. A. McDonald, D. Y. Teller, “Tritan discrimination by 1- and 2-month-old human infants,” Vision Res. 25, 821–831 (1985).
[CrossRef]

D. G. Pelli, “Uncertainty explains many aspects of human contrast detection and discrimination,” J. Opt. Soc. Am. A 2, 1508–1532 (1985); A. B. Watson, H. B. Barlow, J. G. Robson, “What does the eye see best?” Nature 31, 419–422 (1983).
[CrossRef] [PubMed]

R. E. Manny, S. A. Klein, “A three-alternative tracking paradigm to measure vernier acuity of older infants,” Vision Res. 25, 1245–1252 (1985).
[CrossRef]

D. M. Levi, S. A. Klein, A. P. Aitsebaomo, “Vernier acuity, crowding, and cortical magnification,” Vision Res. 25, 963–977 (1985).
[CrossRef]

A. M. Norcia, C. W. Tyler, “Spatial frequency sweep VEP: visual acuity during the first year of life,” Vision Res. 25, 1399–1408 (1985).
[CrossRef] [PubMed]

1984 (10)

R. E. Manny, S. A. Klein, “The development of vernier acuity in infants,” Curr. Eye Res. 3, 453–462 (1984).
[CrossRef] [PubMed]

S. Shimojo, E. E. Birch, J. Gwiazda, R. Held, “Development of vernier acuity in infants,” Vision Res. 24, 721–728 (1984).
[CrossRef] [PubMed]

A. Hendrickson, C. Yuodelis, “The morphological development of the human fovea,” Ophthalmologica 91, 603–612 (1984).

W. S. Geisler, “Physical limits of acuity and hyperacuity,” J. Opt. Soc. Am. A 1, 775–782 (1984).
[CrossRef] [PubMed]

R. D. Hamer, K. Alexander, D. Y. Teller, “Rayleigh discriminations in young human infants,” Vision Res. 22, 575–588 (1984).
[CrossRef]

O. Packer, E. E. Hartmann, D. Y. Teller, “Infant color vision: the effect of test field size on Rayleigh discriminations,” Vision Res. 24, 1247–1260 (1984).
[CrossRef] [PubMed]

A. M. Derrington, J. Krauskopf, P. Lennie, “Chromatic mechanisms in lateral geniculate nucleus of macaque,” J. Physiol. 357, 241–265 (1984);R. L. De Valois, I. Abramov, G. H. Jacobs, “Analysis of response patterns of LGN cells,” J. Opt. Soc. Am. 56, 966–977 (1966).
[CrossRef] [PubMed]

V. C. Smith, R. W. Bowen, J. Pokorny, “Threshold temporal integration of chromatic stimuli,” Vision Res. 24, 653–660 (1984).
[CrossRef] [PubMed]

H. R. Wilson, D. J. Gelb, “Modified line element theory for spatial frequency and width discrimination,” J. Opt. Soc. Am. A 1, 124–131 (1984).
[CrossRef] [PubMed]

R. D. Hamer, M. E. Schneck, “Spatial summation in dark-adapted human infants,” Vision Res. 24, 77–85 (1984); A. B. Fulton, R. M. Hansen, C. W. Tyler, “Temporal summation in human infants,” Invest. Ophthalmol. Vis. Sci. Suppl. 29, 60 (1988).
[CrossRef] [PubMed]

1983 (2)

J. L. Dannemiller, M. S. Banks, “The development of light adaptation in human infants,” Vision Res. 23, 599–609 (1983); R. M. Hansen, A. B. Fulton, “Behavioral measurement of background adaptation in infants,” Invest. Ophthalmol. Vis. Sci. 21, 625–629 (1981).
[CrossRef] [PubMed]

W. H. Miller, G. D. Bernard, “Averaging over the foveal receptor aperture curtails aliasing,” Vision Res. 23, 1365–1370 (1983).
[CrossRef] [PubMed]

1982 (3)

I. Abramov, J. Gordon, A. Hendrickson, L. Hainline, V. Dobson, E. LaBossiere, “The retina of the newborn human infant,” Science 217, 265–267 (1982); L. Bach, R. Seefelder, Atlas zur Entwicklungsgeschichte des Menschlichen Auges (Englemann, Leipzig, Germany, 1914).
[CrossRef] [PubMed]

D. M. Levi, S. A. Klein, “Hyperacuity and amblyopia,” Nature 298, 268–270 (1982).
[CrossRef] [PubMed]

G. Westheimer, “The spatial grain of the perifoveal visual field,” Vision Res. 22, 157–162 (1982).
[CrossRef] [PubMed]

1981 (1)

Here we give the details of this argument. R. A. Williams, R. G. Boothe [“Development of optical quality in the infant monkey (Macaca nemestrina) eye,” Invest. Ophthalmol. Vis. Sci. 21, 728–736 (1981)] measured OTF’s in infant and adult Macaca nemestina, a species whose visual system at maturity is in many respects similar to the human adult system. Williams and Boothe found that optical transfer is only slightly poorer at birth than in adulthood. They concluded, consequently, that the optical quality of the young macaque eye greatly exceeds the resolution performance of the system as a whole. We do not know whether the optical quality of the human neonate’s eye is similar to that of the macaque newborn’s eye, but we can estimate the possible contributions of each of several possible optical imperfections: diffraction caused by the pupil, spherical aberration, chromatic aberration, and the clarity of the optic media. Optical degradation as a result of pupillary diffraction should be similar in newborns and adults because their numerical apertures are similar. In regard to spherical and chromatic aberration, unreasonably large amounts would be needed to constrain performance at spatial frequencies of 2 cycles/deg and less. The ocular media could be a significant limit if they were particularly turgid, but ophthalmoloscopic examination reveals clear media in the normal neonate [see, e.g., R. C. Cook, R. E. Glasscock, “Refractive and ocular findings in the newborn,” Am. J. Ophthalmol. 34, 1407–1413 (1951)]. Consequently, pupillary diffraction, spherical and chromatic aberrations, and media clarity probably do not impose significant constraints on early visual performance. Early spatial vision might be constrained by another optical error: inaccurate accommodation. This hypothesis is reasonable because accommodation, like acuity, improves notably during the first months of life.18 If accommodative error were an important limitation, one would expect the acuity of neonates to vary with target distance. On the contrary, several investigators showed that grating acuity does not vary with distance [See Ref. 22; P. Salapatek, A. G. Bechtold, E. W. Bushnell, “Infant visual acuity as a function of viewing distance,” Child Dev. 47, 860–863 (1976)]. Thus inaccurate accommodation does not appear to be a significant limitation to neonatal acuity and contrast sensitivity. In sum, the quality of the retinal image almost certainly surpasses the resolution performance of the young visual system. This state of affairs is reminiscent of the retinal periphery in the mature eye.23 Unlike those in the fovea, peripheral optics are superior to the spatial grain of the receptor lattice. Consequently, adults are able to detect aliasing under conventional viewing conditions [R. A. Smith, P. F. Cass, “Aliasing in the parafovea with incoherent light,” J. Opt. Soc. Am. A 4, 1530–1534 (1987); L. N. Thibos, D. J. Walsh, F. E. Cheney, “Vision beyond the resolution limit: aliasing in the periphery,” Vision Res. 27, 2193–2197 (1987)]. This raises the intriguing possibility that young infants can detect alias in everyday viewing.
[CrossRef] [PubMed]

1980 (1)

We assume a luminance of 50 cd/m2for the estimates of pupil diameter. Brown et al.4 also calculated numerical apertures and concluded that the aperture is constant across age under conditions of full dark adaptation and at a luminance of −2.6 log cd/m2. They argued, however, that the aperture is higher in infants at 0.55 log cd/m2and higher. The latter conclusion apparently stems from their own measurements of pupil diameter. This conclusion is inconsistent with that of M. S. Banks, “The development of visual accommodation during early infancy,” Child Dev. 51, 646–666 (1980), who reported that adult pupil diameters are larger than those of 4- to 12-week-old infants at 0.9 log cd/m2. It is also inconsistent with the data for 1-month-old infants and consistent with the data for 2-month-old infants reported by Salapatek and Banks.14
[CrossRef] [PubMed]

1979 (1)

Most of the growth of the eye occurs in the first year. Axial length, for instance, is 16–17 mm at birth, 20–21 mm at 1 year, and 23–25 mm in adolescence and adulthood [see Ref. 13; S. Hirano, Y. Yamamoto, H. Takayama, Y. Sugata, K. Matsuo, “Ultrasonic observations of eyes in premature babies. Part 6: growth curves of ocular axial length and its components,” Acta Soc. Ophthalmol. Jpn. 83, 1679–1693 (1979)]. Image magnification is proportional to posterior nodal distance [A. G. Bennett, J. L. Francis, “Aberrations of optical images,” in The Eye, H. Davson, ed. (Academic, New York, 1962)], and so calculations of age-related changes in magnification require estimates of the nodal distance at different ages. The only schematic eyes described for the newborn [J. M. Enoch, R. D. Hamer, “Image size correction of the unilateral aphakic infant,” Ophthalmol. Pediatr. Genet. 2, 153–165 (1983); W. Lotmar, “A theoretical model for the eye of new-born infants,” Albrecht von Graefes Archiv. Klin. Exp. Ophthalmol. 198, 179–185 (1976)] have posterior nodal distances of 10.3–12.0 mm, roughly 2/3 of the adult distance. For a given target in space, then, retinal image size in the eye of the newborn infant should be 2/3 of that in the mature eye. Stated another way, a 1-deg target should subtend 204 μ m on the retina of a newborn infant and 298 μ m on the retina of an adult.
[CrossRef]

1978 (7)

M. S. Banks, P. Salapatek, “Acuity and contrast sensitivity in 1-, 2-, and 3-month-old human infants,” Invest. Ophthalmol. 17, 361–365 (1978); “Infant pattern vision: a new approach based on the contrast sensitivity function,” J. Exp. Child Psychol. 31, 1–45 (1981).
[PubMed]

M. Pirchio, D. Spinelli, A. Fiorentini, L. Maffei, “Infant contrast sensitivity evaluated by evoked potentials,” Brain Res. 141, 179–184 (1978); A. M. Norcia, C. W. Tyler, D. Allen, “Electrophysiological assessment of contrast sensitivity in human infants,” Am. J. Optom. Physiol. Opt. 63, 12–15 (1986).
[CrossRef] [PubMed]

V. Dobson, D. Y. Teller, “Visual acuity in human infants: a review and comparison of behavioral and electrophysiological techniques,” Vision Res. 18, 1469–1483 (1978).
[CrossRef]

E. R. Howell, R. F. Hess, “The functional area for summation to threshold for sinusoidal gratings,” Vision Res. 18, 369–374 (1978); J. J. Koenderink, M. A. Bouman, A. E. Bueno de Mesquita, S. Slappendel, “Perimetry of contrast detection thresholds of moving spatial sine wave patterns. III. The target extent as a sensitivity controlling parameter,” J. Opt. Soc. Am. 68, 854–860 (1978).
[CrossRef] [PubMed]

D. I. A. MacLeod, “Visual sensitivity,” Annu. Rev. Psychol. 29, 613–645 (1978).
[CrossRef] [PubMed]

There is indirect evidence that all three cone types are functional at birth. D. R. Peeples, D. Y. Teller [“White-adapted photopic spectral sensitivity in human infants,” Vision Res. 18, 49–53 (1978)] and A. Moskowitz-Cook [“The development of photopic spectral sensitivity in human infants,” Vision Res. 18, 1133–1142 (1979)] showed that the photopic spectral sensitivity of infants is similar to that of adults. Their observations suggest that MWS and LWS cones are functional early in life. The small differences between neonatal and adult photopic spectral sensitivities probably are explained by age-related changes in the ocular media.19V. J. Volbrecht, J. S. Werner [“Isolation of short-wavelength-sensitive cone photoreceptors in 4–6-week-old human infants,” Vision Res. 27, 469–478 (1987)] used a chromatic adaptation paradigm to demonstrate the presence of SWS cones in young infants. Although the results of these three studies imply the existence of three functional cone types, they do not indicate whether the infant visual system can preserve and compare signals from one cone type to another. Moreover, the data of Volbrecht and Werner do not inform us about the relative sensitivity of SWS cones early in life.
[CrossRef] [PubMed]

D. Y. Teller, D. R. Peeples, M. Sekel, “Discrimination of chromatic from white light by two-month-old human infants,” Vision Res. 18, 41–48 (1978).
[CrossRef] [PubMed]

1977 (3)

D. I. Hamasaki, J. T. Flynn, “Physiological properties of retinal ganglion cells of 3-week-old kittens,” Vision Res. 17, 275–284 (1977).
[CrossRef] [PubMed]

D. H. Kelly, “Visual contrast sensitivity,” Opt. Acta 24, 107–129 (1977).
[CrossRef]

J. Atkinson, O. Braddick, K. Moar, “Development of contrast sensitivity over the first three months of life in the human infant,” Vision Res. 17, 1037–1044 (1977).
[CrossRef]

1976 (2)

The same ratio was used at all ages for two reasons: (1) The few existing data suggest that all the cones are present before birth [Ref. 16; A. Hendrickson, C. Kupfer, “The histogenesis of the fovea in the macaque monkey,” Invest. Ophthalmol. 15, 746–756 (1976)], so it is unlikely that the proportion of different cone types changes postnatally. It remains possible, however, that one or more cone types are present but dysfunctional early in life, in which case the proportions of functional cones may differ from our assumption. (2) Throughout this paper we have adopted the strategy of assuming that newborn properties are adultlike unless there are data to the contrary.

Because neonatal outer segments are shorter than adult segments, they probably exhibit less self-screening.67 In consequence, neonatal action spectra should be narrower than adult spectra. We have not incorporated this effect into the newborn ideal observer because it is likely to be quite small for the tasks that we consider. It should be noted, however, that the narrowing of action spectra should cause the color-matching and luminosity functions of neonates to differ from those of adults. For instance, one would predict that the green–red setting in an anomaloscopelike experiment would be lower in infants’ central vision just as it is in adults’ peripheral vision [J. Pokorny, V. C. Smith, “Effect of field size on red–green color mixture equations,” J. Opt. Soc. Am. 66, 705–708 (1976)]. In addition, one would predict the relative luminous efficiency of long-wavelength lights to be lower in neonates’ central vision. Interestingly, Hamer et al.,54 Packer et al.,55 and J. E. Clavadetscher [“Young infants show a relative insensitivity to long wavelength (red) light,” Infant Behav. Dev. Suppl.11, (1988)] reported such an effect in young infants.
[CrossRef] [PubMed]

1975 (1)

D. R. Peeples, D. Y. Teller, “Color vision and brightness discrimination in two-month-old infants,” Science 189, 1102–1103 (1975).
[CrossRef]

1974 (2)

P. L. Walraven, “A closer look at the tritanopic convergence point,” Vision Res. 14, 1339–1343 (1974).
[CrossRef] [PubMed]

G. Bronson, “The postnatal growth of visual capacity,” Child Dev. 45, 873–890 (1974); P. Salapatek, “Pattern perception in early infancy,” in Infant Perception: From Sensation to Cognition, L. B. Cohen, P. Salapatek, eds. (Academic, New York, 1975), pp. 133–248.
[CrossRef] [PubMed]

1973 (1)

1971 (1)

J. S. Larsen, “The sagittal growth of the eye. IV. Ultrasonic measurement of the axial length of the eye from birth to puberty,” Acta Ophthalmol. 49, 873–886 (1971).
[CrossRef]

1970 (1)

D. G. Green, “Regional variations in the visual acuity for interference fringes on the retina,” J. Physiol. 207, 351–356 (1970);D. R. Williams, “Aliasing in human foveal vision,” Vision Res. 25, 195–205 (1985).
[CrossRef] [PubMed]

1969 (2)

1968 (1)

F. W. Campbell, J. G. Robson, “Application of Fourier analysis to the visibility of gratings,” J. Physiol. 197, 551–556 (1968).

1966 (1)

F. W. Campbell, R. W. Gubisch, “Optical quality of the human eye,” J. Physiol. 186, 558–578 (1966).

1958 (1)

H. B. Barlow, “Temporal and spatial summation in human vision at different background intensities,” J. Physiol. 141, 337–350 (1958).

1946 (1)

S. Stenstrom, “Investigation of the variation and the correlation of the optical elements of human eyes,” Am. J. Optom. 25, 5 (1946).

1942 (1)

A. Rose, “The relative sensitivities of television pick-up tubes, photographic film, and the human eye,” Proc. IRE 30, 293–300 (1942).
[CrossRef]

1938 (1)

Abramov, I.

I. Abramov, J. Gordon, A. Hendrickson, L. Hainline, V. Dobson, E. LaBossiere, “The retina of the newborn human infant,” Science 217, 265–267 (1982); L. Bach, R. Seefelder, Atlas zur Entwicklungsgeschichte des Menschlichen Auges (Englemann, Leipzig, Germany, 1914).
[CrossRef] [PubMed]

Adams, R. J.

There are two methodological shortcomings in the studies of R. J. Adams, D. Maurer, M. Davis [“Newborns’ discrimination of chromatic from achromatic stimuli,” J. Exp. Child Psychol. 41, 267–281 (1986)] and D. Maurer, R. J. Adams [“Emergence of the ability to discriminate a blue from gray at one month of age,” J. Exp. Child Psychol. 44, 147–156 (1987)]. First and most important, they did not vary the intensity of their chromatic stimuli for each infant. Instead, different intensities were presented to different groups of children. If group looking times were, at all intensities, significantly greater to the chromatic checkerboards than to the uniform fields, they concluded that infants were able to differentiate on the basis of hue alone. If dips in performance were observed at particular check intensities, they concluded that infants based their responses on brightness cues. The validity of the former conclusion hinges on the untested assumption that equiluminant points are similar for all infants of a given age. If such points vary from child to child, the absence of performance dips does not rule out the possibility that some infants based their looking preferences on brightness at each stimulus intensity. Second, even if equiluminance did not vary significantly across children, the performance criterion of Maurer and Adams was much more lenient than that of Teller. Maurer and Adams required only that looking times be statistically significantly greater with the checkerboards than with the uniform field. Teller and colleagues52–56 required at least 70% correct performance from each infant at all stimulus intensities.
[CrossRef] [PubMed]

Ahumada, A. J.

There are no quantitative data on the geometry of the newborn cone lattice, but newborn cones are probably roughly triangularly arranged for the following reasons. Inner segment diameters are 64–96% of the cone-to-cone separation in newborns and 74–89% of the cone-to-cone spacing in adults.16 Thus newborn cones are packed approximately as tightly as are adult cones. Tightly packed lattices tend to adopt triangular (or hexagonal) geometries [A. J. Ahumada, A. Poirson, “Modelling the irregularity of the fovealor mosaic,” Invest. Ophthalmol. Vis. Sci. Suppl. 27, 94 (1986)]. Furthermore, the foveal cone lattice of newborn macques, a species whose retinal development mirrors that of humans, appears more triangular than rectangular [O. Packer, Department of Psychology, University of Washington, Seattle, Washington 98195 (personal communication 1988)]. We assumed for these reasons that the geometry of the newborn lattice is nearly triangular. It does appear, however, that the neonatal foveal cone lattice is somewhat less regular than that of the adult [O. Packer (personal communication, 1988)], but the functional consequences of a slightly irregular lattice are undoubtedly small for most of the tasks considered in this paper. It was shown [W. S. Geisler, K. D. Davila, “Ideal discriminators in spatial vision: two point stimuli,” J. Opt. Soc. Am. A 2, 1483–1492 (1985)], for example, that ideal vernier thresholds are unaffected by moderate changes in lattice regularity. The most-noticeable effects are probably on grating acuity, particularly when performance approaches the Nyquist limit of the receptor lattice [J. I. Yellott, “Consequences of spatially irregular sampling for reconstruction of photon noisy images,” Invest. Ophthalmol. Vis. Sci. Suppl. 28, 137 (1987)].
[CrossRef] [PubMed]

Aitsebaomo, A. P.

D. M. Levi, S. A. Klein, A. P. Aitsebaomo, “Vernier acuity, crowding, and cortical magnification,” Vision Res. 25, 963–977 (1985).
[CrossRef]

Alexander, K.

R. D. Hamer, K. Alexander, D. Y. Teller, “Rayleigh discriminations in young human infants,” Vision Res. 22, 575–588 (1984).
[CrossRef]

Allen, D.

D. Allen, P. J. Bennett, M. S. Banks, “Effects of luminance on FPL and VEP acuity in human infants,” Invest. Ophthalmol. Vis. Sci. Suppl. 28, 5 (1987); V. Dobson, D. Salem, J. B. Carson, “Visual acuity in infants—the effect of variations in stimulus luminance within the photopic range,” Invest. Ophthalmol. Vis. Sci. 24, 519–522 (1983).
[PubMed]

Anderson, S. J.

J. Crowell, M. S. Banks, S. J. Anderson, W. S. Geisler, “Physical limits of grating visibility: fovea and periphery,” Invest. Ophthalmol. Vis. Sci. Suppl. 29, 139 (1988).

Atkinson, J.

J. Atkinson, O. Braddick, K. Moar, “Development of contrast sensitivity over the first three months of life in the human infant,” Vision Res. 17, 1037–1044 (1977).
[CrossRef]

J. Atkinson, O. J. Braddick, “Development of optokinetic nystagmus in infants: an indicator of cortical binocularity?” in Eye Movements: Cognition and Visual Perception, D. F. Fisher, R. A. Monty, J. W. Senders, eds. (Erlbaum, Hillsdale, N.J., 1981), pp. 53–64; M. S. Banks, B. R. Stephens, E. E. Hartmann, “The development of basic mechanisms of pattern vision: spatial frequency channels,” J. Exp. Child Psychol. 40, 501–527 (1985); O. Braddick, J. Atkinson, “Sensory selectivity, attentional control, and cross-channel integration in early visual development,” in Perceptual Development in Infancy: The Minnesota Symposium on Child Psychology, A. Yonas, ed. (Erlbaum, Hillsdale, N.J., 1987), pp. 105–143; O. Braddick, J. Wattam-Bell, J. Atkinson, “Orientation-specific cortical responses develop in early infancy,” Nature 320, 617–619 (1986).
[CrossRef] [PubMed]

Banks, M. S.

J. Crowell, M. S. Banks, S. J. Anderson, W. S. Geisler, “Physical limits of grating visibility: fovea and periphery,” Invest. Ophthalmol. Vis. Sci. Suppl. 29, 139 (1988).

M. S. Banks, W. S. Geisler, P. J. Bennett, “The physical limits of grating visibility,” Vision Res. 27, 1915–1924 (1987).
[CrossRef] [PubMed]

D. Allen, P. J. Bennett, M. S. Banks, “Effects of luminance on FPL and VEP acuity in human infants,” Invest. Ophthalmol. Vis. Sci. Suppl. 28, 5 (1987); V. Dobson, D. Salem, J. B. Carson, “Visual acuity in infants—the effect of variations in stimulus luminance within the photopic range,” Invest. Ophthalmol. Vis. Sci. 24, 519–522 (1983).
[PubMed]

J. L. Dannemiller, M. S. Banks, “The development of light adaptation in human infants,” Vision Res. 23, 599–609 (1983); R. M. Hansen, A. B. Fulton, “Behavioral measurement of background adaptation in infants,” Invest. Ophthalmol. Vis. Sci. 21, 625–629 (1981).
[CrossRef] [PubMed]

We assume a luminance of 50 cd/m2for the estimates of pupil diameter. Brown et al.4 also calculated numerical apertures and concluded that the aperture is constant across age under conditions of full dark adaptation and at a luminance of −2.6 log cd/m2. They argued, however, that the aperture is higher in infants at 0.55 log cd/m2and higher. The latter conclusion apparently stems from their own measurements of pupil diameter. This conclusion is inconsistent with that of M. S. Banks, “The development of visual accommodation during early infancy,” Child Dev. 51, 646–666 (1980), who reported that adult pupil diameters are larger than those of 4- to 12-week-old infants at 0.9 log cd/m2. It is also inconsistent with the data for 1-month-old infants and consistent with the data for 2-month-old infants reported by Salapatek and Banks.14
[CrossRef] [PubMed]

M. S. Banks, P. Salapatek, “Acuity and contrast sensitivity in 1-, 2-, and 3-month-old human infants,” Invest. Ophthalmol. 17, 361–365 (1978); “Infant pattern vision: a new approach based on the contrast sensitivity function,” J. Exp. Child Psychol. 31, 1–45 (1981).
[PubMed]

P. Salapatek, M. S. Banks, “Infant sensory assessment: vision,” in Communicative and Cognitive Abilities: Early Behavioral Assessment, F. D. Minifie, L. L. Lloyd, eds. (University Park, Baltimore, Md., 1978).

M. S. Banks, J. L. Dannemiller, “Infant visual psychophysics,” in Handbook of Infant Perception, P. Salapatek, L. B. Cohen, eds. (Academic, New York, 1987), pp. 115–184.

Barlow, H. B.

H. B. Barlow, “Temporal and spatial summation in human vision at different background intensities,” J. Physiol. 141, 337–350 (1958).

Bennett, P. J.

M. S. Banks, W. S. Geisler, P. J. Bennett, “The physical limits of grating visibility,” Vision Res. 27, 1915–1924 (1987).
[CrossRef] [PubMed]

D. Allen, P. J. Bennett, M. S. Banks, “Effects of luminance on FPL and VEP acuity in human infants,” Invest. Ophthalmol. Vis. Sci. Suppl. 28, 5 (1987); V. Dobson, D. Salem, J. B. Carson, “Visual acuity in infants—the effect of variations in stimulus luminance within the photopic range,” Invest. Ophthalmol. Vis. Sci. 24, 519–522 (1983).
[PubMed]

Bernard, G. D.

W. H. Miller, G. D. Bernard, “Averaging over the foveal receptor aperture curtails aliasing,” Vision Res. 23, 1365–1370 (1983).
[CrossRef] [PubMed]

Birch, E. E.

S. Shimojo, E. E. Birch, J. Gwiazda, R. Held, “Development of vernier acuity in infants,” Vision Res. 24, 721–728 (1984).
[CrossRef] [PubMed]

Blakemore, C.

D. S. Jacobs, C. Blakemore, “Factors limiting the postnatal development of visual acuity in the monkey,” Vision Res. 28, 947–958 (1988).
[CrossRef] [PubMed]

C. Blakemore, F. W. Campbell, “On the existence of neurons in the human visual system selectively sensitive to the orientation and size of retinal images,” J. Physiol. 203, 237–260 (1969);F. W. Campbell, J. J. Kulikowski, “Orientational selectivity of the human visual system,” J. Physiol. 187, 437–445 (1966).

Bonds, A. B.

A. B. Bonds, “Development of orientation tuning in the visual cortex of kittens,” in Developmental Neurobiology of Vision, R. D. Freeman, ed. (Plenum, New York, 1979); A. M. Derrington, A. F. Fuchs, “The development of spatial-frequency selectivity in kitten striate cortex,” J. Physiol. 316, 1–10 (1981);D. H. Hubel, T. N. Wiesel, “Receptive fields of cells in striate cortex of very young, visually inexperienced kittens,” J. Neurophysiol. 26, 994–1002 (1963).
[CrossRef] [PubMed]

Bone, R. A.

R. A. Bone, J. T. Landrum, L. Fernandez, S. L. Tarsis, “Analysis of macular pigment by HPLC: retinal distribution and age study,” Invest. Ophthalmol. Vis. Sci. 29, 843–849 (1988); J. S. Werner, “Development of scotopic sensitivity and the absorption spectrum of the human ocular media,” J. Opt. Soc. Am. 72, 247–258 (1982). We did not incorporate absorption by retinal structures anterior to the receptors even though the inner nuclear and ganglion cell layers overlay the receptor layer of the central fovea at birth (see Refs. 16 and 20).
[CrossRef] [PubMed]

Boothe, R. G.

Here we give the details of this argument. R. A. Williams, R. G. Boothe [“Development of optical quality in the infant monkey (Macaca nemestrina) eye,” Invest. Ophthalmol. Vis. Sci. 21, 728–736 (1981)] measured OTF’s in infant and adult Macaca nemestina, a species whose visual system at maturity is in many respects similar to the human adult system. Williams and Boothe found that optical transfer is only slightly poorer at birth than in adulthood. They concluded, consequently, that the optical quality of the young macaque eye greatly exceeds the resolution performance of the system as a whole. We do not know whether the optical quality of the human neonate’s eye is similar to that of the macaque newborn’s eye, but we can estimate the possible contributions of each of several possible optical imperfections: diffraction caused by the pupil, spherical aberration, chromatic aberration, and the clarity of the optic media. Optical degradation as a result of pupillary diffraction should be similar in newborns and adults because their numerical apertures are similar. In regard to spherical and chromatic aberration, unreasonably large amounts would be needed to constrain performance at spatial frequencies of 2 cycles/deg and less. The ocular media could be a significant limit if they were particularly turgid, but ophthalmoloscopic examination reveals clear media in the normal neonate [see, e.g., R. C. Cook, R. E. Glasscock, “Refractive and ocular findings in the newborn,” Am. J. Ophthalmol. 34, 1407–1413 (1951)]. Consequently, pupillary diffraction, spherical and chromatic aberrations, and media clarity probably do not impose significant constraints on early visual performance. Early spatial vision might be constrained by another optical error: inaccurate accommodation. This hypothesis is reasonable because accommodation, like acuity, improves notably during the first months of life.18 If accommodative error were an important limitation, one would expect the acuity of neonates to vary with target distance. On the contrary, several investigators showed that grating acuity does not vary with distance [See Ref. 22; P. Salapatek, A. G. Bechtold, E. W. Bushnell, “Infant visual acuity as a function of viewing distance,” Child Dev. 47, 860–863 (1976)]. Thus inaccurate accommodation does not appear to be a significant limitation to neonatal acuity and contrast sensitivity. In sum, the quality of the retinal image almost certainly surpasses the resolution performance of the young visual system. This state of affairs is reminiscent of the retinal periphery in the mature eye.23 Unlike those in the fovea, peripheral optics are superior to the spatial grain of the receptor lattice. Consequently, adults are able to detect aliasing under conventional viewing conditions [R. A. Smith, P. F. Cass, “Aliasing in the parafovea with incoherent light,” J. Opt. Soc. Am. A 4, 1530–1534 (1987); L. N. Thibos, D. J. Walsh, F. E. Cheney, “Vision beyond the resolution limit: aliasing in the periphery,” Vision Res. 27, 2193–2197 (1987)]. This raises the intriguing possibility that young infants can detect alias in everyday viewing.
[CrossRef] [PubMed]

Bornstein, M. H.

D. Y. Teller, M. H. Bornstein, “Infant color vision,” in Handbook of Infant Perception, P. Salapatek, L. B. Cohen, eds. (Academic, New York, 1978), pp. 185–236.

Bouman, M. A.

Bowen, R. W.

V. C. Smith, R. W. Bowen, J. Pokorny, “Threshold temporal integration of chromatic stimuli,” Vision Res. 24, 653–660 (1984).
[CrossRef] [PubMed]

Braddick, O.

J. Atkinson, O. Braddick, K. Moar, “Development of contrast sensitivity over the first three months of life in the human infant,” Vision Res. 17, 1037–1044 (1977).
[CrossRef]

Braddick, O. J.

J. Atkinson, O. J. Braddick, “Development of optokinetic nystagmus in infants: an indicator of cortical binocularity?” in Eye Movements: Cognition and Visual Perception, D. F. Fisher, R. A. Monty, J. W. Senders, eds. (Erlbaum, Hillsdale, N.J., 1981), pp. 53–64; M. S. Banks, B. R. Stephens, E. E. Hartmann, “The development of basic mechanisms of pattern vision: spatial frequency channels,” J. Exp. Child Psychol. 40, 501–527 (1985); O. Braddick, J. Atkinson, “Sensory selectivity, attentional control, and cross-channel integration in early visual development,” in Perceptual Development in Infancy: The Minnesota Symposium on Child Psychology, A. Yonas, ed. (Erlbaum, Hillsdale, N.J., 1987), pp. 105–143; O. Braddick, J. Wattam-Bell, J. Atkinson, “Orientation-specific cortical responses develop in early infancy,” Nature 320, 617–619 (1986).
[CrossRef] [PubMed]

Brickwedde, F. G.

Bronson, G.

G. Bronson, “The postnatal growth of visual capacity,” Child Dev. 45, 873–890 (1974); P. Salapatek, “Pattern perception in early infancy,” in Infant Perception: From Sensation to Cognition, L. B. Cohen, P. Salapatek, eds. (Academic, New York, 1975), pp. 133–248.
[CrossRef] [PubMed]

Brown, A. M.

A. M. Brown, V. Dobson, J. Maier, “Visual acuity of human infants at scotopic, mesopic, and photopic luminances,” Vision Res. 27, 1845–1858 (1987).
[CrossRef]

Campbell, F. W.

C. Blakemore, F. W. Campbell, “On the existence of neurons in the human visual system selectively sensitive to the orientation and size of retinal images,” J. Physiol. 203, 237–260 (1969);F. W. Campbell, J. J. Kulikowski, “Orientational selectivity of the human visual system,” J. Physiol. 187, 437–445 (1966).

F. W. Campbell, J. G. Robson, “Application of Fourier analysis to the visibility of gratings,” J. Physiol. 197, 551–556 (1968).

F. W. Campbell, R. W. Gubisch, “Optical quality of the human eye,” J. Physiol. 186, 558–578 (1966).

Cole, G. R.

C. F. Stromeyer, G. R. Cole, R. E. Kronauer, “Second-site adaptation in the red-green chromatic pathways,” Vision Res. 25, 219–238 (1985).
[CrossRef] [PubMed]

Cook, J. E.

D. Varner, J. E. Cook, M. E. Schneck, M. A. McDonald, D. Y. Teller, “Tritan discrimination by 1- and 2-month-old human infants,” Vision Res. 25, 821–831 (1985).
[CrossRef]

Crowell, J.

J. Crowell, M. S. Banks, S. J. Anderson, W. S. Geisler, “Physical limits of grating visibility: fovea and periphery,” Invest. Ophthalmol. Vis. Sci. Suppl. 29, 139 (1988).

Dannemiller, J. L.

J. L. Dannemiller, M. S. Banks, “The development of light adaptation in human infants,” Vision Res. 23, 599–609 (1983); R. M. Hansen, A. B. Fulton, “Behavioral measurement of background adaptation in infants,” Invest. Ophthalmol. Vis. Sci. 21, 625–629 (1981).
[CrossRef] [PubMed]

M. S. Banks, J. L. Dannemiller, “Infant visual psychophysics,” in Handbook of Infant Perception, P. Salapatek, L. B. Cohen, eds. (Academic, New York, 1987), pp. 115–184.

Davis, M.

There are two methodological shortcomings in the studies of R. J. Adams, D. Maurer, M. Davis [“Newborns’ discrimination of chromatic from achromatic stimuli,” J. Exp. Child Psychol. 41, 267–281 (1986)] and D. Maurer, R. J. Adams [“Emergence of the ability to discriminate a blue from gray at one month of age,” J. Exp. Child Psychol. 44, 147–156 (1987)]. First and most important, they did not vary the intensity of their chromatic stimuli for each infant. Instead, different intensities were presented to different groups of children. If group looking times were, at all intensities, significantly greater to the chromatic checkerboards than to the uniform fields, they concluded that infants were able to differentiate on the basis of hue alone. If dips in performance were observed at particular check intensities, they concluded that infants based their responses on brightness cues. The validity of the former conclusion hinges on the untested assumption that equiluminant points are similar for all infants of a given age. If such points vary from child to child, the absence of performance dips does not rule out the possibility that some infants based their looking preferences on brightness at each stimulus intensity. Second, even if equiluminance did not vary significantly across children, the performance criterion of Maurer and Adams was much more lenient than that of Teller. Maurer and Adams required only that looking times be statistically significantly greater with the checkerboards than with the uniform field. Teller and colleagues52–56 required at least 70% correct performance from each infant at all stimulus intensities.
[CrossRef] [PubMed]

Derrington, A. M.

A. M. Derrington, J. Krauskopf, P. Lennie, “Chromatic mechanisms in lateral geniculate nucleus of macaque,” J. Physiol. 357, 241–265 (1984);R. L. De Valois, I. Abramov, G. H. Jacobs, “Analysis of response patterns of LGN cells,” J. Opt. Soc. Am. 56, 966–977 (1966).
[CrossRef] [PubMed]

Dobson, V.

A. M. Brown, V. Dobson, J. Maier, “Visual acuity of human infants at scotopic, mesopic, and photopic luminances,” Vision Res. 27, 1845–1858 (1987).
[CrossRef]

I. Abramov, J. Gordon, A. Hendrickson, L. Hainline, V. Dobson, E. LaBossiere, “The retina of the newborn human infant,” Science 217, 265–267 (1982); L. Bach, R. Seefelder, Atlas zur Entwicklungsgeschichte des Menschlichen Auges (Englemann, Leipzig, Germany, 1914).
[CrossRef] [PubMed]

V. Dobson, D. Y. Teller, “Visual acuity in human infants: a review and comparison of behavioral and electrophysiological techniques,” Vision Res. 18, 1469–1483 (1978).
[CrossRef]

Estevez, O.

O. Estevez, “On the fundamental data-base of normal and dichromatic color vision,” doctoral dissertation (University of Amsterdam, Amsterdam, The Netherlands, 1979).

Fernandez, L.

R. A. Bone, J. T. Landrum, L. Fernandez, S. L. Tarsis, “Analysis of macular pigment by HPLC: retinal distribution and age study,” Invest. Ophthalmol. Vis. Sci. 29, 843–849 (1988); J. S. Werner, “Development of scotopic sensitivity and the absorption spectrum of the human ocular media,” J. Opt. Soc. Am. 72, 247–258 (1982). We did not incorporate absorption by retinal structures anterior to the receptors even though the inner nuclear and ganglion cell layers overlay the receptor layer of the central fovea at birth (see Refs. 16 and 20).
[CrossRef] [PubMed]

Fiorentini, A.

M. Pirchio, D. Spinelli, A. Fiorentini, L. Maffei, “Infant contrast sensitivity evaluated by evoked potentials,” Brain Res. 141, 179–184 (1978); A. M. Norcia, C. W. Tyler, D. Allen, “Electrophysiological assessment of contrast sensitivity in human infants,” Am. J. Optom. Physiol. Opt. 63, 12–15 (1986).
[CrossRef] [PubMed]

Flynn, J. T.

D. I. Hamasaki, J. T. Flynn, “Physiological properties of retinal ganglion cells of 3-week-old kittens,” Vision Res. 17, 275–284 (1977).
[CrossRef] [PubMed]

Geisler, W. S.

J. Crowell, M. S. Banks, S. J. Anderson, W. S. Geisler, “Physical limits of grating visibility: fovea and periphery,” Invest. Ophthalmol. Vis. Sci. Suppl. 29, 139 (1988).

M. S. Banks, W. S. Geisler, P. J. Bennett, “The physical limits of grating visibility,” Vision Res. 27, 1915–1924 (1987).
[CrossRef] [PubMed]

W. S. Geisler, “Physical limits of acuity and hyperacuity,” J. Opt. Soc. Am. A 1, 775–782 (1984).
[CrossRef] [PubMed]

W. S. Geisler, “Sequential ideal-observer analysis of visual discriminations,” Psychol. Rev. (to be published).

This idea was suggested by W. S. Geisler, Department of Psychology, University of Texas, Austin, Texas 78712 (personal communication, 1988).

Gelb, D. J.

Gordon, J.

I. Abramov, J. Gordon, A. Hendrickson, L. Hainline, V. Dobson, E. LaBossiere, “The retina of the newborn human infant,” Science 217, 265–267 (1982); L. Bach, R. Seefelder, Atlas zur Entwicklungsgeschichte des Menschlichen Auges (Englemann, Leipzig, Germany, 1914).
[CrossRef] [PubMed]

Granger, E. M.

Green, D. G.

D. G. Green, “Regional variations in the visual acuity for interference fringes on the retina,” J. Physiol. 207, 351–356 (1970);D. R. Williams, “Aliasing in human foveal vision,” Vision Res. 25, 195–205 (1985).
[CrossRef] [PubMed]

Gubisch, R. W.

F. W. Campbell, R. W. Gubisch, “Optical quality of the human eye,” J. Physiol. 186, 558–578 (1966).

Gwiazda, J.

S. Shimojo, E. E. Birch, J. Gwiazda, R. Held, “Development of vernier acuity in infants,” Vision Res. 24, 721–728 (1984).
[CrossRef] [PubMed]

Hainline, L.

Two pieces of evidence suggest, but by no means prove, that newborns fixate visual targets foveally: (1) Neonates seem to use a consistent retinal locus when fixating a high-contrast target [Ref. 3; L. Hainline, C. Harris, “Does foveal development influence the consistency of infants’ point of visual regard?” Infant Behav. Dev. 11, 129 (1988); A. M. Slater, J. M. Findlay, “Binocular fixation in the newborn baby,” J. Exp. Child Psychol. 20, 248–273 (1975)]. It was not demonstrated, however, that this locus is the fovea because of uncertainties about the location of the visual axis with respect to the optic axis. (2) Retinal and central nervous development in macaques and humans is similar, except that macaques are somewhat more advanced at birth and mature more rapidly [R. G. Boothe, R. A. Williams, L. Kiorpes, D. Y. Teller, “Development of contrast sensitivity in infant Macaca nemestrina monkeys,” Science 208, 1290–1292 (1980); P. M. Kiely, S. G. Crewther, J. Nathan, N. A. Brennan, N. Efron, M. Madigan, “A comparison of ocular development of the cynomolgus monkey and man,” Clin. Vis. Sci. 3, 269–280 (1987); Ref. 30]. C. Blakemore, F. Vital-Durand [“Development of the neural basis of visual acuity in monkeys. Speculation on the origin of deprivation amblyopia,” Trans. Ophthalmol. Soc. U.K. 99, 363–368 (1980)] measured the visual resolution of lateral geniculate nucleus cells supplied by different retinal regions. They found much higher resolution among cells supplied by the fovea than among cells supplied by the periphery in 21-week-old and adult macaques. In newborn macaques, the acuity of foveal cells was diminished but still higher than the acuity of peripheral cells. Thus, in macaque infants anyway, the highest resolution is likely to be observed with central vision. The same appears to be true for human infants. T. L. Lewis, D. Maurer, D. Kay [“Newborns’ central vision: whole or hole?” J. Exp. Child Psychol. 26, 193–203 (1978)] found that newborns could detect a narrower light bar against a dark background when it was presented in central vision than when it was presented in the periphery. These pieces of evidence suggest that newborn contrast sensitivity and acuity estimates are manifestations of central rather than peripheral processing, but more direct experimental evidence clearly is needed to settle the issue.
[CrossRef] [PubMed]

I. Abramov, J. Gordon, A. Hendrickson, L. Hainline, V. Dobson, E. LaBossiere, “The retina of the newborn human infant,” Science 217, 265–267 (1982); L. Bach, R. Seefelder, Atlas zur Entwicklungsgeschichte des Menschlichen Auges (Englemann, Leipzig, Germany, 1914).
[CrossRef] [PubMed]

Hamasaki, D. I.

D. I. Hamasaki, J. T. Flynn, “Physiological properties of retinal ganglion cells of 3-week-old kittens,” Vision Res. 17, 275–284 (1977).
[CrossRef] [PubMed]

Hamer, R. D.

R. D. Hamer, M. E. Schneck, “Spatial summation in dark-adapted human infants,” Vision Res. 24, 77–85 (1984); A. B. Fulton, R. M. Hansen, C. W. Tyler, “Temporal summation in human infants,” Invest. Ophthalmol. Vis. Sci. Suppl. 29, 60 (1988).
[CrossRef] [PubMed]

R. D. Hamer, K. Alexander, D. Y. Teller, “Rayleigh discriminations in young human infants,” Vision Res. 22, 575–588 (1984).
[CrossRef]

Harris, C.

Two pieces of evidence suggest, but by no means prove, that newborns fixate visual targets foveally: (1) Neonates seem to use a consistent retinal locus when fixating a high-contrast target [Ref. 3; L. Hainline, C. Harris, “Does foveal development influence the consistency of infants’ point of visual regard?” Infant Behav. Dev. 11, 129 (1988); A. M. Slater, J. M. Findlay, “Binocular fixation in the newborn baby,” J. Exp. Child Psychol. 20, 248–273 (1975)]. It was not demonstrated, however, that this locus is the fovea because of uncertainties about the location of the visual axis with respect to the optic axis. (2) Retinal and central nervous development in macaques and humans is similar, except that macaques are somewhat more advanced at birth and mature more rapidly [R. G. Boothe, R. A. Williams, L. Kiorpes, D. Y. Teller, “Development of contrast sensitivity in infant Macaca nemestrina monkeys,” Science 208, 1290–1292 (1980); P. M. Kiely, S. G. Crewther, J. Nathan, N. A. Brennan, N. Efron, M. Madigan, “A comparison of ocular development of the cynomolgus monkey and man,” Clin. Vis. Sci. 3, 269–280 (1987); Ref. 30]. C. Blakemore, F. Vital-Durand [“Development of the neural basis of visual acuity in monkeys. Speculation on the origin of deprivation amblyopia,” Trans. Ophthalmol. Soc. U.K. 99, 363–368 (1980)] measured the visual resolution of lateral geniculate nucleus cells supplied by different retinal regions. They found much higher resolution among cells supplied by the fovea than among cells supplied by the periphery in 21-week-old and adult macaques. In newborn macaques, the acuity of foveal cells was diminished but still higher than the acuity of peripheral cells. Thus, in macaque infants anyway, the highest resolution is likely to be observed with central vision. The same appears to be true for human infants. T. L. Lewis, D. Maurer, D. Kay [“Newborns’ central vision: whole or hole?” J. Exp. Child Psychol. 26, 193–203 (1978)] found that newborns could detect a narrower light bar against a dark background when it was presented in central vision than when it was presented in the periphery. These pieces of evidence suggest that newborn contrast sensitivity and acuity estimates are manifestations of central rather than peripheral processing, but more direct experimental evidence clearly is needed to settle the issue.
[CrossRef] [PubMed]

Hartmann, E. E.

O. Packer, E. E. Hartmann, D. Y. Teller, “Infant color vision: the effect of test field size on Rayleigh discriminations,” Vision Res. 24, 1247–1260 (1984).
[CrossRef] [PubMed]

Held, R.

S. Shimojo, R. Held, “Vernier acuity is less than grating acuity in 2- and 3-month-olds,” Vision Res. 27, 77–86 (1987).
[CrossRef] [PubMed]

S. Shimojo, E. E. Birch, J. Gwiazda, R. Held, “Development of vernier acuity in infants,” Vision Res. 24, 721–728 (1984).
[CrossRef] [PubMed]

Hendrickson, A.

C. Yuodelis, A. Hendrickson, “A qualitative and quantitative analysis of the human fovea during development,” Vision Res. 26, 847–855 (1986).
[CrossRef] [PubMed]

A. Hendrickson, C. Yuodelis, “The morphological development of the human fovea,” Ophthalmologica 91, 603–612 (1984).

I. Abramov, J. Gordon, A. Hendrickson, L. Hainline, V. Dobson, E. LaBossiere, “The retina of the newborn human infant,” Science 217, 265–267 (1982); L. Bach, R. Seefelder, Atlas zur Entwicklungsgeschichte des Menschlichen Auges (Englemann, Leipzig, Germany, 1914).
[CrossRef] [PubMed]

The same ratio was used at all ages for two reasons: (1) The few existing data suggest that all the cones are present before birth [Ref. 16; A. Hendrickson, C. Kupfer, “The histogenesis of the fovea in the macaque monkey,” Invest. Ophthalmol. 15, 746–756 (1976)], so it is unlikely that the proportion of different cone types changes postnatally. It remains possible, however, that one or more cone types are present but dysfunctional early in life, in which case the proportions of functional cones may differ from our assumption. (2) Throughout this paper we have adopted the strategy of assuming that newborn properties are adultlike unless there are data to the contrary.

Hess, R. F.

E. R. Howell, R. F. Hess, “The functional area for summation to threshold for sinusoidal gratings,” Vision Res. 18, 369–374 (1978); J. J. Koenderink, M. A. Bouman, A. E. Bueno de Mesquita, S. Slappendel, “Perimetry of contrast detection thresholds of moving spatial sine wave patterns. III. The target extent as a sensitivity controlling parameter,” J. Opt. Soc. Am. 68, 854–860 (1978).
[CrossRef] [PubMed]

Heurtley, J. C.

Hirano, S.

Most of the growth of the eye occurs in the first year. Axial length, for instance, is 16–17 mm at birth, 20–21 mm at 1 year, and 23–25 mm in adolescence and adulthood [see Ref. 13; S. Hirano, Y. Yamamoto, H. Takayama, Y. Sugata, K. Matsuo, “Ultrasonic observations of eyes in premature babies. Part 6: growth curves of ocular axial length and its components,” Acta Soc. Ophthalmol. Jpn. 83, 1679–1693 (1979)]. Image magnification is proportional to posterior nodal distance [A. G. Bennett, J. L. Francis, “Aberrations of optical images,” in The Eye, H. Davson, ed. (Academic, New York, 1962)], and so calculations of age-related changes in magnification require estimates of the nodal distance at different ages. The only schematic eyes described for the newborn [J. M. Enoch, R. D. Hamer, “Image size correction of the unilateral aphakic infant,” Ophthalmol. Pediatr. Genet. 2, 153–165 (1983); W. Lotmar, “A theoretical model for the eye of new-born infants,” Albrecht von Graefes Archiv. Klin. Exp. Ophthalmol. 198, 179–185 (1976)] have posterior nodal distances of 10.3–12.0 mm, roughly 2/3 of the adult distance. For a given target in space, then, retinal image size in the eye of the newborn infant should be 2/3 of that in the mature eye. Stated another way, a 1-deg target should subtend 204 μ m on the retina of a newborn infant and 298 μ m on the retina of an adult.
[CrossRef]

Hood, D. C.

D. C. Hood, “Sensitivity to light,” in Handbook of Perception and Human Performance, K. R. Boff, L. Kaufman, J. P. Thomas, eds. (Wiley, New York, 1986), pp. 5-1–5-66. The equation that we used to calculate half-bleaching constants is(1−p)/T0=I[1−exp(−Dp)]/(DQe), where p is the proportion of unbleached pigment, T0is the regeneration time constant, I is the steady retinal illuminance in trolands, D is the optical density, and Qe is the photosensitivity of the receptor in troland-seconds. The half-bleaching constants reported in the text should be modified slightly to reflect the differences in effective apertures of newborn and adult cones. If we make the assumption that 80% of the quanta incident upon the adult inner segment are transmitted to the outer segment, the adult half-bleaching illuminance is reduced by 0.3 log unit relative to the newborn value.

Howell, E. R.

E. R. Howell, R. F. Hess, “The functional area for summation to threshold for sinusoidal gratings,” Vision Res. 18, 369–374 (1978); J. J. Koenderink, M. A. Bouman, A. E. Bueno de Mesquita, S. Slappendel, “Perimetry of contrast detection thresholds of moving spatial sine wave patterns. III. The target extent as a sensitivity controlling parameter,” J. Opt. Soc. Am. 68, 854–860 (1978).
[CrossRef] [PubMed]

Jacobs, D. S.

D. S. Jacobs, C. Blakemore, “Factors limiting the postnatal development of visual acuity in the monkey,” Vision Res. 28, 947–958 (1988).
[CrossRef] [PubMed]

Kelly, D. H.

D. H. Kelly, “Visual contrast sensitivity,” Opt. Acta 24, 107–129 (1977).
[CrossRef]

Kiorpes, L.

Klein, S. A.

D. M. Levi, S. A. Klein, A. P. Aitsebaomo, “Vernier acuity, crowding, and cortical magnification,” Vision Res. 25, 963–977 (1985).
[CrossRef]

R. E. Manny, S. A. Klein, “A three-alternative tracking paradigm to measure vernier acuity of older infants,” Vision Res. 25, 1245–1252 (1985).
[CrossRef]

R. E. Manny, S. A. Klein, “The development of vernier acuity in infants,” Curr. Eye Res. 3, 453–462 (1984).
[CrossRef] [PubMed]

D. M. Levi, S. A. Klein, “Hyperacuity and amblyopia,” Nature 298, 268–270 (1982).
[CrossRef] [PubMed]

Krauskopf, J.

A. M. Derrington, J. Krauskopf, P. Lennie, “Chromatic mechanisms in lateral geniculate nucleus of macaque,” J. Physiol. 357, 241–265 (1984);R. L. De Valois, I. Abramov, G. H. Jacobs, “Analysis of response patterns of LGN cells,” J. Opt. Soc. Am. 56, 966–977 (1966).
[CrossRef] [PubMed]

Kronauer, R. E.

C. F. Stromeyer, G. R. Cole, R. E. Kronauer, “Second-site adaptation in the red-green chromatic pathways,” Vision Res. 25, 219–238 (1985).
[CrossRef] [PubMed]

Kupfer, C.

The same ratio was used at all ages for two reasons: (1) The few existing data suggest that all the cones are present before birth [Ref. 16; A. Hendrickson, C. Kupfer, “The histogenesis of the fovea in the macaque monkey,” Invest. Ophthalmol. 15, 746–756 (1976)], so it is unlikely that the proportion of different cone types changes postnatally. It remains possible, however, that one or more cone types are present but dysfunctional early in life, in which case the proportions of functional cones may differ from our assumption. (2) Throughout this paper we have adopted the strategy of assuming that newborn properties are adultlike unless there are data to the contrary.

LaBossiere, E.

I. Abramov, J. Gordon, A. Hendrickson, L. Hainline, V. Dobson, E. LaBossiere, “The retina of the newborn human infant,” Science 217, 265–267 (1982); L. Bach, R. Seefelder, Atlas zur Entwicklungsgeschichte des Menschlichen Auges (Englemann, Leipzig, Germany, 1914).
[CrossRef] [PubMed]

Landrum, J. T.

R. A. Bone, J. T. Landrum, L. Fernandez, S. L. Tarsis, “Analysis of macular pigment by HPLC: retinal distribution and age study,” Invest. Ophthalmol. Vis. Sci. 29, 843–849 (1988); J. S. Werner, “Development of scotopic sensitivity and the absorption spectrum of the human ocular media,” J. Opt. Soc. Am. 72, 247–258 (1982). We did not incorporate absorption by retinal structures anterior to the receptors even though the inner nuclear and ganglion cell layers overlay the receptor layer of the central fovea at birth (see Refs. 16 and 20).
[CrossRef] [PubMed]

Larsen, J. S.

J. S. Larsen, “The sagittal growth of the eye. IV. Ultrasonic measurement of the axial length of the eye from birth to puberty,” Acta Ophthalmol. 49, 873–886 (1971).
[CrossRef]

Lennie, P.

A. M. Derrington, J. Krauskopf, P. Lennie, “Chromatic mechanisms in lateral geniculate nucleus of macaque,” J. Physiol. 357, 241–265 (1984);R. L. De Valois, I. Abramov, G. H. Jacobs, “Analysis of response patterns of LGN cells,” J. Opt. Soc. Am. 56, 966–977 (1966).
[CrossRef] [PubMed]

Levi, D. M.

D. M. Levi, S. A. Klein, A. P. Aitsebaomo, “Vernier acuity, crowding, and cortical magnification,” Vision Res. 25, 963–977 (1985).
[CrossRef]

D. M. Levi, S. A. Klein, “Hyperacuity and amblyopia,” Nature 298, 268–270 (1982).
[CrossRef] [PubMed]

MacLeod, D. I. A.

D. I. A. MacLeod, “Visual sensitivity,” Annu. Rev. Psychol. 29, 613–645 (1978).
[CrossRef] [PubMed]

Maffei, L.

M. Pirchio, D. Spinelli, A. Fiorentini, L. Maffei, “Infant contrast sensitivity evaluated by evoked potentials,” Brain Res. 141, 179–184 (1978); A. M. Norcia, C. W. Tyler, D. Allen, “Electrophysiological assessment of contrast sensitivity in human infants,” Am. J. Optom. Physiol. Opt. 63, 12–15 (1986).
[CrossRef] [PubMed]

Maier, J.

A. M. Brown, V. Dobson, J. Maier, “Visual acuity of human infants at scotopic, mesopic, and photopic luminances,” Vision Res. 27, 1845–1858 (1987).
[CrossRef]

Manny, R. E.

R. E. Manny, S. A. Klein, “A three-alternative tracking paradigm to measure vernier acuity of older infants,” Vision Res. 25, 1245–1252 (1985).
[CrossRef]

R. E. Manny, S. A. Klein, “The development of vernier acuity in infants,” Curr. Eye Res. 3, 453–462 (1984).
[CrossRef] [PubMed]

Matsuo, K.

Most of the growth of the eye occurs in the first year. Axial length, for instance, is 16–17 mm at birth, 20–21 mm at 1 year, and 23–25 mm in adolescence and adulthood [see Ref. 13; S. Hirano, Y. Yamamoto, H. Takayama, Y. Sugata, K. Matsuo, “Ultrasonic observations of eyes in premature babies. Part 6: growth curves of ocular axial length and its components,” Acta Soc. Ophthalmol. Jpn. 83, 1679–1693 (1979)]. Image magnification is proportional to posterior nodal distance [A. G. Bennett, J. L. Francis, “Aberrations of optical images,” in The Eye, H. Davson, ed. (Academic, New York, 1962)], and so calculations of age-related changes in magnification require estimates of the nodal distance at different ages. The only schematic eyes described for the newborn [J. M. Enoch, R. D. Hamer, “Image size correction of the unilateral aphakic infant,” Ophthalmol. Pediatr. Genet. 2, 153–165 (1983); W. Lotmar, “A theoretical model for the eye of new-born infants,” Albrecht von Graefes Archiv. Klin. Exp. Ophthalmol. 198, 179–185 (1976)] have posterior nodal distances of 10.3–12.0 mm, roughly 2/3 of the adult distance. For a given target in space, then, retinal image size in the eye of the newborn infant should be 2/3 of that in the mature eye. Stated another way, a 1-deg target should subtend 204 μ m on the retina of a newborn infant and 298 μ m on the retina of an adult.
[CrossRef]

Maurer, D.

There are two methodological shortcomings in the studies of R. J. Adams, D. Maurer, M. Davis [“Newborns’ discrimination of chromatic from achromatic stimuli,” J. Exp. Child Psychol. 41, 267–281 (1986)] and D. Maurer, R. J. Adams [“Emergence of the ability to discriminate a blue from gray at one month of age,” J. Exp. Child Psychol. 44, 147–156 (1987)]. First and most important, they did not vary the intensity of their chromatic stimuli for each infant. Instead, different intensities were presented to different groups of children. If group looking times were, at all intensities, significantly greater to the chromatic checkerboards than to the uniform fields, they concluded that infants were able to differentiate on the basis of hue alone. If dips in performance were observed at particular check intensities, they concluded that infants based their responses on brightness cues. The validity of the former conclusion hinges on the untested assumption that equiluminant points are similar for all infants of a given age. If such points vary from child to child, the absence of performance dips does not rule out the possibility that some infants based their looking preferences on brightness at each stimulus intensity. Second, even if equiluminance did not vary significantly across children, the performance criterion of Maurer and Adams was much more lenient than that of Teller. Maurer and Adams required only that looking times be statistically significantly greater with the checkerboards than with the uniform field. Teller and colleagues52–56 required at least 70% correct performance from each infant at all stimulus intensities.
[CrossRef] [PubMed]

McDonald, M. A.

D. Varner, J. E. Cook, M. E. Schneck, M. A. McDonald, D. Y. Teller, “Tritan discrimination by 1- and 2-month-old human infants,” Vision Res. 25, 821–831 (1985).
[CrossRef]

Miller, W. H.

W. H. Miller, G. D. Bernard, “Averaging over the foveal receptor aperture curtails aliasing,” Vision Res. 23, 1365–1370 (1983).
[CrossRef] [PubMed]

Moar, K.

J. Atkinson, O. Braddick, K. Moar, “Development of contrast sensitivity over the first three months of life in the human infant,” Vision Res. 17, 1037–1044 (1977).
[CrossRef]

Movshon, J. A.

Mullen, K. T.

K. T. Mullen, “The contrast sensitivity of human color vision to red/green and blue/yellow chromatic gratings,” J. Physiol. 359, 381–400 (1985).

Norcia, A. M.

A. M. Norcia, C. W. Tyler, “Spatial frequency sweep VEP: visual acuity during the first year of life,” Vision Res. 25, 1399–1408 (1985).
[CrossRef] [PubMed]

A. M. Norcia, Smith-Kettlewell Institute, 2232 Webster Street, San Francisco, California 94115 (personal communication, 1988).

Packer, O.

O. Packer, E. E. Hartmann, D. Y. Teller, “Infant color vision: the effect of test field size on Rayleigh discriminations,” Vision Res. 24, 1247–1260 (1984).
[CrossRef] [PubMed]

Peeples, D. R.

D. Y. Teller, D. R. Peeples, M. Sekel, “Discrimination of chromatic from white light by two-month-old human infants,” Vision Res. 18, 41–48 (1978).
[CrossRef] [PubMed]

There is indirect evidence that all three cone types are functional at birth. D. R. Peeples, D. Y. Teller [“White-adapted photopic spectral sensitivity in human infants,” Vision Res. 18, 49–53 (1978)] and A. Moskowitz-Cook [“The development of photopic spectral sensitivity in human infants,” Vision Res. 18, 1133–1142 (1979)] showed that the photopic spectral sensitivity of infants is similar to that of adults. Their observations suggest that MWS and LWS cones are functional early in life. The small differences between neonatal and adult photopic spectral sensitivities probably are explained by age-related changes in the ocular media.19V. J. Volbrecht, J. S. Werner [“Isolation of short-wavelength-sensitive cone photoreceptors in 4–6-week-old human infants,” Vision Res. 27, 469–478 (1987)] used a chromatic adaptation paradigm to demonstrate the presence of SWS cones in young infants. Although the results of these three studies imply the existence of three functional cone types, they do not indicate whether the infant visual system can preserve and compare signals from one cone type to another. Moreover, the data of Volbrecht and Werner do not inform us about the relative sensitivity of SWS cones early in life.
[CrossRef] [PubMed]

D. R. Peeples, D. Y. Teller, “Color vision and brightness discrimination in two-month-old infants,” Science 189, 1102–1103 (1975).
[CrossRef]

Pelli, D. G.

Pirchio, M.

M. Pirchio, D. Spinelli, A. Fiorentini, L. Maffei, “Infant contrast sensitivity evaluated by evoked potentials,” Brain Res. 141, 179–184 (1978); A. M. Norcia, C. W. Tyler, D. Allen, “Electrophysiological assessment of contrast sensitivity in human infants,” Am. J. Optom. Physiol. Opt. 63, 12–15 (1986).
[CrossRef] [PubMed]

Poirson, A.

There are no quantitative data on the geometry of the newborn cone lattice, but newborn cones are probably roughly triangularly arranged for the following reasons. Inner segment diameters are 64–96% of the cone-to-cone separation in newborns and 74–89% of the cone-to-cone spacing in adults.16 Thus newborn cones are packed approximately as tightly as are adult cones. Tightly packed lattices tend to adopt triangular (or hexagonal) geometries [A. J. Ahumada, A. Poirson, “Modelling the irregularity of the fovealor mosaic,” Invest. Ophthalmol. Vis. Sci. Suppl. 27, 94 (1986)]. Furthermore, the foveal cone lattice of newborn macques, a species whose retinal development mirrors that of humans, appears more triangular than rectangular [O. Packer, Department of Psychology, University of Washington, Seattle, Washington 98195 (personal communication 1988)]. We assumed for these reasons that the geometry of the newborn lattice is nearly triangular. It does appear, however, that the neonatal foveal cone lattice is somewhat less regular than that of the adult [O. Packer (personal communication, 1988)], but the functional consequences of a slightly irregular lattice are undoubtedly small for most of the tasks considered in this paper. It was shown [W. S. Geisler, K. D. Davila, “Ideal discriminators in spatial vision: two point stimuli,” J. Opt. Soc. Am. A 2, 1483–1492 (1985)], for example, that ideal vernier thresholds are unaffected by moderate changes in lattice regularity. The most-noticeable effects are probably on grating acuity, particularly when performance approaches the Nyquist limit of the receptor lattice [J. I. Yellott, “Consequences of spatially irregular sampling for reconstruction of photon noisy images,” Invest. Ophthalmol. Vis. Sci. Suppl. 28, 137 (1987)].
[CrossRef] [PubMed]

Pokorny, J.

Polyak, S. L.

Our estimates of the diameter of the rod-free zone, the foveola, are based on the data of Ref. 16. The estimate for the adult is slightly larger than that of S. L. Polyak [The Retina (U. Chicago Press, Chicago, Ill., 1941)], who reported 1.7–2.0 deg, and much larger than that of G. Oesterberg [“Topography of the layer of rods and cones in the human retina,” Acta Ophthalmol. Suppl. 6, 1–102 (1935)], who reported 1.0 deg. We use the estimate from Ref. 16 because it was obtained with better histological techniques.

Priest, I. G.

Robson, J. G.

F. W. Campbell, J. G. Robson, “Application of Fourier analysis to the visibility of gratings,” J. Physiol. 197, 551–556 (1968).

Rose, A.

A. Rose, “The relative sensitivities of television pick-up tubes, photographic film, and the human eye,” Proc. IRE 30, 293–300 (1942).
[CrossRef]

Salapatek, P.

M. S. Banks, P. Salapatek, “Acuity and contrast sensitivity in 1-, 2-, and 3-month-old human infants,” Invest. Ophthalmol. 17, 361–365 (1978); “Infant pattern vision: a new approach based on the contrast sensitivity function,” J. Exp. Child Psychol. 31, 1–45 (1981).
[PubMed]

P. Salapatek, M. S. Banks, “Infant sensory assessment: vision,” in Communicative and Cognitive Abilities: Early Behavioral Assessment, F. D. Minifie, L. L. Lloyd, eds. (University Park, Baltimore, Md., 1978).

Schneck, M. E.

D. Varner, J. E. Cook, M. E. Schneck, M. A. McDonald, D. Y. Teller, “Tritan discrimination by 1- and 2-month-old human infants,” Vision Res. 25, 821–831 (1985).
[CrossRef]

R. D. Hamer, M. E. Schneck, “Spatial summation in dark-adapted human infants,” Vision Res. 24, 77–85 (1984); A. B. Fulton, R. M. Hansen, C. W. Tyler, “Temporal summation in human infants,” Invest. Ophthalmol. Vis. Sci. Suppl. 29, 60 (1988).
[CrossRef] [PubMed]

Sekel, M.

D. Y. Teller, D. R. Peeples, M. Sekel, “Discrimination of chromatic from white light by two-month-old human infants,” Vision Res. 18, 41–48 (1978).
[CrossRef] [PubMed]

Shimojo, S.

S. Shimojo, R. Held, “Vernier acuity is less than grating acuity in 2- and 3-month-olds,” Vision Res. 27, 77–86 (1987).
[CrossRef] [PubMed]

S. Shimojo, E. E. Birch, J. Gwiazda, R. Held, “Development of vernier acuity in infants,” Vision Res. 24, 721–728 (1984).
[CrossRef] [PubMed]

Smith, V. C.

Spinelli, D.

M. Pirchio, D. Spinelli, A. Fiorentini, L. Maffei, “Infant contrast sensitivity evaluated by evoked potentials,” Brain Res. 141, 179–184 (1978); A. M. Norcia, C. W. Tyler, D. Allen, “Electrophysiological assessment of contrast sensitivity in human infants,” Am. J. Optom. Physiol. Opt. 63, 12–15 (1986).
[CrossRef] [PubMed]

Stenstrom, S.

S. Stenstrom, “Investigation of the variation and the correlation of the optical elements of human eyes,” Am. J. Optom. 25, 5 (1946).

Stiles, W. S.

G. Wyszecki, W. S. Stiles, Color Science: Concepts and Methods, Quantitative Data, and Formulae (Wiley, New York, 1982).

Stromeyer, C. F.

C. F. Stromeyer, G. R. Cole, R. E. Kronauer, “Second-site adaptation in the red-green chromatic pathways,” Vision Res. 25, 219–238 (1985).
[CrossRef] [PubMed]

Sugata, Y.

Most of the growth of the eye occurs in the first year. Axial length, for instance, is 16–17 mm at birth, 20–21 mm at 1 year, and 23–25 mm in adolescence and adulthood [see Ref. 13; S. Hirano, Y. Yamamoto, H. Takayama, Y. Sugata, K. Matsuo, “Ultrasonic observations of eyes in premature babies. Part 6: growth curves of ocular axial length and its components,” Acta Soc. Ophthalmol. Jpn. 83, 1679–1693 (1979)]. Image magnification is proportional to posterior nodal distance [A. G. Bennett, J. L. Francis, “Aberrations of optical images,” in The Eye, H. Davson, ed. (Academic, New York, 1962)], and so calculations of age-related changes in magnification require estimates of the nodal distance at different ages. The only schematic eyes described for the newborn [J. M. Enoch, R. D. Hamer, “Image size correction of the unilateral aphakic infant,” Ophthalmol. Pediatr. Genet. 2, 153–165 (1983); W. Lotmar, “A theoretical model for the eye of new-born infants,” Albrecht von Graefes Archiv. Klin. Exp. Ophthalmol. 198, 179–185 (1976)] have posterior nodal distances of 10.3–12.0 mm, roughly 2/3 of the adult distance. For a given target in space, then, retinal image size in the eye of the newborn infant should be 2/3 of that in the mature eye. Stated another way, a 1-deg target should subtend 204 μ m on the retina of a newborn infant and 298 μ m on the retina of an adult.
[CrossRef]

Takayama, H.

Most of the growth of the eye occurs in the first year. Axial length, for instance, is 16–17 mm at birth, 20–21 mm at 1 year, and 23–25 mm in adolescence and adulthood [see Ref. 13; S. Hirano, Y. Yamamoto, H. Takayama, Y. Sugata, K. Matsuo, “Ultrasonic observations of eyes in premature babies. Part 6: growth curves of ocular axial length and its components,” Acta Soc. Ophthalmol. Jpn. 83, 1679–1693 (1979)]. Image magnification is proportional to posterior nodal distance [A. G. Bennett, J. L. Francis, “Aberrations of optical images,” in The Eye, H. Davson, ed. (Academic, New York, 1962)], and so calculations of age-related changes in magnification require estimates of the nodal distance at different ages. The only schematic eyes described for the newborn [J. M. Enoch, R. D. Hamer, “Image size correction of the unilateral aphakic infant,” Ophthalmol. Pediatr. Genet. 2, 153–165 (1983); W. Lotmar, “A theoretical model for the eye of new-born infants,” Albrecht von Graefes Archiv. Klin. Exp. Ophthalmol. 198, 179–185 (1976)] have posterior nodal distances of 10.3–12.0 mm, roughly 2/3 of the adult distance. For a given target in space, then, retinal image size in the eye of the newborn infant should be 2/3 of that in the mature eye. Stated another way, a 1-deg target should subtend 204 μ m on the retina of a newborn infant and 298 μ m on the retina of an adult.
[CrossRef]

Tarsis, S. L.

R. A. Bone, J. T. Landrum, L. Fernandez, S. L. Tarsis, “Analysis of macular pigment by HPLC: retinal distribution and age study,” Invest. Ophthalmol. Vis. Sci. 29, 843–849 (1988); J. S. Werner, “Development of scotopic sensitivity and the absorption spectrum of the human ocular media,” J. Opt. Soc. Am. 72, 247–258 (1982). We did not incorporate absorption by retinal structures anterior to the receptors even though the inner nuclear and ganglion cell layers overlay the receptor layer of the central fovea at birth (see Refs. 16 and 20).
[CrossRef] [PubMed]

Teller, D. Y.

D. Varner, J. E. Cook, M. E. Schneck, M. A. McDonald, D. Y. Teller, “Tritan discrimination by 1- and 2-month-old human infants,” Vision Res. 25, 821–831 (1985).
[CrossRef]

O. Packer, E. E. Hartmann, D. Y. Teller, “Infant color vision: the effect of test field size on Rayleigh discriminations,” Vision Res. 24, 1247–1260 (1984).
[CrossRef] [PubMed]

R. D. Hamer, K. Alexander, D. Y. Teller, “Rayleigh discriminations in young human infants,” Vision Res. 22, 575–588 (1984).
[CrossRef]

D. Y. Teller, D. R. Peeples, M. Sekel, “Discrimination of chromatic from white light by two-month-old human infants,” Vision Res. 18, 41–48 (1978).
[CrossRef] [PubMed]

There is indirect evidence that all three cone types are functional at birth. D. R. Peeples, D. Y. Teller [“White-adapted photopic spectral sensitivity in human infants,” Vision Res. 18, 49–53 (1978)] and A. Moskowitz-Cook [“The development of photopic spectral sensitivity in human infants,” Vision Res. 18, 1133–1142 (1979)] showed that the photopic spectral sensitivity of infants is similar to that of adults. Their observations suggest that MWS and LWS cones are functional early in life. The small differences between neonatal and adult photopic spectral sensitivities probably are explained by age-related changes in the ocular media.19V. J. Volbrecht, J. S. Werner [“Isolation of short-wavelength-sensitive cone photoreceptors in 4–6-week-old human infants,” Vision Res. 27, 469–478 (1987)] used a chromatic adaptation paradigm to demonstrate the presence of SWS cones in young infants. Although the results of these three studies imply the existence of three functional cone types, they do not indicate whether the infant visual system can preserve and compare signals from one cone type to another. Moreover, the data of Volbrecht and Werner do not inform us about the relative sensitivity of SWS cones early in life.
[CrossRef] [PubMed]

V. Dobson, D. Y. Teller, “Visual acuity in human infants: a review and comparison of behavioral and electrophysiological techniques,” Vision Res. 18, 1469–1483 (1978).
[CrossRef]

D. R. Peeples, D. Y. Teller, “Color vision and brightness discrimination in two-month-old infants,” Science 189, 1102–1103 (1975).
[CrossRef]

D. Y. Teller, M. H. Bornstein, “Infant color vision,” in Handbook of Infant Perception, P. Salapatek, L. B. Cohen, eds. (Academic, New York, 1978), pp. 185–236.

Tyler, C. W.

A. M. Norcia, C. W. Tyler, “Spatial frequency sweep VEP: visual acuity during the first year of life,” Vision Res. 25, 1399–1408 (1985).
[CrossRef] [PubMed]

van der Horst, G. J. C.

Varner, D.

D. Varner, J. E. Cook, M. E. Schneck, M. A. McDonald, D. Y. Teller, “Tritan discrimination by 1- and 2-month-old human infants,” Vision Res. 25, 821–831 (1985).
[CrossRef]

Walraven, P. L.

P. L. Walraven, “A closer look at the tritanopic convergence point,” Vision Res. 14, 1339–1343 (1974).
[CrossRef] [PubMed]

Watson, A.

A. Watson, “The ideal observer concept as a modeling tool,” in Frontiers of Visual Science: Proceedings of the 1985 Symposium (National Academy of Sciences, Washington, D.C., 1987), pp. 32–37.

Westheimer, G.

G. Westheimer, “The spatial grain of the perifoveal visual field,” Vision Res. 22, 157–162 (1982).
[CrossRef] [PubMed]

Williams, R. A.

Here we give the details of this argument. R. A. Williams, R. G. Boothe [“Development of optical quality in the infant monkey (Macaca nemestrina) eye,” Invest. Ophthalmol. Vis. Sci. 21, 728–736 (1981)] measured OTF’s in infant and adult Macaca nemestina, a species whose visual system at maturity is in many respects similar to the human adult system. Williams and Boothe found that optical transfer is only slightly poorer at birth than in adulthood. They concluded, consequently, that the optical quality of the young macaque eye greatly exceeds the resolution performance of the system as a whole. We do not know whether the optical quality of the human neonate’s eye is similar to that of the macaque newborn’s eye, but we can estimate the possible contributions of each of several possible optical imperfections: diffraction caused by the pupil, spherical aberration, chromatic aberration, and the clarity of the optic media. Optical degradation as a result of pupillary diffraction should be similar in newborns and adults because their numerical apertures are similar. In regard to spherical and chromatic aberration, unreasonably large amounts would be needed to constrain performance at spatial frequencies of 2 cycles/deg and less. The ocular media could be a significant limit if they were particularly turgid, but ophthalmoloscopic examination reveals clear media in the normal neonate [see, e.g., R. C. Cook, R. E. Glasscock, “Refractive and ocular findings in the newborn,” Am. J. Ophthalmol. 34, 1407–1413 (1951)]. Consequently, pupillary diffraction, spherical and chromatic aberrations, and media clarity probably do not impose significant constraints on early visual performance. Early spatial vision might be constrained by another optical error: inaccurate accommodation. This hypothesis is reasonable because accommodation, like acuity, improves notably during the first months of life.18 If accommodative error were an important limitation, one would expect the acuity of neonates to vary with target distance. On the contrary, several investigators showed that grating acuity does not vary with distance [See Ref. 22; P. Salapatek, A. G. Bechtold, E. W. Bushnell, “Infant visual acuity as a function of viewing distance,” Child Dev. 47, 860–863 (1976)]. Thus inaccurate accommodation does not appear to be a significant limitation to neonatal acuity and contrast sensitivity. In sum, the quality of the retinal image almost certainly surpasses the resolution performance of the young visual system. This state of affairs is reminiscent of the retinal periphery in the mature eye.23 Unlike those in the fovea, peripheral optics are superior to the spatial grain of the receptor lattice. Consequently, adults are able to detect aliasing under conventional viewing conditions [R. A. Smith, P. F. Cass, “Aliasing in the parafovea with incoherent light,” J. Opt. Soc. Am. A 4, 1530–1534 (1987); L. N. Thibos, D. J. Walsh, F. E. Cheney, “Vision beyond the resolution limit: aliasing in the periphery,” Vision Res. 27, 2193–2197 (1987)]. This raises the intriguing possibility that young infants can detect alias in everyday viewing.
[CrossRef] [PubMed]

Wilson, H. R.

Winston, R.

A completely rigorous treatment would require consideration of physical-optical principles such as diffraction. However, the geometric-optics model is quite accurate when the ratio of stimulus wavelength divided by inner segment diameter is less than 1.0 [R. Winston, “The visual receptor as a light collector,” in Vertebrate Photoreceptor Optics, J. M. Enoch, F. L. Tobey, eds. (Springer-Verlag, Berlin, 1981)]. The ratio is less than 0.1 for both central and foveal slope cones in the neonate, so the use of geometric optics is unlikely to distort estimates of the effective collecting areas.
[CrossRef]

Wyszecki, G.

G. Wyszecki, W. S. Stiles, Color Science: Concepts and Methods, Quantitative Data, and Formulae (Wiley, New York, 1982).

Yamamoto, Y.

Most of the growth of the eye occurs in the first year. Axial length, for instance, is 16–17 mm at birth, 20–21 mm at 1 year, and 23–25 mm in adolescence and adulthood [see Ref. 13; S. Hirano, Y. Yamamoto, H. Takayama, Y. Sugata, K. Matsuo, “Ultrasonic observations of eyes in premature babies. Part 6: growth curves of ocular axial length and its components,” Acta Soc. Ophthalmol. Jpn. 83, 1679–1693 (1979)]. Image magnification is proportional to posterior nodal distance [A. G. Bennett, J. L. Francis, “Aberrations of optical images,” in The Eye, H. Davson, ed. (Academic, New York, 1962)], and so calculations of age-related changes in magnification require estimates of the nodal distance at different ages. The only schematic eyes described for the newborn [J. M. Enoch, R. D. Hamer, “Image size correction of the unilateral aphakic infant,” Ophthalmol. Pediatr. Genet. 2, 153–165 (1983); W. Lotmar, “A theoretical model for the eye of new-born infants,” Albrecht von Graefes Archiv. Klin. Exp. Ophthalmol. 198, 179–185 (1976)] have posterior nodal distances of 10.3–12.0 mm, roughly 2/3 of the adult distance. For a given target in space, then, retinal image size in the eye of the newborn infant should be 2/3 of that in the mature eye. Stated another way, a 1-deg target should subtend 204 μ m on the retina of a newborn infant and 298 μ m on the retina of an adult.
[CrossRef]

Yuodelis, C.

C. Yuodelis, A. Hendrickson, “A qualitative and quantitative analysis of the human fovea during development,” Vision Res. 26, 847–855 (1986).
[CrossRef] [PubMed]

A. Hendrickson, C. Yuodelis, “The morphological development of the human fovea,” Ophthalmologica 91, 603–612 (1984).

Acta Ophthalmol. (1)

J. S. Larsen, “The sagittal growth of the eye. IV. Ultrasonic measurement of the axial length of the eye from birth to puberty,” Acta Ophthalmol. 49, 873–886 (1971).
[CrossRef]

Acta Soc. Ophthalmol. Jpn. (1)

Most of the growth of the eye occurs in the first year. Axial length, for instance, is 16–17 mm at birth, 20–21 mm at 1 year, and 23–25 mm in adolescence and adulthood [see Ref. 13; S. Hirano, Y. Yamamoto, H. Takayama, Y. Sugata, K. Matsuo, “Ultrasonic observations of eyes in premature babies. Part 6: growth curves of ocular axial length and its components,” Acta Soc. Ophthalmol. Jpn. 83, 1679–1693 (1979)]. Image magnification is proportional to posterior nodal distance [A. G. Bennett, J. L. Francis, “Aberrations of optical images,” in The Eye, H. Davson, ed. (Academic, New York, 1962)], and so calculations of age-related changes in magnification require estimates of the nodal distance at different ages. The only schematic eyes described for the newborn [J. M. Enoch, R. D. Hamer, “Image size correction of the unilateral aphakic infant,” Ophthalmol. Pediatr. Genet. 2, 153–165 (1983); W. Lotmar, “A theoretical model for the eye of new-born infants,” Albrecht von Graefes Archiv. Klin. Exp. Ophthalmol. 198, 179–185 (1976)] have posterior nodal distances of 10.3–12.0 mm, roughly 2/3 of the adult distance. For a given target in space, then, retinal image size in the eye of the newborn infant should be 2/3 of that in the mature eye. Stated another way, a 1-deg target should subtend 204 μ m on the retina of a newborn infant and 298 μ m on the retina of an adult.
[CrossRef]

Am. J. Optom. (1)

S. Stenstrom, “Investigation of the variation and the correlation of the optical elements of human eyes,” Am. J. Optom. 25, 5 (1946).

Annu. Rev. Psychol. (1)

D. I. A. MacLeod, “Visual sensitivity,” Annu. Rev. Psychol. 29, 613–645 (1978).
[CrossRef] [PubMed]

Brain Res. (1)

M. Pirchio, D. Spinelli, A. Fiorentini, L. Maffei, “Infant contrast sensitivity evaluated by evoked potentials,” Brain Res. 141, 179–184 (1978); A. M. Norcia, C. W. Tyler, D. Allen, “Electrophysiological assessment of contrast sensitivity in human infants,” Am. J. Optom. Physiol. Opt. 63, 12–15 (1986).
[CrossRef] [PubMed]

Child Dev. (2)

We assume a luminance of 50 cd/m2for the estimates of pupil diameter. Brown et al.4 also calculated numerical apertures and concluded that the aperture is constant across age under conditions of full dark adaptation and at a luminance of −2.6 log cd/m2. They argued, however, that the aperture is higher in infants at 0.55 log cd/m2and higher. The latter conclusion apparently stems from their own measurements of pupil diameter. This conclusion is inconsistent with that of M. S. Banks, “The development of visual accommodation during early infancy,” Child Dev. 51, 646–666 (1980), who reported that adult pupil diameters are larger than those of 4- to 12-week-old infants at 0.9 log cd/m2. It is also inconsistent with the data for 1-month-old infants and consistent with the data for 2-month-old infants reported by Salapatek and Banks.14
[CrossRef] [PubMed]

G. Bronson, “The postnatal growth of visual capacity,” Child Dev. 45, 873–890 (1974); P. Salapatek, “Pattern perception in early infancy,” in Infant Perception: From Sensation to Cognition, L. B. Cohen, P. Salapatek, eds. (Academic, New York, 1975), pp. 133–248.
[CrossRef] [PubMed]

Curr. Eye Res. (1)

R. E. Manny, S. A. Klein, “The development of vernier acuity in infants,” Curr. Eye Res. 3, 453–462 (1984).
[CrossRef] [PubMed]

Infant Behav. Dev. (1)

Two pieces of evidence suggest, but by no means prove, that newborns fixate visual targets foveally: (1) Neonates seem to use a consistent retinal locus when fixating a high-contrast target [Ref. 3; L. Hainline, C. Harris, “Does foveal development influence the consistency of infants’ point of visual regard?” Infant Behav. Dev. 11, 129 (1988); A. M. Slater, J. M. Findlay, “Binocular fixation in the newborn baby,” J. Exp. Child Psychol. 20, 248–273 (1975)]. It was not demonstrated, however, that this locus is the fovea because of uncertainties about the location of the visual axis with respect to the optic axis. (2) Retinal and central nervous development in macaques and humans is similar, except that macaques are somewhat more advanced at birth and mature more rapidly [R. G. Boothe, R. A. Williams, L. Kiorpes, D. Y. Teller, “Development of contrast sensitivity in infant Macaca nemestrina monkeys,” Science 208, 1290–1292 (1980); P. M. Kiely, S. G. Crewther, J. Nathan, N. A. Brennan, N. Efron, M. Madigan, “A comparison of ocular development of the cynomolgus monkey and man,” Clin. Vis. Sci. 3, 269–280 (1987); Ref. 30]. C. Blakemore, F. Vital-Durand [“Development of the neural basis of visual acuity in monkeys. Speculation on the origin of deprivation amblyopia,” Trans. Ophthalmol. Soc. U.K. 99, 363–368 (1980)] measured the visual resolution of lateral geniculate nucleus cells supplied by different retinal regions. They found much higher resolution among cells supplied by the fovea than among cells supplied by the periphery in 21-week-old and adult macaques. In newborn macaques, the acuity of foveal cells was diminished but still higher than the acuity of peripheral cells. Thus, in macaque infants anyway, the highest resolution is likely to be observed with central vision. The same appears to be true for human infants. T. L. Lewis, D. Maurer, D. Kay [“Newborns’ central vision: whole or hole?” J. Exp. Child Psychol. 26, 193–203 (1978)] found that newborns could detect a narrower light bar against a dark background when it was presented in central vision than when it was presented in the periphery. These pieces of evidence suggest that newborn contrast sensitivity and acuity estimates are manifestations of central rather than peripheral processing, but more direct experimental evidence clearly is needed to settle the issue.
[CrossRef] [PubMed]

Invest. Ophthalmol. (2)

M. S. Banks, P. Salapatek, “Acuity and contrast sensitivity in 1-, 2-, and 3-month-old human infants,” Invest. Ophthalmol. 17, 361–365 (1978); “Infant pattern vision: a new approach based on the contrast sensitivity function,” J. Exp. Child Psychol. 31, 1–45 (1981).
[PubMed]

The same ratio was used at all ages for two reasons: (1) The few existing data suggest that all the cones are present before birth [Ref. 16; A. Hendrickson, C. Kupfer, “The histogenesis of the fovea in the macaque monkey,” Invest. Ophthalmol. 15, 746–756 (1976)], so it is unlikely that the proportion of different cone types changes postnatally. It remains possible, however, that one or more cone types are present but dysfunctional early in life, in which case the proportions of functional cones may differ from our assumption. (2) Throughout this paper we have adopted the strategy of assuming that newborn properties are adultlike unless there are data to the contrary.

Invest. Ophthalmol. Vis. Sci. (2)

Here we give the details of this argument. R. A. Williams, R. G. Boothe [“Development of optical quality in the infant monkey (Macaca nemestrina) eye,” Invest. Ophthalmol. Vis. Sci. 21, 728–736 (1981)] measured OTF’s in infant and adult Macaca nemestina, a species whose visual system at maturity is in many respects similar to the human adult system. Williams and Boothe found that optical transfer is only slightly poorer at birth than in adulthood. They concluded, consequently, that the optical quality of the young macaque eye greatly exceeds the resolution performance of the system as a whole. We do not know whether the optical quality of the human neonate’s eye is similar to that of the macaque newborn’s eye, but we can estimate the possible contributions of each of several possible optical imperfections: diffraction caused by the pupil, spherical aberration, chromatic aberration, and the clarity of the optic media. Optical degradation as a result of pupillary diffraction should be similar in newborns and adults because their numerical apertures are similar. In regard to spherical and chromatic aberration, unreasonably large amounts would be needed to constrain performance at spatial frequencies of 2 cycles/deg and less. The ocular media could be a significant limit if they were particularly turgid, but ophthalmoloscopic examination reveals clear media in the normal neonate [see, e.g., R. C. Cook, R. E. Glasscock, “Refractive and ocular findings in the newborn,” Am. J. Ophthalmol. 34, 1407–1413 (1951)]. Consequently, pupillary diffraction, spherical and chromatic aberrations, and media clarity probably do not impose significant constraints on early visual performance. Early spatial vision might be constrained by another optical error: inaccurate accommodation. This hypothesis is reasonable because accommodation, like acuity, improves notably during the first months of life.18 If accommodative error were an important limitation, one would expect the acuity of neonates to vary with target distance. On the contrary, several investigators showed that grating acuity does not vary with distance [See Ref. 22; P. Salapatek, A. G. Bechtold, E. W. Bushnell, “Infant visual acuity as a function of viewing distance,” Child Dev. 47, 860–863 (1976)]. Thus inaccurate accommodation does not appear to be a significant limitation to neonatal acuity and contrast sensitivity. In sum, the quality of the retinal image almost certainly surpasses the resolution performance of the young visual system. This state of affairs is reminiscent of the retinal periphery in the mature eye.23 Unlike those in the fovea, peripheral optics are superior to the spatial grain of the receptor lattice. Consequently, adults are able to detect aliasing under conventional viewing conditions [R. A. Smith, P. F. Cass, “Aliasing in the parafovea with incoherent light,” J. Opt. Soc. Am. A 4, 1530–1534 (1987); L. N. Thibos, D. J. Walsh, F. E. Cheney, “Vision beyond the resolution limit: aliasing in the periphery,” Vision Res. 27, 2193–2197 (1987)]. This raises the intriguing possibility that young infants can detect alias in everyday viewing.
[CrossRef] [PubMed]

R. A. Bone, J. T. Landrum, L. Fernandez, S. L. Tarsis, “Analysis of macular pigment by HPLC: retinal distribution and age study,” Invest. Ophthalmol. Vis. Sci. 29, 843–849 (1988); J. S. Werner, “Development of scotopic sensitivity and the absorption spectrum of the human ocular media,” J. Opt. Soc. Am. 72, 247–258 (1982). We did not incorporate absorption by retinal structures anterior to the receptors even though the inner nuclear and ganglion cell layers overlay the receptor layer of the central fovea at birth (see Refs. 16 and 20).
[CrossRef] [PubMed]

Invest. Ophthalmol. Vis. Sci. Suppl. (3)

There are no quantitative data on the geometry of the newborn cone lattice, but newborn cones are probably roughly triangularly arranged for the following reasons. Inner segment diameters are 64–96% of the cone-to-cone separation in newborns and 74–89% of the cone-to-cone spacing in adults.16 Thus newborn cones are packed approximately as tightly as are adult cones. Tightly packed lattices tend to adopt triangular (or hexagonal) geometries [A. J. Ahumada, A. Poirson, “Modelling the irregularity of the fovealor mosaic,” Invest. Ophthalmol. Vis. Sci. Suppl. 27, 94 (1986)]. Furthermore, the foveal cone lattice of newborn macques, a species whose retinal development mirrors that of humans, appears more triangular than rectangular [O. Packer, Department of Psychology, University of Washington, Seattle, Washington 98195 (personal communication 1988)]. We assumed for these reasons that the geometry of the newborn lattice is nearly triangular. It does appear, however, that the neonatal foveal cone lattice is somewhat less regular than that of the adult [O. Packer (personal communication, 1988)], but the functional consequences of a slightly irregular lattice are undoubtedly small for most of the tasks considered in this paper. It was shown [W. S. Geisler, K. D. Davila, “Ideal discriminators in spatial vision: two point stimuli,” J. Opt. Soc. Am. A 2, 1483–1492 (1985)], for example, that ideal vernier thresholds are unaffected by moderate changes in lattice regularity. The most-noticeable effects are probably on grating acuity, particularly when performance approaches the Nyquist limit of the receptor lattice [J. I. Yellott, “Consequences of spatially irregular sampling for reconstruction of photon noisy images,” Invest. Ophthalmol. Vis. Sci. Suppl. 28, 137 (1987)].
[CrossRef] [PubMed]

J. Crowell, M. S. Banks, S. J. Anderson, W. S. Geisler, “Physical limits of grating visibility: fovea and periphery,” Invest. Ophthalmol. Vis. Sci. Suppl. 29, 139 (1988).

D. Allen, P. J. Bennett, M. S. Banks, “Effects of luminance on FPL and VEP acuity in human infants,” Invest. Ophthalmol. Vis. Sci. Suppl. 28, 5 (1987); V. Dobson, D. Salem, J. B. Carson, “Visual acuity in infants—the effect of variations in stimulus luminance within the photopic range,” Invest. Ophthalmol. Vis. Sci. 24, 519–522 (1983).
[PubMed]

J. Exp. Child Psychol. (1)

There are two methodological shortcomings in the studies of R. J. Adams, D. Maurer, M. Davis [“Newborns’ discrimination of chromatic from achromatic stimuli,” J. Exp. Child Psychol. 41, 267–281 (1986)] and D. Maurer, R. J. Adams [“Emergence of the ability to discriminate a blue from gray at one month of age,” J. Exp. Child Psychol. 44, 147–156 (1987)]. First and most important, they did not vary the intensity of their chromatic stimuli for each infant. Instead, different intensities were presented to different groups of children. If group looking times were, at all intensities, significantly greater to the chromatic checkerboards than to the uniform fields, they concluded that infants were able to differentiate on the basis of hue alone. If dips in performance were observed at particular check intensities, they concluded that infants based their responses on brightness cues. The validity of the former conclusion hinges on the untested assumption that equiluminant points are similar for all infants of a given age. If such points vary from child to child, the absence of performance dips does not rule out the possibility that some infants based their looking preferences on brightness at each stimulus intensity. Second, even if equiluminance did not vary significantly across children, the performance criterion of Maurer and Adams was much more lenient than that of Teller. Maurer and Adams required only that looking times be statistically significantly greater with the checkerboards than with the uniform field. Teller and colleagues52–56 required at least 70% correct performance from each infant at all stimulus intensities.
[CrossRef] [PubMed]

J. Opt. Soc. Am. (4)

I. G. Priest, F. G. Brickwedde, “The perceptible colorimetric purity as a function of dominant wavelength,” J. Opt. Soc. Am. 28, 133–139 (1938); W. D. Wright, Researches on Normal and Defective Colour Vision (Klimpton, London, 1946).
[CrossRef]

E. M. Granger, J. C. Heurtley, “Visual chromaticity modulation transfer function,” J. Opt. Soc. Am. 63, 1173–1174 (1973); D. H. Kelly, “Spatiotemporal variation of chromatic and achromatic contrast thresholds,” J. Opt. Soc. Am. 73, 742–750 (1983); G. J. C. van der Horst, C. M. M. de Weert, M. A. Bouman, “Transfer of spatial chromaticity-contrast at threshold in the human eye,” J. Opt. Soc. Am. 57, 1260–1266 (1967).
[CrossRef] [PubMed]

The ideal observer of Table 1 follows square-root law in chromatic contrast sensitivity tasks.G. J. C. van der Horst, M. A. Bouman [“Spatio-temporal chromaticity discrimination,” J. Opt. Soc. Am. 59, 1482–1488 (1969)] measured contrast sensitivity with isoluminant gratings for a wide range of photopic illuminances. They found that chromatic contrast sensitivity (defined in a fashion similar to that in Ref. 59) increased as the square-root of illuminance from 1.2 to 160 photopic trolands, the highest light level presented. Square-root law only held for frequencies greater than 3 cycles/deg; at lower frequencies, Weber’s law was observed at the higher illuminances. Thus, as with luminance contrast sensitivity,32,33 the luminance dependence of ideal chromatic contrast sensitivity is similar to that of real observers, at least for intermediate to high spatial frequencies.
[CrossRef] [PubMed]

Because neonatal outer segments are shorter than adult segments, they probably exhibit less self-screening.67 In consequence, neonatal action spectra should be narrower than adult spectra. We have not incorporated this effect into the newborn ideal observer because it is likely to be quite small for the tasks that we consider. It should be noted, however, that the narrowing of action spectra should cause the color-matching and luminosity functions of neonates to differ from those of adults. For instance, one would predict that the green–red setting in an anomaloscopelike experiment would be lower in infants’ central vision just as it is in adults’ peripheral vision [J. Pokorny, V. C. Smith, “Effect of field size on red–green color mixture equations,” J. Opt. Soc. Am. 66, 705–708 (1976)]. In addition, one would predict the relative luminous efficiency of long-wavelength lights to be lower in neonates’ central vision. Interestingly, Hamer et al.,54 Packer et al.,55 and J. E. Clavadetscher [“Young infants show a relative insensitivity to long wavelength (red) light,” Infant Behav. Dev. Suppl.11, (1988)] reported such an effect in young infants.
[CrossRef] [PubMed]

J. Opt. Soc. Am. A (4)

J. Physiol. (7)

C. Blakemore, F. W. Campbell, “On the existence of neurons in the human visual system selectively sensitive to the orientation and size of retinal images,” J. Physiol. 203, 237–260 (1969);F. W. Campbell, J. J. Kulikowski, “Orientational selectivity of the human visual system,” J. Physiol. 187, 437–445 (1966).

H. B. Barlow, “Temporal and spatial summation in human vision at different background intensities,” J. Physiol. 141, 337–350 (1958).

F. W. Campbell, J. G. Robson, “Application of Fourier analysis to the visibility of gratings,” J. Physiol. 197, 551–556 (1968).

D. G. Green, “Regional variations in the visual acuity for interference fringes on the retina,” J. Physiol. 207, 351–356 (1970);D. R. Williams, “Aliasing in human foveal vision,” Vision Res. 25, 195–205 (1985).
[CrossRef] [PubMed]

F. W. Campbell, R. W. Gubisch, “Optical quality of the human eye,” J. Physiol. 186, 558–578 (1966).

A. M. Derrington, J. Krauskopf, P. Lennie, “Chromatic mechanisms in lateral geniculate nucleus of macaque,” J. Physiol. 357, 241–265 (1984);R. L. De Valois, I. Abramov, G. H. Jacobs, “Analysis of response patterns of LGN cells,” J. Opt. Soc. Am. 56, 966–977 (1966).
[CrossRef] [PubMed]

K. T. Mullen, “The contrast sensitivity of human color vision to red/green and blue/yellow chromatic gratings,” J. Physiol. 359, 381–400 (1985).

Nature (1)

D. M. Levi, S. A. Klein, “Hyperacuity and amblyopia,” Nature 298, 268–270 (1982).
[CrossRef] [PubMed]

Ophthalmologica (1)

A. Hendrickson, C. Yuodelis, “The morphological development of the human fovea,” Ophthalmologica 91, 603–612 (1984).

Opt. Acta (1)

D. H. Kelly, “Visual contrast sensitivity,” Opt. Acta 24, 107–129 (1977).
[CrossRef]

Proc. IRE (1)

A. Rose, “The relative sensitivities of television pick-up tubes, photographic film, and the human eye,” Proc. IRE 30, 293–300 (1942).
[CrossRef]

Science (2)

I. Abramov, J. Gordon, A. Hendrickson, L. Hainline, V. Dobson, E. LaBossiere, “The retina of the newborn human infant,” Science 217, 265–267 (1982); L. Bach, R. Seefelder, Atlas zur Entwicklungsgeschichte des Menschlichen Auges (Englemann, Leipzig, Germany, 1914).
[CrossRef] [PubMed]

D. R. Peeples, D. Y. Teller, “Color vision and brightness discrimination in two-month-old infants,” Science 189, 1102–1103 (1975).
[CrossRef]

Vision Res. (26)

D. Y. Teller, D. R. Peeples, M. Sekel, “Discrimination of chromatic from white light by two-month-old human infants,” Vision Res. 18, 41–48 (1978).
[CrossRef] [PubMed]

R. D. Hamer, K. Alexander, D. Y. Teller, “Rayleigh discriminations in young human infants,” Vision Res. 22, 575–588 (1984).
[CrossRef]

O. Packer, E. E. Hartmann, D. Y. Teller, “Infant color vision: the effect of test field size on Rayleigh discriminations,” Vision Res. 24, 1247–1260 (1984).
[CrossRef] [PubMed]

D. Varner, J. E. Cook, M. E. Schneck, M. A. McDonald, D. Y. Teller, “Tritan discrimination by 1- and 2-month-old human infants,” Vision Res. 25, 821–831 (1985).
[CrossRef]

R. E. Manny, S. A. Klein, “A three-alternative tracking paradigm to measure vernier acuity of older infants,” Vision Res. 25, 1245–1252 (1985).
[CrossRef]

S. Shimojo, E. E. Birch, J. Gwiazda, R. Held, “Development of vernier acuity in infants,” Vision Res. 24, 721–728 (1984).
[CrossRef] [PubMed]

D. M. Levi, S. A. Klein, A. P. Aitsebaomo, “Vernier acuity, crowding, and cortical magnification,” Vision Res. 25, 963–977 (1985).
[CrossRef]

G. Westheimer, “The spatial grain of the perifoveal visual field,” Vision Res. 22, 157–162 (1982).
[CrossRef] [PubMed]

V. Dobson, D. Y. Teller, “Visual acuity in human infants: a review and comparison of behavioral and electrophysiological techniques,” Vision Res. 18, 1469–1483 (1978).
[CrossRef]

A. M. Norcia, C. W. Tyler, “Spatial frequency sweep VEP: visual acuity during the first year of life,” Vision Res. 25, 1399–1408 (1985).
[CrossRef] [PubMed]

C. F. Stromeyer, G. R. Cole, R. E. Kronauer, “Second-site adaptation in the red-green chromatic pathways,” Vision Res. 25, 219–238 (1985).
[CrossRef] [PubMed]

V. C. Smith, R. W. Bowen, J. Pokorny, “Threshold temporal integration of chromatic stimuli,” Vision Res. 24, 653–660 (1984).
[CrossRef] [PubMed]

There is indirect evidence that all three cone types are functional at birth. D. R. Peeples, D. Y. Teller [“White-adapted photopic spectral sensitivity in human infants,” Vision Res. 18, 49–53 (1978)] and A. Moskowitz-Cook [“The development of photopic spectral sensitivity in human infants,” Vision Res. 18, 1133–1142 (1979)] showed that the photopic spectral sensitivity of infants is similar to that of adults. Their observations suggest that MWS and LWS cones are functional early in life. The small differences between neonatal and adult photopic spectral sensitivities probably are explained by age-related changes in the ocular media.19V. J. Volbrecht, J. S. Werner [“Isolation of short-wavelength-sensitive cone photoreceptors in 4–6-week-old human infants,” Vision Res. 27, 469–478 (1987)] used a chromatic adaptation paradigm to demonstrate the presence of SWS cones in young infants. Although the results of these three studies imply the existence of three functional cone types, they do not indicate whether the infant visual system can preserve and compare signals from one cone type to another. Moreover, the data of Volbrecht and Werner do not inform us about the relative sensitivity of SWS cones early in life.
[CrossRef] [PubMed]

R. D. Hamer, M. E. Schneck, “Spatial summation in dark-adapted human infants,” Vision Res. 24, 77–85 (1984); A. B. Fulton, R. M. Hansen, C. W. Tyler, “Temporal summation in human infants,” Invest. Ophthalmol. Vis. Sci. Suppl. 29, 60 (1988).
[CrossRef] [PubMed]

C. Yuodelis, A. Hendrickson, “A qualitative and quantitative analysis of the human fovea during development,” Vision Res. 26, 847–855 (1986).
[CrossRef] [PubMed]

W. H. Miller, G. D. Bernard, “Averaging over the foveal receptor aperture curtails aliasing,” Vision Res. 23, 1365–1370 (1983).
[CrossRef] [PubMed]

D. S. Jacobs, C. Blakemore, “Factors limiting the postnatal development of visual acuity in the monkey,” Vision Res. 28, 947–958 (1988).
[CrossRef] [PubMed]

H. R. Wilson, “Development of spatiotemporal mechanisms in infant vision,” Vision Res. 28, 611–628 (1988).
[CrossRef] [PubMed]

A. M. Brown, V. Dobson, J. Maier, “Visual acuity of human infants at scotopic, mesopic, and photopic luminances,” Vision Res. 27, 1845–1858 (1987).
[CrossRef]

S. Shimojo, R. Held, “Vernier acuity is less than grating acuity in 2- and 3-month-olds,” Vision Res. 27, 77–86 (1987).
[CrossRef] [PubMed]

J. Atkinson, O. Braddick, K. Moar, “Development of contrast sensitivity over the first three months of life in the human infant,” Vision Res. 17, 1037–1044 (1977).
[CrossRef]

P. L. Walraven, “A closer look at the tritanopic convergence point,” Vision Res. 14, 1339–1343 (1974).
[CrossRef] [PubMed]

M. S. Banks, W. S. Geisler, P. J. Bennett, “The physical limits of grating visibility,” Vision Res. 27, 1915–1924 (1987).
[CrossRef] [PubMed]

E. R. Howell, R. F. Hess, “The functional area for summation to threshold for sinusoidal gratings,” Vision Res. 18, 369–374 (1978); J. J. Koenderink, M. A. Bouman, A. E. Bueno de Mesquita, S. Slappendel, “Perimetry of contrast detection thresholds of moving spatial sine wave patterns. III. The target extent as a sensitivity controlling parameter,” J. Opt. Soc. Am. 68, 854–860 (1978).
[CrossRef] [PubMed]

J. L. Dannemiller, M. S. Banks, “The development of light adaptation in human infants,” Vision Res. 23, 599–609 (1983); R. M. Hansen, A. B. Fulton, “Behavioral measurement of background adaptation in infants,” Invest. Ophthalmol. Vis. Sci. 21, 625–629 (1981).
[CrossRef] [PubMed]

D. I. Hamasaki, J. T. Flynn, “Physiological properties of retinal ganglion cells of 3-week-old kittens,” Vision Res. 17, 275–284 (1977).
[CrossRef] [PubMed]

Other (22)

This idea was suggested by W. S. Geisler, Department of Psychology, University of Texas, Austin, Texas 78712 (personal communication, 1988).

A. Watson, “The ideal observer concept as a modeling tool,” in Frontiers of Visual Science: Proceedings of the 1985 Symposium (National Academy of Sciences, Washington, D.C., 1987), pp. 32–37.

For a detailed discussion of the ideal observer that we used, see Refs. 7 and 8. The ideal observer has complete knowledge of the two stimuli to be discriminated and of the Poisson variability associated with them. From this, it constructs a tailored linear weighting function for the specific pair of stimuli. In the case of discriminating a Gabor patch from a uniform field, it constructs a weighting function (a receptive field) that is similar to but not identical to the Gabor patch itself. A stimulus is presented, and if the summed response across the weighted receptor outputs exceeds zero, the observer guesses that the Gabor patch was presented; otherwise it guesses that the uniform field was presented.

With small grating patches in a contrast discrimination task,33 sensitivity of the real observers is within a factor of 4 of ideal contrast sensitivity.

A. M. Norcia, Smith-Kettlewell Institute, 2232 Webster Street, San Francisco, California 94115 (personal communication, 1988).

O. Estevez, “On the fundamental data-base of normal and dichromatic color vision,” doctoral dissertation (University of Amsterdam, Amsterdam, The Netherlands, 1979).

Our estimates of the diameter of the rod-free zone, the foveola, are based on the data of Ref. 16. The estimate for the adult is slightly larger than that of S. L. Polyak [The Retina (U. Chicago Press, Chicago, Ill., 1941)], who reported 1.7–2.0 deg, and much larger than that of G. Oesterberg [“Topography of the layer of rods and cones in the human retina,” Acta Ophthalmol. Suppl. 6, 1–102 (1935)], who reported 1.0 deg. We use the estimate from Ref. 16 because it was obtained with better histological techniques.

A completely rigorous treatment would require consideration of physical-optical principles such as diffraction. However, the geometric-optics model is quite accurate when the ratio of stimulus wavelength divided by inner segment diameter is less than 1.0 [R. Winston, “The visual receptor as a light collector,” in Vertebrate Photoreceptor Optics, J. M. Enoch, F. L. Tobey, eds. (Springer-Verlag, Berlin, 1981)]. The ratio is less than 0.1 for both central and foveal slope cones in the neonate, so the use of geometric optics is unlikely to distort estimates of the effective collecting areas.
[CrossRef]

D. Y. Teller, M. H. Bornstein, “Infant color vision,” in Handbook of Infant Perception, P. Salapatek, L. B. Cohen, eds. (Academic, New York, 1978), pp. 185–236.

W. S. Geisler, “Sequential ideal-observer analysis of visual discriminations,” Psychol. Rev. (to be published).

P. Salapatek, M. S. Banks, “Infant sensory assessment: vision,” in Communicative and Cognitive Abilities: Early Behavioral Assessment, F. D. Minifie, L. L. Lloyd, eds. (University Park, Baltimore, Md., 1978).

J. Atkinson, O. J. Braddick, “Development of optokinetic nystagmus in infants: an indicator of cortical binocularity?” in Eye Movements: Cognition and Visual Perception, D. F. Fisher, R. A. Monty, J. W. Senders, eds. (Erlbaum, Hillsdale, N.J., 1981), pp. 53–64; M. S. Banks, B. R. Stephens, E. E. Hartmann, “The development of basic mechanisms of pattern vision: spatial frequency channels,” J. Exp. Child Psychol. 40, 501–527 (1985); O. Braddick, J. Atkinson, “Sensory selectivity, attentional control, and cross-channel integration in early visual development,” in Perceptual Development in Infancy: The Minnesota Symposium on Child Psychology, A. Yonas, ed. (Erlbaum, Hillsdale, N.J., 1987), pp. 105–143; O. Braddick, J. Wattam-Bell, J. Atkinson, “Orientation-specific cortical responses develop in early infancy,” Nature 320, 617–619 (1986).
[CrossRef] [PubMed]

A. B. Bonds, “Development of orientation tuning in the visual cortex of kittens,” in Developmental Neurobiology of Vision, R. D. Freeman, ed. (Plenum, New York, 1979); A. M. Derrington, A. F. Fuchs, “The development of spatial-frequency selectivity in kitten striate cortex,” J. Physiol. 316, 1–10 (1981);D. H. Hubel, T. N. Wiesel, “Receptive fields of cells in striate cortex of very young, visually inexperienced kittens,” J. Neurophysiol. 26, 994–1002 (1963).
[CrossRef] [PubMed]

D. C. Hood, “Sensitivity to light,” in Handbook of Perception and Human Performance, K. R. Boff, L. Kaufman, J. P. Thomas, eds. (Wiley, New York, 1986), pp. 5-1–5-66. The equation that we used to calculate half-bleaching constants is(1−p)/T0=I[1−exp(−Dp)]/(DQe), where p is the proportion of unbleached pigment, T0is the regeneration time constant, I is the steady retinal illuminance in trolands, D is the optical density, and Qe is the photosensitivity of the receptor in troland-seconds. The half-bleaching constants reported in the text should be modified slightly to reflect the differences in effective apertures of newborn and adult cones. If we make the assumption that 80% of the quanta incident upon the adult inner segment are transmitted to the outer segment, the adult half-bleaching illuminance is reduced by 0.3 log unit relative to the newborn value.

M. S. Banks, J. L. Dannemiller, “Infant visual psychophysics,” in Handbook of Infant Perception, P. Salapatek, L. B. Cohen, eds. (Academic, New York, 1987), pp. 115–184.

To understand this, it is useful to consider an isoluminant red–green grating separated into its two components: a red–black grating and a green–black grating. When the red component is presented, LWS cones respond in rough proportion to the luminance variation from the peak to the trough of the grating. They also respond in this way, though at somewhat reduced levels, to the green component. When the red and green grating components are added in phase, producing a yellow–black grating, the LWS cone modulations that are due to each component add, producing a large overall modulation. When the components are added in opposite phase, producing an isoluminant red–green grating, the LWS cone modulations to each component cancel to some degree, and the overall modulation is smaller. The same reasoning obviously applies to the MWS cones.

G. Wyszecki, W. S. Stiles, Color Science: Concepts and Methods, Quantitative Data, and Formulae (Wiley, New York, 1982).

For details on the ideal observer’s decision strategy in such tasks, consult Ref. 8. When asked to discriminate a 550-nm target in a 589-nm background from a uniform 589-nm background, the ideal observer constructs a weighting function consisting of positive weights for MWS cone stimulation in the target region and negative weights for LWS cone stimulation in the same region. When the summed response exceeds zero, the ideal observer guesses that the 550-nm target was presented.

Increment and decrement thresholds of real infants are nearly identical when expressed in log units.53

Some of the parameters of the neonatal ideal observer affect the predictions of the visual efficiency hypothesis and some do not. Pupil diameter, posterior nodal distance, receptor aperture, receptor spacing, the optical transfer function, and spatial summation area do not affect predictions at all because luminance and chromatic thresholds are affected similarly by changes in these parameters. Three parameters do influence predictions: (1) Ocular media transmittance: we assumed a higher transmittance for neonates.19 The media are nearly transparent at long wavelengths, so predictions for the Rayleigh54,55 and neutral-point52,53 experiments are virtually unaffected by the range of transmittances that we used. Predictions for the tritan experiment,56 however, are in fact affected by the media: the lighter the media, the lower the chromatic threshold of the neonatal ideal observer. (2) Relative numbers of the three cone types: within reasonable variations of the relative proportions of cone types, predictions do not vary significantly. (3) Outer segment length: self-screening affects the bandwidth of receptor absorption spectra.67 In long outer segments, self-screening is more pronounced and absorption spectra broaden. Thus neonatal foveal cones may well have narrower spectra than we assumed. The consequence of narrower spectra is an improvement in many chromatic discriminations relative to luminance discriminations. The effect is not large, however, for the chromatic tasks that we examined, so we do not incorporate it here.

We have examined how the parameters chosen for the neonatal ideal observer affect these results. Changes in most of the parameters cause only vertical shifting of the ideal CSF. These include pupil diameter, ocular media transmittance, and outer segment efficiency. Two other parameters cause nearly vertical shifting: receptor aperture and posterior nodal distance. Because ideal contrast sensitivity follows square-root law, an increase in any of these parameters (pupil area, media transmittance, etc.) by itself produces a square-root increase in sensitivity without affecting the shape of the CSF much, if at all. Outer segment efficiency and receptor aperture (which, along with receptor spacing, determines cone coverage) differ most between neonates and adults, so these parameters have by far the largest effects on the relative efficiency of the neonatal ideal observer. Two parameters, the OTF and the assumed spatial summation area, are the primary determinants of the shape of the ideal CSF. In both cases, we assumed adult values.21,34 Obviously, if optical transfer were significantly worse in neonatal eyes, the high-frequency roll-off of the ideal CSF would be steeper. If summation areas were constant (in degrees) across spatial frequency, the high-frequency roll-off would be shallower.

In retrospect, the data are not really consistent with this hypothesis because the failure to discriminate yellow-greens from yellowish-white is, if anything, more consistent with a protan or deutan defect.

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Figures (13)

Fig. 1
Fig. 1

Development of human foveal cones illustrated by light micrographs. A single cone is outlined in each figure; magnification in all figures is constant. Ages: six, 5 days postpartum; nine, 72 years. PE, Pigment epithelium; OPL, outer plexiform layer; M, Muller glial cell processes; CP, cone synaptic pedicles; OS, outer segments. (Reprinted from Ref. 16.)

Fig. 2
Fig. 2

Dimensions (in micrometers) and shapes used to model neonate and adult foveal cones. On the left is the model cone used for the central 250 μm of the neonate’s fovea. The inner segment is not tapered, in accord with the observations of Yuodelis and Hendrickson.16 In the middle is the model cone used for the foveal slope of the neonate. Again, the inner segment is untapered. On the right is the cone used to represent mature central foveal cones.

Fig. 3
Fig. 3

Schematics of the receptor lattices used in (a) neonatal and (b) adult ideal observers. The white bars represent 0.5 arcmin. Light gray areas represent the inner segments; dark gray areas represent effective collecting areas. The effective collecting areas cover 65% of the adult central fovea but only 2% of the newborn central fovea.

Fig. 4
Fig. 4

CSF of an ideal observer incorporating different properties of the human adult fovea. Contrast sensitivity is plotted against the spatial frequency of fixed-cycle sine-wave grating targets. The highest dashed curve shows the contrast sensitivity of an ideal machine limited by quantal noise, ocular media transmittance, and photoreceptor quantum efficiency. The slope of −1 is dependent on the use of sine-wave gratings of a constant number of cycles. Space-average luminance is 340 cd/m2. The lower dashed curve shows the contrast sensitivity with the receptor aperture effect added in. Finally, the highest solid curve shows the sensitivity with the optical transfer function added. The other solid curves represent the contrast sensitivities for 34 and 3.4 cd/m2 (from Ref. 32).

Fig. 5
Fig. 5

Empirically determined adult and infant CSF’s and the predicted loss of sensitivity caused by optical and receptoral factors. The curve labeled Neonate FPL is from Ref. 39 and was collected at 55 cd/m2. The curve labeled Neonate VEP is derived from data from Ref. 37. The VEP data were collected at a space-average luminance of 220 cd/cm2, so we shifted the function downward by 0.32 log unit to indicate its expected location at 50 cd/m2 (under the assumption that square-root law holds). The curve labeled Adult represents data from Ref. 38 that were collected at 50 cd/m2. Each vertical arrow represents the ratio of the ideal neonate sensitivity to the ideal adult sensitivity at each spatial frequency. The reductions in contrast sensitivity indicated by the arrows represent the effects of smaller image magnification, coarser spatial sampling by the cone lattice, and less-efficient photoreception in the neonate. The curves at the bottom of the arrows are the CSF’s that one would expect if adult and neonatal visual systems were identical except for the preneural factors listed in Tables 1 and 3.

Fig. 6
Fig. 6

CSF’s for ideal observers incorporating the preneural factors of the adult and neonatal central foveas and the neonatal foveal slope. As in Fig. 4, the stimuli were grating patches of a constant number of cycles, in order to incorporate changes in summation area with spatial frequency.32,34 Space-average luminance is 50 cd/m2. The differences between adult and neonatal sensitivities are due primarily to the reduced quantum capture of the neonate’s cone lattice.

Fig. 7
Fig. 7

Grating and vernier acuities as functions of age. The upper and lower panels illustrate data from Refs. 50 and 5, respectively. Acuity thresholds are plotted against age in weeks. Vernier thresholds are expressed as the just-detectable offsets in minutes of arc. Grating thresholds are expressed as the just-detectable stripe width in minutes. Thresholds in these experiments were measured by using the FPL procedure. High-contrast square-wave gratings were used for the grating experiments, and square-wave gratings with horizontal offsets were used for the vernier experiments.

Fig. 8
Fig. 8

Ideal grating and vernier acuity thresholds as a function of the proportion of incident photons absorbed. The stimuli were those of Ref. 5. Adult and newborn values are indicated by arrows. Space-average luminance was 100 cd/m2, and target duration was 100 msec. We used different summation areas for the two tasks: 6 cycles × 6 cycles in the case of grating acuity32,34 and 0.1 deg × 0.1 deg in the case of vernier acuity. The figure shows that ideal vernier thresholds are affected more by quantum efficiency than are ideal grating thresholds. These two results are manifestations of, on the one hand, the square-root relationship between the number of effective quanta and ideal vernier thresholds and, on the other hand, the roughly quarter-root relationship between quanta and ideal grating thresholds.

Fig. 9
Fig. 9

Adult vernier and grating acuities plotted against background luminance. The vernier acuity task was similar to that of Ref. 5 except that the spatial frequency of the grating was 6 cycles/deg. Vernier acuity, defined as the smallest visible offset, is represented by the filled circles. Grating acuity, defined as the half-period of the highest visible spatial frequency, is represented by the open squares. The grating data are from Ref. 4.

Fig. 10
Fig. 10

Real and ideal infant grating acuity as a function of luminance. The circles, triangles, and squares are from three different experiments.4,51 Open symbols represent data from FPL experiments, and filled symbols represent data from VEP experiments. The lowest solid curve represents the grating acuity of the neonatal ideal observer at various luminances. The other solid curves are shifted upward by 0.5 and 1.2 log units to facilitate shape comparisons.

Fig. 11
Fig. 11

Chromaticities of the stimuli used in the neutral-point experiments of Refs. 52 and 53. Subjects in both experiments were 8-week-old infants. Filled symbols represent stimuli that all infants reliably discriminated from white (W); open symbols represent hues that all infants failed to discriminate from white; half-filled symbols represent hues that some, but not all, infants discriminated from white. The dashed curve represents the boundary between hues that should and should not be discriminated from white according to the visual efficiency hypothesis. Hues falling outside the triangular area bounded by the dashed curve should be discriminable from white, and those falling within the area should not.

Fig. 12
Fig. 12

Data and predictions for the experiment of Ref. 55. Predicted Weber fractions are plotted as a function of age in weeks. Open symbols represent conditions in which infants did not reliably discriminate red from yellow (see Table 4 for stimulus details). Filled symbols represent conditions in which infants exhibited reliable discrimination, and half-filled symbols represent conditions in which some infants exhibited reliable discrimination and some did not. Target size is indicated by the symbol conventions displayed in the upper right. The dashed line represents the contrasts of the stimuli presented in this experiment. The vertical placement of the various symbols corresponds to the Weber fraction predicted by the visual efficiency hypothesis. Thus symbols above the dashed line represent conditions in which discrimination failures are predicted, and symbols below the line represent conditions in which reliable discrimination is predicted.

Fig. 13
Fig. 13

Data and predictions for the experiment of Ref. 54. Conventions are as described for Fig. 12 except that the different symbol shapes represent green-on-yellow discriminations and red-on-yellow discriminations.

Tables (4)

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Table 1 Ideal-Observer Parameters

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Table 2 Nyquist Limitsa

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Table 3 Outer Segment Efficiency

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Table 4 Results and Predictions for Color Experiments of Teller and Colleagues

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