Abstract

Defocus changes the visual contrast sensitivity function, thereby creating a complex curve with local dips and peaks. Since underwater vision in humans is severely defocused, we used optical theory and the phenomenon of spurious resolution to predict how well humans can see in this environment. The values obtained correspond well with experimental measurements of underwater human acuity from earlier studies and even point to an opportunity for humans with exceptional contrast sensitivity to see better underwater than the children in those studies. The same theory could be useful when discussing the visual acuity of amphibious animals, as they may use pupil constriction as a means of improving underwater vision.

© 2004 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. W. J. Smith, Modern Optical Engineering (McGraw-Hill, New York, 1966).
  2. N. C. Strang, D. A. Atchinson, R. L. Woods, “Effects of defocus and pupil size on human contrast sensitivity,” Ophthalmic Physiol. Opt. 19, 415–426 (1999).
    [CrossRef]
  3. R. L. Woods, N. C. Strang, D. A. Atchison, “Measuring contrast sensitivity with inappropriate optical correction,” Ophthalmic Physiol. Opt. 20, 442–451 (2000).
    [PubMed]
  4. A. Gislén, M. Dacke, R. H. H. Kröger, M. Abrahamson, D.-E. Nilsson, E. J. Warrant, “Superior underwater vision in a human population of sea-gypsies,” Curr. Biol. 13, 833–836 (2003).
    [CrossRef]
  5. A. Gislén, E. J. Warrant, R. H. H. Kröger, “Voluntary accommodation improves underwater vision in humans,” manuscript available from the authors (anna.gislen@cob.lu.se).
  6. A. Bradley, R. D. Freeman, “Contrast sensitivity in children,” Vision Res. 22, 953–959 (1982).
    [CrossRef] [PubMed]
  7. L. A. Olzak, J. P. Thomas, “Seeing spatial patterns,” in Handbook of Perception and Human Performance, K. R. Boff, L. Kaufman, J. P. Thomas, eds. (Wiley, New York, 1986), Chap. 7.
  8. J. Gwiazda, J. Bauer, F. Thorn, R. Held, “Development of spatial contrast sensitivity from infancy to adulthood: psychophysical data,” Optom. Vision Sci. 74, 785–789 (1997).
    [CrossRef]
  9. F. W. Campbell, J. G. Robson, “The application of Fourier analysis to the visibility of gratings,” J. Physiol. (London) 197, 551–566 (1968).
  10. K. K. De Valois, “Spatial frequency adaptation can enhance contrast sensitivity,” Vision Res. 17, 1057–1065 (1977).
    [CrossRef] [PubMed]
  11. P. T. Sowden, I. R. L. Davies, P. Roling, “Perceptual learning of the detection of features in X-ray images: a functional role for improvement in adults’ visual sensitivity?” J. Exp. Psychol. Hum. Percept. Perform. 26, 379–390 (2000).
    [CrossRef] [PubMed]
  12. P. T. Sowden, D. Rose, I. R. L. Davies, “Perceptual learning of luminance contrast detection: specific for spatial frequency and retinal location but not orientation,” Vision Res. 42, 1249–1258 (2002).
    [CrossRef] [PubMed]
  13. A. Gislén, M. Dacke, “A simple way to assess contrast sensitivity in children living in remote areas,” manuscript available from the authors (anna.gislen@cob.lu.se).
  14. H. Davson, Physiology of the Eye, 5th ed. (MacMillan, London, 1990), p. 830.
  15. E. Marg, M. W. Morgan, “The pupillary near reflex,” Am. J. Optom. Arch. Am. Acad. Optom. 26, 183–198 (1949).
    [CrossRef] [PubMed]
  16. F. Schaeffel, H. Wilhelm, E. Zrenner, “Inter-individual variability in the dynamics of natural accommodation in humans: relation to age and refractive errors,” J. Physiol. (London) 461, 301–320 (1993).
  17. N. Roth, “Effect of reduced retinal illuminance on the pupillary near reflex,” Vision Res. 9, 1259–1266 (1969).
    [CrossRef] [PubMed]
  18. J. G. Sivak, “A survey of vertebrate strategies for vision in air and water,” in Sensory Ecology, M. A. Ali, ed. (Plenum, New York, 1978), pp. 503–519.
  19. L. Herman, M. F. Peacock, M. P. Yunker, C. J. Madsen, “Bottlenose dolphin: double-slit pupil yields equivalent aerial and underwater diurnal activity,” Science 189, 650–652 (1975).
    [CrossRef] [PubMed]
  20. L. A. Rivamonte, “Eye model to account for comparable aerial and underwater acuities of the bottlenose dolphin,” Neth. J. Sea Res. 10, 491–498 (1976).
    [CrossRef]
  21. F. Schaeffel, “Underwater vision in semi-aquatic European snakes,” Naturwissenschaften 78, 373–375 (1991).
    [CrossRef]
  22. F. Schaeffel, A. De Queiroz, “Alternative mechanisms of enhanced underwater vision in the Garter snakes Thamnopsis melanogaster and T. couchii,” Copeia 1, 50–58 (1990).
    [CrossRef]
  23. F. Thorn, F. Schwartz, “Effects of dioptric blur on Snellen and grating acuity,” Optom. Vision Sci. 67, 3–7 (1990).
    [CrossRef]

2003 (1)

A. Gislén, M. Dacke, R. H. H. Kröger, M. Abrahamson, D.-E. Nilsson, E. J. Warrant, “Superior underwater vision in a human population of sea-gypsies,” Curr. Biol. 13, 833–836 (2003).
[CrossRef]

2002 (1)

P. T. Sowden, D. Rose, I. R. L. Davies, “Perceptual learning of luminance contrast detection: specific for spatial frequency and retinal location but not orientation,” Vision Res. 42, 1249–1258 (2002).
[CrossRef] [PubMed]

2000 (2)

R. L. Woods, N. C. Strang, D. A. Atchison, “Measuring contrast sensitivity with inappropriate optical correction,” Ophthalmic Physiol. Opt. 20, 442–451 (2000).
[PubMed]

P. T. Sowden, I. R. L. Davies, P. Roling, “Perceptual learning of the detection of features in X-ray images: a functional role for improvement in adults’ visual sensitivity?” J. Exp. Psychol. Hum. Percept. Perform. 26, 379–390 (2000).
[CrossRef] [PubMed]

1999 (1)

N. C. Strang, D. A. Atchinson, R. L. Woods, “Effects of defocus and pupil size on human contrast sensitivity,” Ophthalmic Physiol. Opt. 19, 415–426 (1999).
[CrossRef]

1997 (1)

J. Gwiazda, J. Bauer, F. Thorn, R. Held, “Development of spatial contrast sensitivity from infancy to adulthood: psychophysical data,” Optom. Vision Sci. 74, 785–789 (1997).
[CrossRef]

1993 (1)

F. Schaeffel, H. Wilhelm, E. Zrenner, “Inter-individual variability in the dynamics of natural accommodation in humans: relation to age and refractive errors,” J. Physiol. (London) 461, 301–320 (1993).

1991 (1)

F. Schaeffel, “Underwater vision in semi-aquatic European snakes,” Naturwissenschaften 78, 373–375 (1991).
[CrossRef]

1990 (2)

F. Schaeffel, A. De Queiroz, “Alternative mechanisms of enhanced underwater vision in the Garter snakes Thamnopsis melanogaster and T. couchii,” Copeia 1, 50–58 (1990).
[CrossRef]

F. Thorn, F. Schwartz, “Effects of dioptric blur on Snellen and grating acuity,” Optom. Vision Sci. 67, 3–7 (1990).
[CrossRef]

1982 (1)

A. Bradley, R. D. Freeman, “Contrast sensitivity in children,” Vision Res. 22, 953–959 (1982).
[CrossRef] [PubMed]

1977 (1)

K. K. De Valois, “Spatial frequency adaptation can enhance contrast sensitivity,” Vision Res. 17, 1057–1065 (1977).
[CrossRef] [PubMed]

1976 (1)

L. A. Rivamonte, “Eye model to account for comparable aerial and underwater acuities of the bottlenose dolphin,” Neth. J. Sea Res. 10, 491–498 (1976).
[CrossRef]

1975 (1)

L. Herman, M. F. Peacock, M. P. Yunker, C. J. Madsen, “Bottlenose dolphin: double-slit pupil yields equivalent aerial and underwater diurnal activity,” Science 189, 650–652 (1975).
[CrossRef] [PubMed]

1969 (1)

N. Roth, “Effect of reduced retinal illuminance on the pupillary near reflex,” Vision Res. 9, 1259–1266 (1969).
[CrossRef] [PubMed]

1968 (1)

F. W. Campbell, J. G. Robson, “The application of Fourier analysis to the visibility of gratings,” J. Physiol. (London) 197, 551–566 (1968).

1949 (1)

E. Marg, M. W. Morgan, “The pupillary near reflex,” Am. J. Optom. Arch. Am. Acad. Optom. 26, 183–198 (1949).
[CrossRef] [PubMed]

Abrahamson, M.

A. Gislén, M. Dacke, R. H. H. Kröger, M. Abrahamson, D.-E. Nilsson, E. J. Warrant, “Superior underwater vision in a human population of sea-gypsies,” Curr. Biol. 13, 833–836 (2003).
[CrossRef]

Atchinson, D. A.

N. C. Strang, D. A. Atchinson, R. L. Woods, “Effects of defocus and pupil size on human contrast sensitivity,” Ophthalmic Physiol. Opt. 19, 415–426 (1999).
[CrossRef]

Atchison, D. A.

R. L. Woods, N. C. Strang, D. A. Atchison, “Measuring contrast sensitivity with inappropriate optical correction,” Ophthalmic Physiol. Opt. 20, 442–451 (2000).
[PubMed]

Bauer, J.

J. Gwiazda, J. Bauer, F. Thorn, R. Held, “Development of spatial contrast sensitivity from infancy to adulthood: psychophysical data,” Optom. Vision Sci. 74, 785–789 (1997).
[CrossRef]

Bradley, A.

A. Bradley, R. D. Freeman, “Contrast sensitivity in children,” Vision Res. 22, 953–959 (1982).
[CrossRef] [PubMed]

Campbell, F. W.

F. W. Campbell, J. G. Robson, “The application of Fourier analysis to the visibility of gratings,” J. Physiol. (London) 197, 551–566 (1968).

Dacke, M.

A. Gislén, M. Dacke, R. H. H. Kröger, M. Abrahamson, D.-E. Nilsson, E. J. Warrant, “Superior underwater vision in a human population of sea-gypsies,” Curr. Biol. 13, 833–836 (2003).
[CrossRef]

A. Gislén, M. Dacke, “A simple way to assess contrast sensitivity in children living in remote areas,” manuscript available from the authors (anna.gislen@cob.lu.se).

Davies, I. R. L.

P. T. Sowden, D. Rose, I. R. L. Davies, “Perceptual learning of luminance contrast detection: specific for spatial frequency and retinal location but not orientation,” Vision Res. 42, 1249–1258 (2002).
[CrossRef] [PubMed]

P. T. Sowden, I. R. L. Davies, P. Roling, “Perceptual learning of the detection of features in X-ray images: a functional role for improvement in adults’ visual sensitivity?” J. Exp. Psychol. Hum. Percept. Perform. 26, 379–390 (2000).
[CrossRef] [PubMed]

Davson, H.

H. Davson, Physiology of the Eye, 5th ed. (MacMillan, London, 1990), p. 830.

De Queiroz, A.

F. Schaeffel, A. De Queiroz, “Alternative mechanisms of enhanced underwater vision in the Garter snakes Thamnopsis melanogaster and T. couchii,” Copeia 1, 50–58 (1990).
[CrossRef]

De Valois, K. K.

K. K. De Valois, “Spatial frequency adaptation can enhance contrast sensitivity,” Vision Res. 17, 1057–1065 (1977).
[CrossRef] [PubMed]

Freeman, R. D.

A. Bradley, R. D. Freeman, “Contrast sensitivity in children,” Vision Res. 22, 953–959 (1982).
[CrossRef] [PubMed]

Gislén, A.

A. Gislén, M. Dacke, R. H. H. Kröger, M. Abrahamson, D.-E. Nilsson, E. J. Warrant, “Superior underwater vision in a human population of sea-gypsies,” Curr. Biol. 13, 833–836 (2003).
[CrossRef]

A. Gislén, M. Dacke, “A simple way to assess contrast sensitivity in children living in remote areas,” manuscript available from the authors (anna.gislen@cob.lu.se).

A. Gislén, E. J. Warrant, R. H. H. Kröger, “Voluntary accommodation improves underwater vision in humans,” manuscript available from the authors (anna.gislen@cob.lu.se).

Gwiazda, J.

J. Gwiazda, J. Bauer, F. Thorn, R. Held, “Development of spatial contrast sensitivity from infancy to adulthood: psychophysical data,” Optom. Vision Sci. 74, 785–789 (1997).
[CrossRef]

Held, R.

J. Gwiazda, J. Bauer, F. Thorn, R. Held, “Development of spatial contrast sensitivity from infancy to adulthood: psychophysical data,” Optom. Vision Sci. 74, 785–789 (1997).
[CrossRef]

Herman, L.

L. Herman, M. F. Peacock, M. P. Yunker, C. J. Madsen, “Bottlenose dolphin: double-slit pupil yields equivalent aerial and underwater diurnal activity,” Science 189, 650–652 (1975).
[CrossRef] [PubMed]

Kröger, R. H. H.

A. Gislén, M. Dacke, R. H. H. Kröger, M. Abrahamson, D.-E. Nilsson, E. J. Warrant, “Superior underwater vision in a human population of sea-gypsies,” Curr. Biol. 13, 833–836 (2003).
[CrossRef]

A. Gislén, E. J. Warrant, R. H. H. Kröger, “Voluntary accommodation improves underwater vision in humans,” manuscript available from the authors (anna.gislen@cob.lu.se).

Madsen, C. J.

L. Herman, M. F. Peacock, M. P. Yunker, C. J. Madsen, “Bottlenose dolphin: double-slit pupil yields equivalent aerial and underwater diurnal activity,” Science 189, 650–652 (1975).
[CrossRef] [PubMed]

Marg, E.

E. Marg, M. W. Morgan, “The pupillary near reflex,” Am. J. Optom. Arch. Am. Acad. Optom. 26, 183–198 (1949).
[CrossRef] [PubMed]

Morgan, M. W.

E. Marg, M. W. Morgan, “The pupillary near reflex,” Am. J. Optom. Arch. Am. Acad. Optom. 26, 183–198 (1949).
[CrossRef] [PubMed]

Nilsson, D.-E.

A. Gislén, M. Dacke, R. H. H. Kröger, M. Abrahamson, D.-E. Nilsson, E. J. Warrant, “Superior underwater vision in a human population of sea-gypsies,” Curr. Biol. 13, 833–836 (2003).
[CrossRef]

Olzak, L. A.

L. A. Olzak, J. P. Thomas, “Seeing spatial patterns,” in Handbook of Perception and Human Performance, K. R. Boff, L. Kaufman, J. P. Thomas, eds. (Wiley, New York, 1986), Chap. 7.

Peacock, M. F.

L. Herman, M. F. Peacock, M. P. Yunker, C. J. Madsen, “Bottlenose dolphin: double-slit pupil yields equivalent aerial and underwater diurnal activity,” Science 189, 650–652 (1975).
[CrossRef] [PubMed]

Rivamonte, L. A.

L. A. Rivamonte, “Eye model to account for comparable aerial and underwater acuities of the bottlenose dolphin,” Neth. J. Sea Res. 10, 491–498 (1976).
[CrossRef]

Robson, J. G.

F. W. Campbell, J. G. Robson, “The application of Fourier analysis to the visibility of gratings,” J. Physiol. (London) 197, 551–566 (1968).

Roling, P.

P. T. Sowden, I. R. L. Davies, P. Roling, “Perceptual learning of the detection of features in X-ray images: a functional role for improvement in adults’ visual sensitivity?” J. Exp. Psychol. Hum. Percept. Perform. 26, 379–390 (2000).
[CrossRef] [PubMed]

Rose, D.

P. T. Sowden, D. Rose, I. R. L. Davies, “Perceptual learning of luminance contrast detection: specific for spatial frequency and retinal location but not orientation,” Vision Res. 42, 1249–1258 (2002).
[CrossRef] [PubMed]

Roth, N.

N. Roth, “Effect of reduced retinal illuminance on the pupillary near reflex,” Vision Res. 9, 1259–1266 (1969).
[CrossRef] [PubMed]

Schaeffel, F.

F. Schaeffel, H. Wilhelm, E. Zrenner, “Inter-individual variability in the dynamics of natural accommodation in humans: relation to age and refractive errors,” J. Physiol. (London) 461, 301–320 (1993).

F. Schaeffel, “Underwater vision in semi-aquatic European snakes,” Naturwissenschaften 78, 373–375 (1991).
[CrossRef]

F. Schaeffel, A. De Queiroz, “Alternative mechanisms of enhanced underwater vision in the Garter snakes Thamnopsis melanogaster and T. couchii,” Copeia 1, 50–58 (1990).
[CrossRef]

Schwartz, F.

F. Thorn, F. Schwartz, “Effects of dioptric blur on Snellen and grating acuity,” Optom. Vision Sci. 67, 3–7 (1990).
[CrossRef]

Sivak, J. G.

J. G. Sivak, “A survey of vertebrate strategies for vision in air and water,” in Sensory Ecology, M. A. Ali, ed. (Plenum, New York, 1978), pp. 503–519.

Smith, W. J.

W. J. Smith, Modern Optical Engineering (McGraw-Hill, New York, 1966).

Sowden, P. T.

P. T. Sowden, D. Rose, I. R. L. Davies, “Perceptual learning of luminance contrast detection: specific for spatial frequency and retinal location but not orientation,” Vision Res. 42, 1249–1258 (2002).
[CrossRef] [PubMed]

P. T. Sowden, I. R. L. Davies, P. Roling, “Perceptual learning of the detection of features in X-ray images: a functional role for improvement in adults’ visual sensitivity?” J. Exp. Psychol. Hum. Percept. Perform. 26, 379–390 (2000).
[CrossRef] [PubMed]

Strang, N. C.

R. L. Woods, N. C. Strang, D. A. Atchison, “Measuring contrast sensitivity with inappropriate optical correction,” Ophthalmic Physiol. Opt. 20, 442–451 (2000).
[PubMed]

N. C. Strang, D. A. Atchinson, R. L. Woods, “Effects of defocus and pupil size on human contrast sensitivity,” Ophthalmic Physiol. Opt. 19, 415–426 (1999).
[CrossRef]

Thomas, J. P.

L. A. Olzak, J. P. Thomas, “Seeing spatial patterns,” in Handbook of Perception and Human Performance, K. R. Boff, L. Kaufman, J. P. Thomas, eds. (Wiley, New York, 1986), Chap. 7.

Thorn, F.

J. Gwiazda, J. Bauer, F. Thorn, R. Held, “Development of spatial contrast sensitivity from infancy to adulthood: psychophysical data,” Optom. Vision Sci. 74, 785–789 (1997).
[CrossRef]

F. Thorn, F. Schwartz, “Effects of dioptric blur on Snellen and grating acuity,” Optom. Vision Sci. 67, 3–7 (1990).
[CrossRef]

Warrant, E. J.

A. Gislén, M. Dacke, R. H. H. Kröger, M. Abrahamson, D.-E. Nilsson, E. J. Warrant, “Superior underwater vision in a human population of sea-gypsies,” Curr. Biol. 13, 833–836 (2003).
[CrossRef]

A. Gislén, E. J. Warrant, R. H. H. Kröger, “Voluntary accommodation improves underwater vision in humans,” manuscript available from the authors (anna.gislen@cob.lu.se).

Wilhelm, H.

F. Schaeffel, H. Wilhelm, E. Zrenner, “Inter-individual variability in the dynamics of natural accommodation in humans: relation to age and refractive errors,” J. Physiol. (London) 461, 301–320 (1993).

Woods, R. L.

R. L. Woods, N. C. Strang, D. A. Atchison, “Measuring contrast sensitivity with inappropriate optical correction,” Ophthalmic Physiol. Opt. 20, 442–451 (2000).
[PubMed]

N. C. Strang, D. A. Atchinson, R. L. Woods, “Effects of defocus and pupil size on human contrast sensitivity,” Ophthalmic Physiol. Opt. 19, 415–426 (1999).
[CrossRef]

Yunker, M. P.

L. Herman, M. F. Peacock, M. P. Yunker, C. J. Madsen, “Bottlenose dolphin: double-slit pupil yields equivalent aerial and underwater diurnal activity,” Science 189, 650–652 (1975).
[CrossRef] [PubMed]

Zrenner, E.

F. Schaeffel, H. Wilhelm, E. Zrenner, “Inter-individual variability in the dynamics of natural accommodation in humans: relation to age and refractive errors,” J. Physiol. (London) 461, 301–320 (1993).

Am. J. Optom. Arch. Am. Acad. Optom. (1)

E. Marg, M. W. Morgan, “The pupillary near reflex,” Am. J. Optom. Arch. Am. Acad. Optom. 26, 183–198 (1949).
[CrossRef] [PubMed]

Copeia (1)

F. Schaeffel, A. De Queiroz, “Alternative mechanisms of enhanced underwater vision in the Garter snakes Thamnopsis melanogaster and T. couchii,” Copeia 1, 50–58 (1990).
[CrossRef]

Curr. Biol. (1)

A. Gislén, M. Dacke, R. H. H. Kröger, M. Abrahamson, D.-E. Nilsson, E. J. Warrant, “Superior underwater vision in a human population of sea-gypsies,” Curr. Biol. 13, 833–836 (2003).
[CrossRef]

J. Exp. Psychol. Hum. Percept. Perform. (1)

P. T. Sowden, I. R. L. Davies, P. Roling, “Perceptual learning of the detection of features in X-ray images: a functional role for improvement in adults’ visual sensitivity?” J. Exp. Psychol. Hum. Percept. Perform. 26, 379–390 (2000).
[CrossRef] [PubMed]

J. Physiol. (London) (2)

F. Schaeffel, H. Wilhelm, E. Zrenner, “Inter-individual variability in the dynamics of natural accommodation in humans: relation to age and refractive errors,” J. Physiol. (London) 461, 301–320 (1993).

F. W. Campbell, J. G. Robson, “The application of Fourier analysis to the visibility of gratings,” J. Physiol. (London) 197, 551–566 (1968).

Naturwissenschaften (1)

F. Schaeffel, “Underwater vision in semi-aquatic European snakes,” Naturwissenschaften 78, 373–375 (1991).
[CrossRef]

Neth. J. Sea Res. (1)

L. A. Rivamonte, “Eye model to account for comparable aerial and underwater acuities of the bottlenose dolphin,” Neth. J. Sea Res. 10, 491–498 (1976).
[CrossRef]

Ophthalmic Physiol. Opt. (2)

N. C. Strang, D. A. Atchinson, R. L. Woods, “Effects of defocus and pupil size on human contrast sensitivity,” Ophthalmic Physiol. Opt. 19, 415–426 (1999).
[CrossRef]

R. L. Woods, N. C. Strang, D. A. Atchison, “Measuring contrast sensitivity with inappropriate optical correction,” Ophthalmic Physiol. Opt. 20, 442–451 (2000).
[PubMed]

Optom. Vision Sci. (2)

J. Gwiazda, J. Bauer, F. Thorn, R. Held, “Development of spatial contrast sensitivity from infancy to adulthood: psychophysical data,” Optom. Vision Sci. 74, 785–789 (1997).
[CrossRef]

F. Thorn, F. Schwartz, “Effects of dioptric blur on Snellen and grating acuity,” Optom. Vision Sci. 67, 3–7 (1990).
[CrossRef]

Science (1)

L. Herman, M. F. Peacock, M. P. Yunker, C. J. Madsen, “Bottlenose dolphin: double-slit pupil yields equivalent aerial and underwater diurnal activity,” Science 189, 650–652 (1975).
[CrossRef] [PubMed]

Vision Res. (4)

K. K. De Valois, “Spatial frequency adaptation can enhance contrast sensitivity,” Vision Res. 17, 1057–1065 (1977).
[CrossRef] [PubMed]

A. Bradley, R. D. Freeman, “Contrast sensitivity in children,” Vision Res. 22, 953–959 (1982).
[CrossRef] [PubMed]

N. Roth, “Effect of reduced retinal illuminance on the pupillary near reflex,” Vision Res. 9, 1259–1266 (1969).
[CrossRef] [PubMed]

P. T. Sowden, D. Rose, I. R. L. Davies, “Perceptual learning of luminance contrast detection: specific for spatial frequency and retinal location but not orientation,” Vision Res. 42, 1249–1258 (2002).
[CrossRef] [PubMed]

Other (6)

A. Gislén, M. Dacke, “A simple way to assess contrast sensitivity in children living in remote areas,” manuscript available from the authors (anna.gislen@cob.lu.se).

H. Davson, Physiology of the Eye, 5th ed. (MacMillan, London, 1990), p. 830.

J. G. Sivak, “A survey of vertebrate strategies for vision in air and water,” in Sensory Ecology, M. A. Ali, ed. (Plenum, New York, 1978), pp. 503–519.

L. A. Olzak, J. P. Thomas, “Seeing spatial patterns,” in Handbook of Perception and Human Performance, K. R. Boff, L. Kaufman, J. P. Thomas, eds. (Wiley, New York, 1986), Chap. 7.

W. J. Smith, Modern Optical Engineering (McGraw-Hill, New York, 1966).

A. Gislén, E. J. Warrant, R. H. H. Kröger, “Voluntary accommodation improves underwater vision in humans,” manuscript available from the authors (anna.gislen@cob.lu.se).

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (2)

Fig. 1
Fig. 1

Necessary contrast sensitivity as a function of spatial frequency, with a set pupil diameter of 2.50 mm and a defocus of 43 D. Notice how the minimum values of contrast sensitivity required to detect a spatial pattern increase only slowly.

Fig. 2
Fig. 2

Necessary contrast sensitivity as a function of spatial frequency for Moken children in an underwater environment. Accommodation of 16 D results in a defocus of 27 D; measured pupil size was 1.96 mm. This curve should be compared with that in Fig. 1, which corresponds to the pupil size and defocus of the untrained European children underwater.

Tables (2)

Tables Icon

Table 1 Contrast Sensitivity as a Function of z for the First 24 Values Only

Tables Icon

Table 2 Values Used to Calculate Required Contrast Sensitivity a

Equations (4)

Equations on this page are rendered with MathJax. Learn more.

S=2J1(z)z,
z=πBfS,
z=0.180faPΔD,
C=-log(|S|)

Metrics