Abstract

Reflectance spectra from discrete sites in the human ocular fundus were measured with an experimental reflectometer in the visible and near-infrared parts of the spectrum. The principal study population consisted of ten subjects 22 to 38 years of age withba wide range of degree of fundus melanin pigmentation. Reflectance spectra were obtained from the nasal fundus, the fovea, and an area 2.5° from the fovea. Spectra were also recorded from several older subjects and from one aphakic patient with a coloboma. The reflectance spectra were found to be influenced by the degree of individual and local melanin pigmentation of the fundus, the amount of blood in the choroid, the transmission properties of the ocular media, and the discrete reflections in the stratified fundus layers. Mathematical models of the optical properties of the stratified layers are proposed and are fitted to the experimental fundus reflectance spectra. The models account for the absorption by blood, melanin, macular pigment, and ocular media, and incorporate tissue scattering and discrete reflectors corresponding to anatomical layers.

© 1989 Optical Society of America

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    [CrossRef]
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    [PubMed]
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    [CrossRef] [PubMed]
  4. M. Millodot, “Reflection from the Fundus of the Eye and Its Relevance to Retinoscopy,” Atti Fond. Giorgio Ronchi 27, 31 (1972).
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    [CrossRef] [PubMed]
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    [PubMed]
  7. D. O’Leary, M. Millodot, “The Discrepancy Between Retinoscopic and Subjective Refraction: Effect of Light Polarization,” Am. J. Optom. Physiol. Opt. 55, 553 (1978).
    [CrossRef]
  8. W. N. Charman, “Reflection of Plane-Polarized Light by the Retina,” Br. J. Physiol. Opt. 34, 34 (1980).
    [PubMed]
  9. J.-M. Gorrand, R. Alfieri, J.-Y. Boire, “Diffusion of the Retinal Layers of the Living Human Eye,” Vision Res. 24, 1097 (1984).
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  12. D. J. Faulkner, C. M. Kemp, “Human Rhodopsin Measurement Using a T.V.-Based Imaging Fundus Reflectometer,” Vision Res. 24, 221 (1984).
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  24. F. C. Delori, E. S. Gragoudas, R. Francisco, R. C. Pruett, “Monochromatic Ophthalmoscopy and Fundus Photography,” Arch. Ophthalmol. 95, 861 (1977).
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  28. F. C. Delori, K. P. Plibsen, “Reflectance Properties of the Optic Disc,” Noninvasive Assessment of the Visual System. OSA Technical Digest, in press.
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  30. Determination of pigment concentrations requires a tight fit both in red light (melanin) and in green light (hemoglobin). Because of the large differences in reflectance in those two spectral bands (Fig. 2), such fit could be achieved by minimizing the relative errors or by using a weight Wλ=Robs, λ−2 in Eq. (2). However, a lesser weight might be desired for short wavelengths to minimize the effect of inaccuracies caused by ocular media light scattering, low signal-to-noise ratio, etc. We therefore selected Wλ=Robs,λ−1 as a compromise.
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  34. I. A. Menon, S. Persad, H. F. Haberman, C. J. Kurian, P. K. Basu, “A Qualitative Study of the Melanins from Blue and Brown Human Eyes,” Exp. Eye Res. 34, 531 (1982).
    [CrossRef] [PubMed]
  35. W. J. Geeraets, R. C. Williams, G. Chan, W. T. Ham, D. Guerry, F. H. Schmidt, “The Relative Absorption of Thermal Energy in Retina and Choroid,” Invest. Ophthalmol. 1, 340 (1962).
    [PubMed]
  36. J. J. Weiter, F. C. Delori, G. L. Wing, K. A. Fitch, “Retinal Pigment Epithelium Lipofuscin and Melanin and Choroidal Melanin in Human Eyes,” Invest. Ophthalmol. Vis. Sci. 27, 145 (1986).
    [PubMed]
  37. The in vitro measurements of Weiter et al.36 were made with polychromatic light in the 500–600-nm spectral range. Using the melanin absorption spectrum of Fig. 4 (solid curve), we calculated that the absorption coefficient at 500 nm should be about 1.6 times higher than those reported in Weiter’s study.
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  42. M. J. Hogan, J. A. Alvarado, J. E. Weddell, Histology of the Human Eye (Saunders, Philadelphia, 1971).
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    [CrossRef] [PubMed]
  44. D. M. Snodderly, P. K. Brown, F. C. Delori, J. D. Auran, “The Macular Pigment. I. Absorbance Spectra, Localization, and Discrimination from Other Yellow Pigments in Primate Retinas,” Invest. Ophthalmol. Vis. Sci. 25, 660 (1984).
    [PubMed]
  45. E. A. Boetner, J. R. Wolter, “Transmission of the Ocular Media,” Invest. Ophthalmol. 1, 776 (1962).
  46. J. Walraven, “Spatial Characteristics of Chromatic Induction: the Segregation of Lateral Effects from Straylight Artefacts,” Vision Res. 13, 1739 (1973).
    [CrossRef] [PubMed]
  47. R. S. Smith, M. N. Stein, “Ocular Hazards of Transscleral Laser Radiation. I. Spectral Reflection and Transmission of the Sclera, Choroid and Retina,” Am. J. Ophthalmol. 66, 21 (1968).
    [PubMed]
  48. M. Alpern, S. Thompson, M. S. Lee, “Spectral Transmittance of Visible Light by the Living Human Eye,” J. Opt. Soc. Am. 55, 723 (1965).
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  49. M. T. Mori, R. C. Zeimer, M. F. Goldberg, “Noninvasive Measurement of Retinal Thickness: a Potential Diagnostic Tool for Macular Edema and Atrophy,” Invest. Ophthalmol. Vis. Sci. 29 (ARVO Suppl), 339 (1988).
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  51. G. Kortum, Reflectance Spectroscopy (Springer-Verlag, New York, 1969), p. 116.
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    [CrossRef]
  53. R. R. Anderson, J. A. Parrish, “The Optics of Human Skin,” J. Invest. Dermatol. 77, 13 (1981).
    [CrossRef] [PubMed]
  54. S. Takatani, M. D. Graham, “Theoretical Analysis of Diffuse Reflectance from a Two-Layer Tissue Model,” IEEE Trans. Biomed. Eng. BME-26, 656 (1979).
    [CrossRef]
  55. R. A. Bone, J. M. B. Sparrock, “Comparison of Macular Pigment Densities in Human Eyes,” Vision Res. 11, 1057 (1971).
    [CrossRef] [PubMed]
  56. D. W. Lubbers, R. Wodick, “Absolute Reflection Photometry Applied to the Measurement of Capillary Oxyhaemoglobin Saturation of the Skin in Man,” Oxygen Meas. Biol. Med. 1, 85 (1974).
  57. L. N. M. Duysens, “The Flattening of the Absorption Spectrum of Suspensions, as Compared to that of Solutions,” Biochim. Biophys. Acta 19, 1 (1956).
    [CrossRef] [PubMed]

1989 (1)

1988 (2)

F. Delori, “Noninvasive Technique for Oximetry of Blood in Retinal Vessels,” Appl. Opt. 27, 1113 (1988).
[CrossRef] [PubMed]

M. T. Mori, R. C. Zeimer, M. F. Goldberg, “Noninvasive Measurement of Retinal Thickness: a Potential Diagnostic Tool for Macular Edema and Atrophy,” Invest. Ophthalmol. Vis. Sci. 29 (ARVO Suppl), 339 (1988).

1987 (1)

K. R. Alexander, P. E. Kilbride, G. A. Fishman, M. Fishman, “Macular Pigment and Reduced Foveal Short-Wavelength Sensitivity in Retinitis Pigmentosa,” Vision Res. 27, 1077 (1987).
[CrossRef] [PubMed]

1986 (2)

J. J. Weiter, F. C. Delori, G. L. Wing, K. A. Fitch, “Retinal Pigment Epithelium Lipofuscin and Melanin and Choroidal Melanin in Human Eyes,” Invest. Ophthalmol. Vis. Sci. 27, 145 (1986).
[PubMed]

D. van Norren, L. F. Tiemeijer, “Spectral Reflectance of the Human Eye,” Vision Res. 26, 313 (1986).
[CrossRef] [PubMed]

1984 (4)

D. J. Faulkner, C. M. Kemp, “Human Rhodopsin Measurement Using a T.V.-Based Imaging Fundus Reflectometer,” Vision Res. 24, 221 (1984).
[CrossRef] [PubMed]

J.-M. Gorrand, R. Alfieri, J.-Y. Boire, “Diffusion of the Retinal Layers of the Living Human Eye,” Vision Res. 24, 1097 (1984).
[CrossRef] [PubMed]

S. Tane, J. Kohno, J. Horikoshi, K. Kondo, K. Ohashi, A. Komatsu, T. Kakehashi, “The Study on the Microscopic Biometry of the Thickness of the Human Retina, Choroid and Sclera by Ultrasound,” Acta Soc. Ophthalmol. Jpn. 88, 1412 (1984).

D. M. Snodderly, P. K. Brown, F. C. Delori, J. D. Auran, “The Macular Pigment. I. Absorbance Spectra, Localization, and Discrimination from Other Yellow Pigments in Primate Retinas,” Invest. Ophthalmol. Vis. Sci. 25, 660 (1984).
[PubMed]

1983 (3)

A. Bill, G. Sperber, K. Ujiie, “Physiology of the Choroidal Vascular Bed,” Int. Ophthalmol. 6, 101 (1983).
[CrossRef] [PubMed]

J. Gloster, “Fundus Reflectometry in the Study of the Choroidal Circulation,” Int. Ophthalmol. 6, 109 (1983).
[CrossRef] [PubMed]

P. E. Kilbride, J. S. Read, G. A. Fishman, M. Fishman, “Determination of Human Cone Pigment Density Difference Spectra in Spatially Resolved Regions of the Fovea,” Vision Res. 12, 1341 (1983).
[CrossRef]

1982 (1)

I. A. Menon, S. Persad, H. F. Haberman, C. J. Kurian, P. K. Basu, “A Qualitative Study of the Melanins from Blue and Brown Human Eyes,” Exp. Eye Res. 34, 531 (1982).
[CrossRef] [PubMed]

1981 (2)

D. van Norren, J. van der Kraats, “A Continuously Recording Retinal Densitometer,” Vision Res. 21, 897 (1981).
[CrossRef] [PubMed]

R. R. Anderson, J. A. Parrish, “The Optics of Human Skin,” J. Invest. Dermatol. 77, 13 (1981).
[CrossRef] [PubMed]

1980 (2)

W. N. Charman, “Reflection of Plane-Polarized Light by the Retina,” Br. J. Physiol. Opt. 34, 34 (1980).
[PubMed]

F. Delori, J. S. Parker, M. A. Mainster, “Light Levels in Fundus Photography and Fluorescein Angiography,” Vision Res. 20, 1099 (1980).
[CrossRef] [PubMed]

1979 (2)

D. J. Coleman, F. L. Lizzi, “In vivo Choroidal Thickness Measurement,” Am. J. Ophthalmol. 88, 369 (1979).
[PubMed]

S. Takatani, M. D. Graham, “Theoretical Analysis of Diffuse Reflectance from a Two-Layer Tissue Model,” IEEE Trans. Biomed. Eng. BME-26, 656 (1979).
[CrossRef]

1978 (1)

D. O’Leary, M. Millodot, “The Discrepancy Between Retinoscopic and Subjective Refraction: Effect of Light Polarization,” Am. J. Optom. Physiol. Opt. 55, 553 (1978).
[CrossRef]

1977 (2)

R. W. Flower, D. S. McLeod, S. M. Pitts, “Reflection of Light by Small Areas of the Ocular Fundus,” Invest. Ophthalmol. Vis. Sci. 16, 981 (1977).
[PubMed]

F. C. Delori, E. S. Gragoudas, R. Francisco, R. C. Pruett, “Monochromatic Ophthalmoscopy and Fundus Photography,” Arch. Ophthalmol. 95, 861 (1977).
[CrossRef] [PubMed]

1976 (1)

W. N. Charman, J. A. M. Jennings, “Objective Measurements of the Longitudinal Chromatic Aberration of the Human Eye,” Vision Res. 16, 999 (1976).
[CrossRef] [PubMed]

1974 (4)

N. H. Bakker, “Fundus Reflectometry, an Experimental Study,” Doc. Ophthalmol. 38, 271 (1974).
[PubMed]

D. van Norren, J. J. Vos, “Spectral Transmission of the Human Ocular Media,” Vision Res. 14, 1237 (1974).
[CrossRef]

W. Hunold, P. Malessa, “Spectrophotometric Determination of Melanin Pigmentation of the Human Ocular Fundus in vivo,” Ophthalmic Res. 6, 355 (1974).
[CrossRef]

D. W. Lubbers, R. Wodick, “Absolute Reflection Photometry Applied to the Measurement of Capillary Oxyhaemoglobin Saturation of the Skin in Man,” Oxygen Meas. Biol. Med. 1, 85 (1974).

1973 (1)

J. Walraven, “Spatial Characteristics of Chromatic Induction: the Segregation of Lateral Effects from Straylight Artefacts,” Vision Res. 13, 1739 (1973).
[CrossRef] [PubMed]

1972 (1)

M. Millodot, “Reflection from the Fundus of the Eye and Its Relevance to Retinoscopy,” Atti Fond. Giorgio Ronchi 27, 31 (1972).

1971 (1)

R. A. Bone, J. M. B. Sparrock, “Comparison of Macular Pigment Densities in Human Eyes,” Vision Res. 11, 1057 (1971).
[CrossRef] [PubMed]

1969 (1)

R. Rohler, U. Miller, M. Aberl, “Zur Messung der Modulationsiibertragungsfunktion des Lebenden Menschlichen Auges im Reflektierten Licht,” Vision Res. 9, 407 (1969).
[CrossRef] [PubMed]

1968 (3)

W. A. Rushton, G. H. Henri, “Bleaching and Regeneration of Cone Pigments in Man,” Vision Res. 8, 617 (1968).
[CrossRef] [PubMed]

R. S. Smith, M. N. Stein, “Ocular Hazards of Transscleral Laser Radiation. I. Spectral Reflection and Transmission of the Sclera, Choroid and Retina,” Am. J. Ophthalmol. 66, 21 (1968).
[PubMed]

R. L. Longini, R. Zdrojkowski, “A Note on the Theory of Backscattering of Light by Living Tissue,” IEEE Trans. Biomed. Eng. BME-15, 4 (1968).
[CrossRef]

1967 (1)

J. Gloster, “Fundus Oximetry,” Exp. Eye Res. 6, 187 (1967).
[CrossRef] [PubMed]

1966 (2)

R. A. Weale, “Polarized Light and the Human Fundus Oculi,” J. Physiol. 186, 175 (1966).
[PubMed]

T. Behrendt, T. D. Duane, “Investigation of Fundus Oculi with Spectral Reflectance Photography. I: Depth and Integrity of Fundal Structures,” Arch. Ophthalmol. 75, 375 (1966).
[CrossRef] [PubMed]

1965 (3)

1962 (2)

W. J. Geeraets, R. C. Williams, G. Chan, W. T. Ham, D. Guerry, F. H. Schmidt, “The Relative Absorption of Thermal Energy in Retina and Choroid,” Invest. Ophthalmol. 1, 340 (1962).
[PubMed]

E. A. Boetner, J. R. Wolter, “Transmission of the Ocular Media,” Invest. Ophthalmol. 1, 776 (1962).

1956 (1)

L. N. M. Duysens, “The Flattening of the Absorption Spectrum of Suspensions, as Compared to that of Solutions,” Biochim. Biophys. Acta 19, 1 (1956).
[CrossRef] [PubMed]

1952 (1)

G. S. Brindley, E. N. Willmer, “The Reflection of Light from the Macular and Peripheral Fundus Oculi in Man,” J. Physiol. (London) 116, 350 (1952).

Aberl, M.

R. Rohler, U. Miller, M. Aberl, “Zur Messung der Modulationsiibertragungsfunktion des Lebenden Menschlichen Auges im Reflektierten Licht,” Vision Res. 9, 407 (1969).
[CrossRef] [PubMed]

Alexander, K. R.

K. R. Alexander, P. E. Kilbride, G. A. Fishman, M. Fishman, “Macular Pigment and Reduced Foveal Short-Wavelength Sensitivity in Retinitis Pigmentosa,” Vision Res. 27, 1077 (1987).
[CrossRef] [PubMed]

Alfieri, R.

J.-M. Gorrand, R. Alfieri, J.-Y. Boire, “Diffusion of the Retinal Layers of the Living Human Eye,” Vision Res. 24, 1097 (1984).
[CrossRef] [PubMed]

Alpern, M.

Alvarado, J. A.

M. J. Hogan, J. A. Alvarado, J. E. Weddell, Histology of the Human Eye (Saunders, Philadelphia, 1971).

Anderson, R. R.

R. R. Anderson, J. A. Parrish, “The Optics of Human Skin,” J. Invest. Dermatol. 77, 13 (1981).
[CrossRef] [PubMed]

Auran, J. D.

D. M. Snodderly, P. K. Brown, F. C. Delori, J. D. Auran, “The Macular Pigment. I. Absorbance Spectra, Localization, and Discrimination from Other Yellow Pigments in Primate Retinas,” Invest. Ophthalmol. Vis. Sci. 25, 660 (1984).
[PubMed]

Bakker, N. H.

N. H. Bakker, “Fundus Reflectometry, an Experimental Study,” Doc. Ophthalmol. 38, 271 (1974).
[PubMed]

Basu, P. K.

I. A. Menon, S. Persad, H. F. Haberman, C. J. Kurian, P. K. Basu, “A Qualitative Study of the Melanins from Blue and Brown Human Eyes,” Exp. Eye Res. 34, 531 (1982).
[CrossRef] [PubMed]

Behrendt, T.

T. Behrendt, T. D. Duane, “Investigation of Fundus Oculi with Spectral Reflectance Photography. I: Depth and Integrity of Fundal Structures,” Arch. Ophthalmol. 75, 375 (1966).
[CrossRef] [PubMed]

Bevington, P. R.

P. R. Bevington, Data Reduction and Error Analysis for the Physical Sciences (McGraw-Hill, New York, 1969), p. 235.

Bill, A.

A. Bill, G. Sperber, K. Ujiie, “Physiology of the Choroidal Vascular Bed,” Int. Ophthalmol. 6, 101 (1983).
[CrossRef] [PubMed]

Birngruber, R.

V. P. Gabel, R. Birngruber, F. Hillekamp, “Visible and Near Infrared Light Absorption in Pigment Epithelium and Choroid,” in Twenty-Third Concilium Ophthalmologicum, Kyoto, K. Shimizu, Ed. (Excerpta Medica, Amsterdam, 1978).

Boetner, E. A.

E. A. Boetner, J. R. Wolter, “Transmission of the Ocular Media,” Invest. Ophthalmol. 1, 776 (1962).

Boire, J.-Y.

J.-M. Gorrand, R. Alfieri, J.-Y. Boire, “Diffusion of the Retinal Layers of the Living Human Eye,” Vision Res. 24, 1097 (1984).
[CrossRef] [PubMed]

Bone, R. A.

R. A. Bone, J. M. B. Sparrock, “Comparison of Macular Pigment Densities in Human Eyes,” Vision Res. 11, 1057 (1971).
[CrossRef] [PubMed]

Boogaard, J.

Brindley, G. S.

G. S. Brindley, E. N. Willmer, “The Reflection of Light from the Macular and Peripheral Fundus Oculi in Man,” J. Physiol. (London) 116, 350 (1952).

Brown, P. K.

D. M. Snodderly, P. K. Brown, F. C. Delori, J. D. Auran, “The Macular Pigment. I. Absorbance Spectra, Localization, and Discrimination from Other Yellow Pigments in Primate Retinas,” Invest. Ophthalmol. Vis. Sci. 25, 660 (1984).
[PubMed]

Chan, G.

W. J. Geeraets, R. C. Williams, G. Chan, W. T. Ham, D. Guerry, F. H. Schmidt, “The Relative Absorption of Thermal Energy in Retina and Choroid,” Invest. Ophthalmol. 1, 340 (1962).
[PubMed]

Charman, W. N.

W. N. Charman, “Reflection of Plane-Polarized Light by the Retina,” Br. J. Physiol. Opt. 34, 34 (1980).
[PubMed]

W. N. Charman, J. A. M. Jennings, “Objective Measurements of the Longitudinal Chromatic Aberration of the Human Eye,” Vision Res. 16, 999 (1976).
[CrossRef] [PubMed]

Coleman, D. J.

D. J. Coleman, F. L. Lizzi, “In vivo Choroidal Thickness Measurement,” Am. J. Ophthalmol. 88, 369 (1979).
[PubMed]

Delori, F.

F. Delori, “Noninvasive Technique for Oximetry of Blood in Retinal Vessels,” Appl. Opt. 27, 1113 (1988).
[CrossRef] [PubMed]

F. Delori, J. S. Parker, M. A. Mainster, “Light Levels in Fundus Photography and Fluorescein Angiography,” Vision Res. 20, 1099 (1980).
[CrossRef] [PubMed]

Delori, F. C.

K. P. Pflibsen, F. C. Delori, O. Pomerantzeff, M. M. Pankratov, “Fundus Reflectometry for Photocoagulation Dosimetry,” Appl. Opt. 28, 1084 (1989).
[CrossRef] [PubMed]

J. J. Weiter, F. C. Delori, G. L. Wing, K. A. Fitch, “Retinal Pigment Epithelium Lipofuscin and Melanin and Choroidal Melanin in Human Eyes,” Invest. Ophthalmol. Vis. Sci. 27, 145 (1986).
[PubMed]

D. M. Snodderly, P. K. Brown, F. C. Delori, J. D. Auran, “The Macular Pigment. I. Absorbance Spectra, Localization, and Discrimination from Other Yellow Pigments in Primate Retinas,” Invest. Ophthalmol. Vis. Sci. 25, 660 (1984).
[PubMed]

F. C. Delori, E. S. Gragoudas, R. Francisco, R. C. Pruett, “Monochromatic Ophthalmoscopy and Fundus Photography,” Arch. Ophthalmol. 95, 861 (1977).
[CrossRef] [PubMed]

F. C. Delori, K. P. Plibsen, “Reflectance Properties of the Optic Disc,” Noninvasive Assessment of the Visual System. OSA Technical Digest, in press.

Duane, T. D.

T. Behrendt, T. D. Duane, “Investigation of Fundus Oculi with Spectral Reflectance Photography. I: Depth and Integrity of Fundal Structures,” Arch. Ophthalmol. 75, 375 (1966).
[CrossRef] [PubMed]

Duysens, L. N. M.

L. N. M. Duysens, “The Flattening of the Absorption Spectrum of Suspensions, as Compared to that of Solutions,” Biochim. Biophys. Acta 19, 1 (1956).
[CrossRef] [PubMed]

Faulkner, D. J.

D. J. Faulkner, C. M. Kemp, “Human Rhodopsin Measurement Using a T.V.-Based Imaging Fundus Reflectometer,” Vision Res. 24, 221 (1984).
[CrossRef] [PubMed]

Fishman, G. A.

K. R. Alexander, P. E. Kilbride, G. A. Fishman, M. Fishman, “Macular Pigment and Reduced Foveal Short-Wavelength Sensitivity in Retinitis Pigmentosa,” Vision Res. 27, 1077 (1987).
[CrossRef] [PubMed]

P. E. Kilbride, J. S. Read, G. A. Fishman, M. Fishman, “Determination of Human Cone Pigment Density Difference Spectra in Spatially Resolved Regions of the Fovea,” Vision Res. 12, 1341 (1983).
[CrossRef]

Fishman, M.

K. R. Alexander, P. E. Kilbride, G. A. Fishman, M. Fishman, “Macular Pigment and Reduced Foveal Short-Wavelength Sensitivity in Retinitis Pigmentosa,” Vision Res. 27, 1077 (1987).
[CrossRef] [PubMed]

P. E. Kilbride, J. S. Read, G. A. Fishman, M. Fishman, “Determination of Human Cone Pigment Density Difference Spectra in Spatially Resolved Regions of the Fovea,” Vision Res. 12, 1341 (1983).
[CrossRef]

Fitch, K. A.

J. J. Weiter, F. C. Delori, G. L. Wing, K. A. Fitch, “Retinal Pigment Epithelium Lipofuscin and Melanin and Choroidal Melanin in Human Eyes,” Invest. Ophthalmol. Vis. Sci. 27, 145 (1986).
[PubMed]

Flower, R. W.

R. W. Flower, D. S. McLeod, S. M. Pitts, “Reflection of Light by Small Areas of the Ocular Fundus,” Invest. Ophthalmol. Vis. Sci. 16, 981 (1977).
[PubMed]

Francisco, R.

F. C. Delori, E. S. Gragoudas, R. Francisco, R. C. Pruett, “Monochromatic Ophthalmoscopy and Fundus Photography,” Arch. Ophthalmol. 95, 861 (1977).
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V. P. Gabel, R. Birngruber, F. Hillekamp, “Visible and Near Infrared Light Absorption in Pigment Epithelium and Choroid,” in Twenty-Third Concilium Ophthalmologicum, Kyoto, K. Shimizu, Ed. (Excerpta Medica, Amsterdam, 1978).

Geeraets, W. J.

W. J. Geeraets, R. C. Williams, G. Chan, W. T. Ham, D. Guerry, F. H. Schmidt, “The Relative Absorption of Thermal Energy in Retina and Choroid,” Invest. Ophthalmol. 1, 340 (1962).
[PubMed]

Gloster, J.

J. Gloster, “Fundus Reflectometry in the Study of the Choroidal Circulation,” Int. Ophthalmol. 6, 109 (1983).
[CrossRef] [PubMed]

J. Gloster, “Fundus Oximetry,” Exp. Eye Res. 6, 187 (1967).
[CrossRef] [PubMed]

Goldberg, M. F.

M. T. Mori, R. C. Zeimer, M. F. Goldberg, “Noninvasive Measurement of Retinal Thickness: a Potential Diagnostic Tool for Macular Edema and Atrophy,” Invest. Ophthalmol. Vis. Sci. 29 (ARVO Suppl), 339 (1988).

Gorrand, J.-M.

J.-M. Gorrand, R. Alfieri, J.-Y. Boire, “Diffusion of the Retinal Layers of the Living Human Eye,” Vision Res. 24, 1097 (1984).
[CrossRef] [PubMed]

Gragoudas, E. S.

F. C. Delori, E. S. Gragoudas, R. Francisco, R. C. Pruett, “Monochromatic Ophthalmoscopy and Fundus Photography,” Arch. Ophthalmol. 95, 861 (1977).
[CrossRef] [PubMed]

Graham, M. D.

S. Takatani, M. D. Graham, “Theoretical Analysis of Diffuse Reflectance from a Two-Layer Tissue Model,” IEEE Trans. Biomed. Eng. BME-26, 656 (1979).
[CrossRef]

Guerry, D.

W. J. Geeraets, R. C. Williams, G. Chan, W. T. Ham, D. Guerry, F. H. Schmidt, “The Relative Absorption of Thermal Energy in Retina and Choroid,” Invest. Ophthalmol. 1, 340 (1962).
[PubMed]

Haberman, H. F.

I. A. Menon, S. Persad, H. F. Haberman, C. J. Kurian, P. K. Basu, “A Qualitative Study of the Melanins from Blue and Brown Human Eyes,” Exp. Eye Res. 34, 531 (1982).
[CrossRef] [PubMed]

Ham, W. T.

W. J. Geeraets, R. C. Williams, G. Chan, W. T. Ham, D. Guerry, F. H. Schmidt, “The Relative Absorption of Thermal Energy in Retina and Choroid,” Invest. Ophthalmol. 1, 340 (1962).
[PubMed]

Henri, G. H.

W. A. Rushton, G. H. Henri, “Bleaching and Regeneration of Cone Pigments in Man,” Vision Res. 8, 617 (1968).
[CrossRef] [PubMed]

Hillekamp, F.

V. P. Gabel, R. Birngruber, F. Hillekamp, “Visible and Near Infrared Light Absorption in Pigment Epithelium and Choroid,” in Twenty-Third Concilium Ophthalmologicum, Kyoto, K. Shimizu, Ed. (Excerpta Medica, Amsterdam, 1978).

Hogan, M. J.

M. J. Hogan, J. A. Alvarado, J. E. Weddell, Histology of the Human Eye (Saunders, Philadelphia, 1971).

Horikoshi, J.

S. Tane, J. Kohno, J. Horikoshi, K. Kondo, K. Ohashi, A. Komatsu, T. Kakehashi, “The Study on the Microscopic Biometry of the Thickness of the Human Retina, Choroid and Sclera by Ultrasound,” Acta Soc. Ophthalmol. Jpn. 88, 1412 (1984).

Hunold, W.

W. Hunold, P. Malessa, “Spectrophotometric Determination of Melanin Pigmentation of the Human Ocular Fundus in vivo,” Ophthalmic Res. 6, 355 (1974).
[CrossRef]

Illinois, U.

R. C. Zeimer, U. Illinois, Research Eye Institute; personal communication (June1988).

Jennings, J. A. M.

W. N. Charman, J. A. M. Jennings, “Objective Measurements of the Longitudinal Chromatic Aberration of the Human Eye,” Vision Res. 16, 999 (1976).
[CrossRef] [PubMed]

Kakehashi, T.

S. Tane, J. Kohno, J. Horikoshi, K. Kondo, K. Ohashi, A. Komatsu, T. Kakehashi, “The Study on the Microscopic Biometry of the Thickness of the Human Retina, Choroid and Sclera by Ultrasound,” Acta Soc. Ophthalmol. Jpn. 88, 1412 (1984).

Kemp, C. M.

D. J. Faulkner, C. M. Kemp, “Human Rhodopsin Measurement Using a T.V.-Based Imaging Fundus Reflectometer,” Vision Res. 24, 221 (1984).
[CrossRef] [PubMed]

Kilbride, P. E.

K. R. Alexander, P. E. Kilbride, G. A. Fishman, M. Fishman, “Macular Pigment and Reduced Foveal Short-Wavelength Sensitivity in Retinitis Pigmentosa,” Vision Res. 27, 1077 (1987).
[CrossRef] [PubMed]

P. E. Kilbride, J. S. Read, G. A. Fishman, M. Fishman, “Determination of Human Cone Pigment Density Difference Spectra in Spatially Resolved Regions of the Fovea,” Vision Res. 12, 1341 (1983).
[CrossRef]

Kohno, J.

S. Tane, J. Kohno, J. Horikoshi, K. Kondo, K. Ohashi, A. Komatsu, T. Kakehashi, “The Study on the Microscopic Biometry of the Thickness of the Human Retina, Choroid and Sclera by Ultrasound,” Acta Soc. Ophthalmol. Jpn. 88, 1412 (1984).

Komatsu, A.

S. Tane, J. Kohno, J. Horikoshi, K. Kondo, K. Ohashi, A. Komatsu, T. Kakehashi, “The Study on the Microscopic Biometry of the Thickness of the Human Retina, Choroid and Sclera by Ultrasound,” Acta Soc. Ophthalmol. Jpn. 88, 1412 (1984).

Kondo, K.

S. Tane, J. Kohno, J. Horikoshi, K. Kondo, K. Ohashi, A. Komatsu, T. Kakehashi, “The Study on the Microscopic Biometry of the Thickness of the Human Retina, Choroid and Sclera by Ultrasound,” Acta Soc. Ophthalmol. Jpn. 88, 1412 (1984).

Kortum, G.

G. Kortum, Reflectance Spectroscopy (Springer-Verlag, New York, 1969), p. 116.

Kurian, C. J.

I. A. Menon, S. Persad, H. F. Haberman, C. J. Kurian, P. K. Basu, “A Qualitative Study of the Melanins from Blue and Brown Human Eyes,” Exp. Eye Res. 34, 531 (1982).
[CrossRef] [PubMed]

Kutner, M. H.

J. Neter, W. Wasserman, M. H. Kutner, Applied Linear Statistical Models (Richard D. Irwin, Inc., Homewood, IL, 1985), p. 580.

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Lerche, W.

W. Lerche, “Die Kapillarisierung der Menschlichen Retina,” in Eye Structure, II Symposium, J. W. Rohen, Ed. (Schattauer-Verlag, Stuttgart, 1965).

Lizzi, F. L.

D. J. Coleman, F. L. Lizzi, “In vivo Choroidal Thickness Measurement,” Am. J. Ophthalmol. 88, 369 (1979).
[PubMed]

Longini, R. L.

R. L. Longini, R. Zdrojkowski, “A Note on the Theory of Backscattering of Light by Living Tissue,” IEEE Trans. Biomed. Eng. BME-15, 4 (1968).
[CrossRef]

Lubbers, D. W.

D. W. Lubbers, R. Wodick, “Absolute Reflection Photometry Applied to the Measurement of Capillary Oxyhaemoglobin Saturation of the Skin in Man,” Oxygen Meas. Biol. Med. 1, 85 (1974).

Mainster, M. A.

F. Delori, J. S. Parker, M. A. Mainster, “Light Levels in Fundus Photography and Fluorescein Angiography,” Vision Res. 20, 1099 (1980).
[CrossRef] [PubMed]

Malessa, P.

W. Hunold, P. Malessa, “Spectrophotometric Determination of Melanin Pigmentation of the Human Ocular Fundus in vivo,” Ophthalmic Res. 6, 355 (1974).
[CrossRef]

McLeod, D. S.

R. W. Flower, D. S. McLeod, S. M. Pitts, “Reflection of Light by Small Areas of the Ocular Fundus,” Invest. Ophthalmol. Vis. Sci. 16, 981 (1977).
[PubMed]

Menon, I. A.

I. A. Menon, S. Persad, H. F. Haberman, C. J. Kurian, P. K. Basu, “A Qualitative Study of the Melanins from Blue and Brown Human Eyes,” Exp. Eye Res. 34, 531 (1982).
[CrossRef] [PubMed]

Miller, U.

R. Rohler, U. Miller, M. Aberl, “Zur Messung der Modulationsiibertragungsfunktion des Lebenden Menschlichen Auges im Reflektierten Licht,” Vision Res. 9, 407 (1969).
[CrossRef] [PubMed]

Millodot, M.

D. O’Leary, M. Millodot, “The Discrepancy Between Retinoscopic and Subjective Refraction: Effect of Light Polarization,” Am. J. Optom. Physiol. Opt. 55, 553 (1978).
[CrossRef]

M. Millodot, “Reflection from the Fundus of the Eye and Its Relevance to Retinoscopy,” Atti Fond. Giorgio Ronchi 27, 31 (1972).

Mori, M. T.

M. T. Mori, R. C. Zeimer, M. F. Goldberg, “Noninvasive Measurement of Retinal Thickness: a Potential Diagnostic Tool for Macular Edema and Atrophy,” Invest. Ophthalmol. Vis. Sci. 29 (ARVO Suppl), 339 (1988).

Munnik, A. A.

Neter, J.

J. Neter, W. Wasserman, M. H. Kutner, Applied Linear Statistical Models (Richard D. Irwin, Inc., Homewood, IL, 1985), p. 580.

O’Leary, D.

D. O’Leary, M. Millodot, “The Discrepancy Between Retinoscopic and Subjective Refraction: Effect of Light Polarization,” Am. J. Optom. Physiol. Opt. 55, 553 (1978).
[CrossRef]

Ohashi, K.

S. Tane, J. Kohno, J. Horikoshi, K. Kondo, K. Ohashi, A. Komatsu, T. Kakehashi, “The Study on the Microscopic Biometry of the Thickness of the Human Retina, Choroid and Sclera by Ultrasound,” Acta Soc. Ophthalmol. Jpn. 88, 1412 (1984).

Pankratov, M. M.

Parker, J. S.

F. Delori, J. S. Parker, M. A. Mainster, “Light Levels in Fundus Photography and Fluorescein Angiography,” Vision Res. 20, 1099 (1980).
[CrossRef] [PubMed]

Parrish, J. A.

R. R. Anderson, J. A. Parrish, “The Optics of Human Skin,” J. Invest. Dermatol. 77, 13 (1981).
[CrossRef] [PubMed]

Persad, S.

I. A. Menon, S. Persad, H. F. Haberman, C. J. Kurian, P. K. Basu, “A Qualitative Study of the Melanins from Blue and Brown Human Eyes,” Exp. Eye Res. 34, 531 (1982).
[CrossRef] [PubMed]

Pflibsen, K. P.

Pitts, S. M.

R. W. Flower, D. S. McLeod, S. M. Pitts, “Reflection of Light by Small Areas of the Ocular Fundus,” Invest. Ophthalmol. Vis. Sci. 16, 981 (1977).
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Plibsen, K. P.

F. C. Delori, K. P. Plibsen, “Reflectance Properties of the Optic Disc,” Noninvasive Assessment of the Visual System. OSA Technical Digest, in press.

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Pruett, R. C.

F. C. Delori, E. S. Gragoudas, R. Francisco, R. C. Pruett, “Monochromatic Ophthalmoscopy and Fundus Photography,” Arch. Ophthalmol. 95, 861 (1977).
[CrossRef] [PubMed]

Read, J. S.

P. E. Kilbride, J. S. Read, G. A. Fishman, M. Fishman, “Determination of Human Cone Pigment Density Difference Spectra in Spatially Resolved Regions of the Fovea,” Vision Res. 12, 1341 (1983).
[CrossRef]

Rohler, R.

R. Rohler, U. Miller, M. Aberl, “Zur Messung der Modulationsiibertragungsfunktion des Lebenden Menschlichen Auges im Reflektierten Licht,” Vision Res. 9, 407 (1969).
[CrossRef] [PubMed]

Rushton, W. A.

W. A. Rushton, G. H. Henri, “Bleaching and Regeneration of Cone Pigments in Man,” Vision Res. 8, 617 (1968).
[CrossRef] [PubMed]

Schmidt, F. H.

W. J. Geeraets, R. C. Williams, G. Chan, W. T. Ham, D. Guerry, F. H. Schmidt, “The Relative Absorption of Thermal Energy in Retina and Choroid,” Invest. Ophthalmol. 1, 340 (1962).
[PubMed]

Smith, R. S.

R. S. Smith, M. N. Stein, “Ocular Hazards of Transscleral Laser Radiation. I. Spectral Reflection and Transmission of the Sclera, Choroid and Retina,” Am. J. Ophthalmol. 66, 21 (1968).
[PubMed]

Snodderly, D. M.

D. M. Snodderly, P. K. Brown, F. C. Delori, J. D. Auran, “The Macular Pigment. I. Absorbance Spectra, Localization, and Discrimination from Other Yellow Pigments in Primate Retinas,” Invest. Ophthalmol. Vis. Sci. 25, 660 (1984).
[PubMed]

Sparrock, J. M. B.

R. A. Bone, J. M. B. Sparrock, “Comparison of Macular Pigment Densities in Human Eyes,” Vision Res. 11, 1057 (1971).
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Sperber, G.

A. Bill, G. Sperber, K. Ujiie, “Physiology of the Choroidal Vascular Bed,” Int. Ophthalmol. 6, 101 (1983).
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Stein, M. N.

R. S. Smith, M. N. Stein, “Ocular Hazards of Transscleral Laser Radiation. I. Spectral Reflection and Transmission of the Sclera, Choroid and Retina,” Am. J. Ophthalmol. 66, 21 (1968).
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Takatani, S.

S. Takatani, M. D. Graham, “Theoretical Analysis of Diffuse Reflectance from a Two-Layer Tissue Model,” IEEE Trans. Biomed. Eng. BME-26, 656 (1979).
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Tane, S.

S. Tane, J. Kohno, J. Horikoshi, K. Kondo, K. Ohashi, A. Komatsu, T. Kakehashi, “The Study on the Microscopic Biometry of the Thickness of the Human Retina, Choroid and Sclera by Ultrasound,” Acta Soc. Ophthalmol. Jpn. 88, 1412 (1984).

Thompson, S.

Tiemeijer, L. F.

D. van Norren, L. F. Tiemeijer, “Spectral Reflectance of the Human Eye,” Vision Res. 26, 313 (1986).
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Trokel, S.

S. Trokel, “Quantitative Studies of Choroidal Blood Flow by Reflective Densitometry,” Invest. Ophthalmol. 4, 1129 (1965).
[PubMed]

Ujiie, K.

A. Bill, G. Sperber, K. Ujiie, “Physiology of the Choroidal Vascular Bed,” Int. Ophthalmol. 6, 101 (1983).
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O. W. van Assendelft, Spectroscopy of Hemoglobin Derivatives (C. C. Thomas, Springfield, IL, 1970).

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D. van Norren, J. van der Kraats, “A Continuously Recording Retinal Densitometer,” Vision Res. 21, 897 (1981).
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D. van Norren, L. F. Tiemeijer, “Spectral Reflectance of the Human Eye,” Vision Res. 26, 313 (1986).
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D. van Norren, J. van der Kraats, “A Continuously Recording Retinal Densitometer,” Vision Res. 21, 897 (1981).
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D. van Norren, J. J. Vos, “Spectral Transmission of the Human Ocular Media,” Vision Res. 14, 1237 (1974).
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Vos, J. J.

D. van Norren, J. J. Vos, “Spectral Transmission of the Human Ocular Media,” Vision Res. 14, 1237 (1974).
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J. J. Vos, A. A. Munnik, J. Boogaard, “Absolute Spectral Reflectance of the Fundus Oculi,” J. Opt. Soc. Am. 55, 573 (1965).
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Walraven, J.

J. Walraven, “Spatial Characteristics of Chromatic Induction: the Segregation of Lateral Effects from Straylight Artefacts,” Vision Res. 13, 1739 (1973).
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Wasserman, W.

J. Neter, W. Wasserman, M. H. Kutner, Applied Linear Statistical Models (Richard D. Irwin, Inc., Homewood, IL, 1985), p. 580.

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R. A. Weale, “Polarized Light and the Human Fundus Oculi,” J. Physiol. 186, 175 (1966).
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Weddell, J. E.

M. J. Hogan, J. A. Alvarado, J. E. Weddell, Histology of the Human Eye (Saunders, Philadelphia, 1971).

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J. J. Weiter, F. C. Delori, G. L. Wing, K. A. Fitch, “Retinal Pigment Epithelium Lipofuscin and Melanin and Choroidal Melanin in Human Eyes,” Invest. Ophthalmol. Vis. Sci. 27, 145 (1986).
[PubMed]

Williams, R. C.

W. J. Geeraets, R. C. Williams, G. Chan, W. T. Ham, D. Guerry, F. H. Schmidt, “The Relative Absorption of Thermal Energy in Retina and Choroid,” Invest. Ophthalmol. 1, 340 (1962).
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Willmer, E. N.

G. S. Brindley, E. N. Willmer, “The Reflection of Light from the Macular and Peripheral Fundus Oculi in Man,” J. Physiol. (London) 116, 350 (1952).

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J. J. Weiter, F. C. Delori, G. L. Wing, K. A. Fitch, “Retinal Pigment Epithelium Lipofuscin and Melanin and Choroidal Melanin in Human Eyes,” Invest. Ophthalmol. Vis. Sci. 27, 145 (1986).
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Wodick, R.

D. W. Lubbers, R. Wodick, “Absolute Reflection Photometry Applied to the Measurement of Capillary Oxyhaemoglobin Saturation of the Skin in Man,” Oxygen Meas. Biol. Med. 1, 85 (1974).

Wolter, J. R.

E. A. Boetner, J. R. Wolter, “Transmission of the Ocular Media,” Invest. Ophthalmol. 1, 776 (1962).

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R. L. Longini, R. Zdrojkowski, “A Note on the Theory of Backscattering of Light by Living Tissue,” IEEE Trans. Biomed. Eng. BME-15, 4 (1968).
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Zeimer, R. C.

M. T. Mori, R. C. Zeimer, M. F. Goldberg, “Noninvasive Measurement of Retinal Thickness: a Potential Diagnostic Tool for Macular Edema and Atrophy,” Invest. Ophthalmol. Vis. Sci. 29 (ARVO Suppl), 339 (1988).

R. C. Zeimer, U. Illinois, Research Eye Institute; personal communication (June1988).

Acta Soc. Ophthalmol. Jpn. (1)

S. Tane, J. Kohno, J. Horikoshi, K. Kondo, K. Ohashi, A. Komatsu, T. Kakehashi, “The Study on the Microscopic Biometry of the Thickness of the Human Retina, Choroid and Sclera by Ultrasound,” Acta Soc. Ophthalmol. Jpn. 88, 1412 (1984).

Am. J. Ophthalmol. (2)

D. J. Coleman, F. L. Lizzi, “In vivo Choroidal Thickness Measurement,” Am. J. Ophthalmol. 88, 369 (1979).
[PubMed]

R. S. Smith, M. N. Stein, “Ocular Hazards of Transscleral Laser Radiation. I. Spectral Reflection and Transmission of the Sclera, Choroid and Retina,” Am. J. Ophthalmol. 66, 21 (1968).
[PubMed]

Am. J. Optom. Physiol. Opt. (1)

D. O’Leary, M. Millodot, “The Discrepancy Between Retinoscopic and Subjective Refraction: Effect of Light Polarization,” Am. J. Optom. Physiol. Opt. 55, 553 (1978).
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Appl. Opt. (2)

Arch. Ophthalmol. (2)

T. Behrendt, T. D. Duane, “Investigation of Fundus Oculi with Spectral Reflectance Photography. I: Depth and Integrity of Fundal Structures,” Arch. Ophthalmol. 75, 375 (1966).
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F. C. Delori, E. S. Gragoudas, R. Francisco, R. C. Pruett, “Monochromatic Ophthalmoscopy and Fundus Photography,” Arch. Ophthalmol. 95, 861 (1977).
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Atti Fond. Giorgio Ronchi (1)

M. Millodot, “Reflection from the Fundus of the Eye and Its Relevance to Retinoscopy,” Atti Fond. Giorgio Ronchi 27, 31 (1972).

Biochim. Biophys. Acta (1)

L. N. M. Duysens, “The Flattening of the Absorption Spectrum of Suspensions, as Compared to that of Solutions,” Biochim. Biophys. Acta 19, 1 (1956).
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Br. J. Physiol. Opt. (1)

W. N. Charman, “Reflection of Plane-Polarized Light by the Retina,” Br. J. Physiol. Opt. 34, 34 (1980).
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Doc. Ophthalmol. (1)

N. H. Bakker, “Fundus Reflectometry, an Experimental Study,” Doc. Ophthalmol. 38, 271 (1974).
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Exp. Eye Res. (2)

J. Gloster, “Fundus Oximetry,” Exp. Eye Res. 6, 187 (1967).
[CrossRef] [PubMed]

I. A. Menon, S. Persad, H. F. Haberman, C. J. Kurian, P. K. Basu, “A Qualitative Study of the Melanins from Blue and Brown Human Eyes,” Exp. Eye Res. 34, 531 (1982).
[CrossRef] [PubMed]

IEEE Trans. Biomed. Eng. (2)

R. L. Longini, R. Zdrojkowski, “A Note on the Theory of Backscattering of Light by Living Tissue,” IEEE Trans. Biomed. Eng. BME-15, 4 (1968).
[CrossRef]

S. Takatani, M. D. Graham, “Theoretical Analysis of Diffuse Reflectance from a Two-Layer Tissue Model,” IEEE Trans. Biomed. Eng. BME-26, 656 (1979).
[CrossRef]

Int. Ophthalmol. (2)

A. Bill, G. Sperber, K. Ujiie, “Physiology of the Choroidal Vascular Bed,” Int. Ophthalmol. 6, 101 (1983).
[CrossRef] [PubMed]

J. Gloster, “Fundus Reflectometry in the Study of the Choroidal Circulation,” Int. Ophthalmol. 6, 109 (1983).
[CrossRef] [PubMed]

Invest. Ophthalmol. (3)

S. Trokel, “Quantitative Studies of Choroidal Blood Flow by Reflective Densitometry,” Invest. Ophthalmol. 4, 1129 (1965).
[PubMed]

W. J. Geeraets, R. C. Williams, G. Chan, W. T. Ham, D. Guerry, F. H. Schmidt, “The Relative Absorption of Thermal Energy in Retina and Choroid,” Invest. Ophthalmol. 1, 340 (1962).
[PubMed]

E. A. Boetner, J. R. Wolter, “Transmission of the Ocular Media,” Invest. Ophthalmol. 1, 776 (1962).

Invest. Ophthalmol. Vis. Sci. (3)

D. M. Snodderly, P. K. Brown, F. C. Delori, J. D. Auran, “The Macular Pigment. I. Absorbance Spectra, Localization, and Discrimination from Other Yellow Pigments in Primate Retinas,” Invest. Ophthalmol. Vis. Sci. 25, 660 (1984).
[PubMed]

J. J. Weiter, F. C. Delori, G. L. Wing, K. A. Fitch, “Retinal Pigment Epithelium Lipofuscin and Melanin and Choroidal Melanin in Human Eyes,” Invest. Ophthalmol. Vis. Sci. 27, 145 (1986).
[PubMed]

R. W. Flower, D. S. McLeod, S. M. Pitts, “Reflection of Light by Small Areas of the Ocular Fundus,” Invest. Ophthalmol. Vis. Sci. 16, 981 (1977).
[PubMed]

Invest. Ophthalmol. Vis. Sci. 29 (ARVO Suppl) (1)

M. T. Mori, R. C. Zeimer, M. F. Goldberg, “Noninvasive Measurement of Retinal Thickness: a Potential Diagnostic Tool for Macular Edema and Atrophy,” Invest. Ophthalmol. Vis. Sci. 29 (ARVO Suppl), 339 (1988).

J. Invest. Dermatol. (1)

R. R. Anderson, J. A. Parrish, “The Optics of Human Skin,” J. Invest. Dermatol. 77, 13 (1981).
[CrossRef] [PubMed]

J. Opt. Soc. Am. (2)

J. Physiol. (1)

R. A. Weale, “Polarized Light and the Human Fundus Oculi,” J. Physiol. 186, 175 (1966).
[PubMed]

J. Physiol. (London) (1)

G. S. Brindley, E. N. Willmer, “The Reflection of Light from the Macular and Peripheral Fundus Oculi in Man,” J. Physiol. (London) 116, 350 (1952).

Ophthalmic Res. (1)

W. Hunold, P. Malessa, “Spectrophotometric Determination of Melanin Pigmentation of the Human Ocular Fundus in vivo,” Ophthalmic Res. 6, 355 (1974).
[CrossRef]

Oxygen Meas. Biol. Med. (1)

D. W. Lubbers, R. Wodick, “Absolute Reflection Photometry Applied to the Measurement of Capillary Oxyhaemoglobin Saturation of the Skin in Man,” Oxygen Meas. Biol. Med. 1, 85 (1974).

Vision Res. (13)

R. A. Bone, J. M. B. Sparrock, “Comparison of Macular Pigment Densities in Human Eyes,” Vision Res. 11, 1057 (1971).
[CrossRef] [PubMed]

J. Walraven, “Spatial Characteristics of Chromatic Induction: the Segregation of Lateral Effects from Straylight Artefacts,” Vision Res. 13, 1739 (1973).
[CrossRef] [PubMed]

K. R. Alexander, P. E. Kilbride, G. A. Fishman, M. Fishman, “Macular Pigment and Reduced Foveal Short-Wavelength Sensitivity in Retinitis Pigmentosa,” Vision Res. 27, 1077 (1987).
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R. Rohler, U. Miller, M. Aberl, “Zur Messung der Modulationsiibertragungsfunktion des Lebenden Menschlichen Auges im Reflektierten Licht,” Vision Res. 9, 407 (1969).
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W. N. Charman, J. A. M. Jennings, “Objective Measurements of the Longitudinal Chromatic Aberration of the Human Eye,” Vision Res. 16, 999 (1976).
[CrossRef] [PubMed]

J.-M. Gorrand, R. Alfieri, J.-Y. Boire, “Diffusion of the Retinal Layers of the Living Human Eye,” Vision Res. 24, 1097 (1984).
[CrossRef] [PubMed]

D. van Norren, L. F. Tiemeijer, “Spectral Reflectance of the Human Eye,” Vision Res. 26, 313 (1986).
[CrossRef] [PubMed]

D. van Norren, J. van der Kraats, “A Continuously Recording Retinal Densitometer,” Vision Res. 21, 897 (1981).
[CrossRef] [PubMed]

D. J. Faulkner, C. M. Kemp, “Human Rhodopsin Measurement Using a T.V.-Based Imaging Fundus Reflectometer,” Vision Res. 24, 221 (1984).
[CrossRef] [PubMed]

P. E. Kilbride, J. S. Read, G. A. Fishman, M. Fishman, “Determination of Human Cone Pigment Density Difference Spectra in Spatially Resolved Regions of the Fovea,” Vision Res. 12, 1341 (1983).
[CrossRef]

W. A. Rushton, G. H. Henri, “Bleaching and Regeneration of Cone Pigments in Man,” Vision Res. 8, 617 (1968).
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[CrossRef]

Other (12)

F. C. Delori, K. P. Plibsen, “Reflectance Properties of the Optic Disc,” Noninvasive Assessment of the Visual System. OSA Technical Digest, in press.

P. R. Bevington, Data Reduction and Error Analysis for the Physical Sciences (McGraw-Hill, New York, 1969), p. 235.

Determination of pigment concentrations requires a tight fit both in red light (melanin) and in green light (hemoglobin). Because of the large differences in reflectance in those two spectral bands (Fig. 2), such fit could be achieved by minimizing the relative errors or by using a weight Wλ=Robs, λ−2 in Eq. (2). However, a lesser weight might be desired for short wavelengths to minimize the effect of inaccuracies caused by ocular media light scattering, low signal-to-noise ratio, etc. We therefore selected Wλ=Robs,λ−1 as a compromise.

J. Neter, W. Wasserman, M. H. Kutner, Applied Linear Statistical Models (Richard D. Irwin, Inc., Homewood, IL, 1985), p. 580.

V. P. Gabel, R. Birngruber, F. Hillekamp, “Visible and Near Infrared Light Absorption in Pigment Epithelium and Choroid,” in Twenty-Third Concilium Ophthalmologicum, Kyoto, K. Shimizu, Ed. (Excerpta Medica, Amsterdam, 1978).

American National Standards Institute, “Safe Use of Lasers,” Z136.1 (ANSI, New York, 1976).

The in vitro measurements of Weiter et al.36 were made with polychromatic light in the 500–600-nm spectral range. Using the melanin absorption spectrum of Fig. 4 (solid curve), we calculated that the absorption coefficient at 500 nm should be about 1.6 times higher than those reported in Weiter’s study.

W. Lerche, “Die Kapillarisierung der Menschlichen Retina,” in Eye Structure, II Symposium, J. W. Rohen, Ed. (Schattauer-Verlag, Stuttgart, 1965).

O. W. van Assendelft, Spectroscopy of Hemoglobin Derivatives (C. C. Thomas, Springfield, IL, 1970).

M. J. Hogan, J. A. Alvarado, J. E. Weddell, Histology of the Human Eye (Saunders, Philadelphia, 1971).

R. C. Zeimer, U. Illinois, Research Eye Institute; personal communication (June1988).

G. Kortum, Reflectance Spectroscopy (Springer-Verlag, New York, 1969), p. 116.

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Figures (11)

Fig. 1
Fig. 1

Diagram of the experimental fundus reflectometer. See text for explanation of symbols. Unmarked components are stan dard optical parts of the fundus camera.

Fig. 2
Fig. 2

Reflectance spectra from the nasal fundus (N), the perifovea (P), and the fovea (F) in ten subjects (1–10) with different degrees of ocular melanin pigmentation. Subjects 1–8 were Caucasians with blue irises (1,2,3), green or hazel irises (4,5,6), brown irises (7,8), and subjects 9 and 10 were Black. The illumination area was 5° in diameter in all cases, and the sampling area was ~4° for the nasal data and ~1.6° for the macular data.

Fig. 3
Fig. 3

Top, reflectance spectra from subject 2 for an area superior to the arcuate bundle (spectrum 1), for an area centered on the fovea (spectrum 5), and for three equally spaced areas between the previous sites (spectra 2–4). Bottom, reflectance spectra from subject 4 in an area centered on a choroidal nevus (N) and from an area adjacent to the nevus (S). These spectra were offset by a factor of 10 toward lower reflectances to avoid overlap with the other spectra. The reflectance in the 530–580-nm range was slightly higher for N than for S. Examination of fundus photographs showed slight alteration in the RPE in the area of the nevus. Both sets of spectra were obtained with an illumination aperture of 5° and a sampling area of ~4°.

Fig. 4
Fig. 4

Absorption characteristics of the ocular pigments. HbO2, oxygenated hemoglobin, data from van Assendelft39; right scale, extinction coefficients of hemoglobin with an oxygen saturation of 95% (hemoglobin concentration: 15 mg/100 mliter). Data were averaged over the 7-nm bandwidth of the reflectometer. ME, melanin, data from Gabel et al.33 and Menon et al.34 (solid line) and from Geeraets et al.35 (interrupted line), representing extremes in the rate of spectral dependence; relative scale. MP, macular pigment, data from Snodderly et al.44 ; left scale, approximate optical density in humans. OM, ocular media, data of van Norren and Vos27; left scale, optical density for the standard observer.

Fig. 5
Fig. 5

Schematic reflectance spectrum from the fundus with the hypothetical spectrum R λ *. The R λ * spectrum drawn through the 455-, 540-, and 575-nm points of the real spectrum ( log R λ * ) always shows a slight negative curvature. The log R λ * spectrum represents fundus reflectance if blood were replaced by a spectrally neutral absorber with extinction coefficient K h b * (= Khb,455 = Khb,540 = Khb,575, see Fig. 4). This spectrum is influenced by melanin absorption, ocular media transmission, etc., but not by spectral changes in blood absorption. Because of the low curvature of log R λ * one can assume that log R λ * varies linearly with λ beween 540 and 610 nm, and log R λ * can then be calculated by intra- or extrapolation along a line through the 540- and 575-nm points. The differences, at 560 and 610 nm, between the log R λ * and the log R λ * spectra are used in Eq. (6) to estimate the amount of blood responsible for the hemoglobin spectral signature on the fundus spectra.

Fig. 6
Fig. 6

Reflectance spectra from the nasal fundus (N) in three subjects with age as indicated. The 74-yr old subject was aphakic; the other two subjects were phakic. CO, reflectance spectrum from a coloboma in the 74-yr old aphakic subject. These measurements were obtained with an illumination aperture of 5° and a sampling area of 4°. SC, reflectance from the sclera at the conjunctiva in a young subject (2). This measurement is relative as no absolute reference was used in this instance. The absorption bands of blood from the conjunctival capillaries are clearly seen; the interrupted line is the R λ * spectrum associated with the SC spectrum (see Sec. IV.A.2). These spectra demonstrate that scleral reflectance decreases continuously with increasing wavelength.

Fig. 7
Fig. 7

Fundus photograph obtained using oblique illumination of the fundus. An illuminating fiber optics was applied on the conjunctiva. The angle of incidence of light at the posterior pole of the eye was estimated to be 30°, and the projected direction is indicated by an arrow. The distance between the vessel and its shadow is 149 ± 10 μm (average of sixteen sites). The shadow is formed on a surface located ~140/tan (30°) or 240 μm posterior to the vessels.

Fig. 8
Fig. 8

(a) Schematic representation of the fundus layers: om, ocular media; ilm, inner limiting membrane; phr, photoreceptors; rpe, retinal pigmented ephithelium; bm, Bruch’s membrane; cc, choriocapillaris; chs, choroidal stroma; and sc, sclera. (b) and (c) Diagrams for model II and model III, respectively. Parameters with an asterisk are fixed; the others are adjusted by curve fitting in each model. The D symbols represent single-pass densities, r, reflectances, and d, blood layer thicknesses.

Fig. 9
Fig. 9

Model II results: experimental reflectance data (+)and fitted regression (solid lines) for three spectra; N1, nasal fundus of subject 1; P7, perifovea of 7; and F10, fovea of 10. The regression results (S.E. in parentheses) are given for each spectrum. The units are D.U. for Dme, Dx, and Dmp; μm for dhb; and percent reflectance for rep, and RE. The interrupted lines are spectra reconstructed from the model results in the following conditions: (a) reflectance contribution of the anterior reflector seen through the ocular media (and macular pigment) and (b) reflectance of the choroid in the absence of the anterior reflector.

Fig. 10
Fig. 10

Mean results for the average F/ratios (AFR) and for the five fitted parameters of model III, for different values of the RPE density Drpe,500. The symbols N, P, and F (for nasal fundus, perifovea, and fovea, respectively) are located adjacent to the scale corresponding with each parameter. The filled squares indicate a significant (p < 0.05) correlation between Dme,500 and the parameter; open squares indicate no significant correlation.

Fig. 11
Fig. 11

Model III results: experimental reflectance data (+) and fitted regression (solid lines) for three spectra: N1, nasal fundus of subject 1; P7, perifovea of 7; and F10, fovea of 10, The regression results (S.E. in parentheses) are given for each spectrum. The units are D.U. for Dme, Dx and Dmp; μm for dhb; and percent reflectance for rpe and RE. The interrupted lines are spectra reconstructed from the model results in the following conditions: (a) reflectance contribution of the anterior reflector seen through the ocular media (and macular pigment) and (b) reflectance of the choroid in the absence of the anterior reflector.

Tables (4)

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Table I Average Fundus Reflectance for Ten Subjects at Three Different Sites

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Table II Equivalent Blood Layer Thickness Calculated with Eq. (6) at 560 and 610 nm for Three Sites in Ten Subjects

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Table III Results of Regressions for ModeIIa

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Table IV Results of Regressions for Model IIIa

Equations (11)

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R λ = 0.019 ( n r S f , λ n f S r , λ ) ,
M = n W λ ( R obs , λ R mod , λ ) 2 ,
RE = 100 [ ( 1 / n ) n ( R obs , λ R mod , λ ) 2 / R obs , λ 2 ] 1 / 2 .
PRE = 100 [ ( 1 / n s ) s    n ( R obs , λ R mod , λ ) 2 / R obs , λ 2 ] 1 / 2 ,
log R λ = log R b , λ 2 p K p , λ d p = log R b , λ 2 p K p , λ D p , λ n ,
d h b = log R λ log R λ * 2 ( K h b , λ K h b * ) .
log R f , λ R p , λ = log R f , λ R p , λ 2 K m p , λ D m p , 460 ,
R mod , λ = 10 2 ( K o m , λ D o m , 420 + K m p , λ D m p , 460 ) [ r p e + ( 1 r p e ) r s c × 10 2 ( K m e , λ D m e , 500 + K h b d h b ) ] ,
R mod , λ = 10 2 ( K o m , λ D o m , 420   +   K m p , λ D m p , 460   +   D m s ) [ r p e   +   ( 1 r p e ) r c h × 10 2 ( K m e , λ D r p e , 500   +   K h b , λ d c c ) ] .
r c h = ( 1 r s c , λ ) ( a b coth b S t c h ) a + b coth b S t c h r s c , λ ,
a = 1 + ( D m e , 500 K m e , λ + K h b , λ d h b + D x ) log 10 e S t c h ,

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