Abstract

A noninvasive spectrophotometric technique for the measurement of oxygen saturation of the blood in discrete retinal vessels is described. The instrument, the retinal vessel oximeter, uses scanning fundus reflectometry to determine the optical density of a retinal vessel at three wavelengths (558, 569, and 586 nm). Oxygen saturation is determined after compensation for the effects of light scattering by the red blood cells by relating the measured densities with the corresponding extinction coefficients of oxyhemoglobin and deoxygenated hemoglobin. The vessel diameter is also measured continuously. All data acquisition and analysis are performed on-line by means of a microcomputer, and a vessel tracking system is used to compensate for the effects of eye movements. Oxygen saturation measurements for blood flowing through glass capillaries are presented as well as representative results of oxygen saturation measurements on normal human subjects.

© 1988 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. J. B. Hickham, R. Frayser, “A Photographic Method for Measuring the Mean Retinal Circulation Time Using Fluorescein,” Invest. Ophthalmol. 4, 876 (1965).
  2. C. E. Riva, G. T. Feke, B. Eberli, V. Benary, “Bidirectional LDV System for Absolute Measurement of Blood Speed in Retinal Vessels,” Appl. Opt. 18, 2301 (1979).
    [CrossRef] [PubMed]
  3. G. T. Feke, D. G. Goger, H. Tagawa, F. C. Delori, “Laser Doppler Technique for Absolute Measurement of Blood Speed in Retinal Vessels,” IEEE Trans. Biomed. Eng. BE-34, 673 (1987).
    [CrossRef]
  4. J. B. Hickham, R. Frayser, J. C. Ross, “A Study of Retinal Venous Blood Oxygen Saturation in Human Subjects by Photographic Means,” Circulation 27, 375 (1963).
    [CrossRef]
  5. J. B. Hickham, R. Frayser, “Studies of the Retinal Circulation in Man: Observation of Vessel Diameter, Arteriovenous Oxygen Saturation Difference, and Mean Circulation Time,” Circulation 33, 302 (1966).
    [CrossRef]
  6. R. A. Laing, A. J. Cohen, E. Friedman, “Development of Clinically Useful Methods of Estimating Choroidal and Retinal Blood Flow,” Final Report, contract NIH-NEI 711-2513, National Eye Institute, National Institutes of Health, Bethesda, MD (1974).
  7. A. J. Cohen, R. A. Laing, “Multiple Scattering Analysis of Retinal Blood Oximetry,” IEEE Trans. Biomed. Eng. BE-23, 391 (1986).
  8. R. A. Laing, A. J. Cohen, E. Friedman, “Photographic Measurements of Retinal Blood Oxygen Saturation: Falling Saturation Rabbit Experiments,” Invest. Ophthalmol. 14, 606 (1975).
    [PubMed]
  9. H. J. Klose, E. Volger, H. Brechtelsbauer, H. Schmid-Schonbein, “Microrheology and Light Transmission of Blood. I. The Photometric Effects of Red Cell Aggregation and Red Cell Orientation,” Pfluegers Arch. 333, 126 (1972).
    [CrossRef]
  10. F. C. Delori, F. J. Rogers, S. E. Bursell, J. S. Parker, “A System for Non-Invasive Oximetry of Retinal Vessels,” in Frontiers of Engineering in Health Care, 1982. Proceedings, Fourth Annual Conference of the I.E.E.E. Engineering in Medicine and Biology Society, A. R. Potvin, J. H. Potvin, Eds. (Institute of Electrical & Electronics Engineers, New York, 1982), p. 296.
  11. F. C. Delori, J. J. Weiter, M. A. Mainster, V. A. Flook, “Oxygen Saturation Measurements in Retinal Vessels,” Invest. Ophthalmol. Visual Sci. 24, (ARVO Suppl), 13 (1983).
  12. F. C. Delori, D. M. Deupree, J. J. Weiter, “Evaluation of the Retinal Vessel Oximetry Technique,” Invest. Ophthalmol. Visual Sci. 26, (ARVO Suppl), 37 (1985).
  13. R. N. Pittman, B. R. Duling, “A New Method for the Measurement of Percent Oxyhemoglobin,” J. Appl. Physiol. 38, 315 (1975).
    [PubMed]
  14. O. W. van Assendelft, Spectrophotometry of Hemoglobin Derivatives (C.C. Thomas, Springfield, IL, 1970).
  15. D. L. Drabkin, R. B. Singer, “Spectrophotometric Studies: VI. A Study of the Absorption Spectra of Non-Hemolyzed Erythrocytes and of Scattering of Light by Suspensions of Particles,” J. Biol. Chem. 129, 739 (1939).
  16. N. M. Anderson, P. Sekelj, “Light-Absorbing and Scattering Properties of Non-Hemolyzed Blood,” Phys. Med. Biol. 12, 173 (1967).
    [CrossRef] [PubMed]
  17. R. N. Pittman, B. R. Duling, “Measurement of Percent Oxyhemoglobin in the Microvasculature,” J. Appl. Physiol. 38, 321 (1975).
    [PubMed]
  18. R. A. Weale, “Polarized Light and the Human Fundus Oculi,” J. Physiol. 186, 175 (1966).
    [PubMed]
  19. F. C. Delori, E. S. Gragoudas, R. Francisco, R. C. Pruett, “Monochromatic Ophthalmology and Fundus Photography: The Normal Fundus,” Arch. Ophthalmol. 95, 861 (1977).
    [CrossRef] [PubMed]
  20. D. van Norren, L. F. Tiemeijer, “Spectral Reflectance of the Human Eye,” Vision Res. 26, 313 (1986).
    [CrossRef] [PubMed]
  21. F. C. Delori, K. Pflibsen, “Spectral Reflectance of the Human Ocular Fundus,” (in preparation).
  22. N. M. Anderson, P. Sekelj, “Reflection and Transmission of Light by Thin Films of Nonhaemolyzed Blood,” Phys. Med. Biol. 12, 185 (1967).
    [CrossRef] [PubMed]
  23. F. C. Delori, J. S. Parker, M. A. Mainster, “Light Levels in Fundus Photography and Fluorescein Angiography,” Vision Res. 20, 1099 (1980).
    [CrossRef] [PubMed]
  24. P. Horowitz, W. Hill, The Art of Electronics (Cambridge U.P., Cambridge, 1980), p. 448.
  25. F. J. Rogers, F. C. Delori, “FIFO Memory Circuit Stores Waveform Data for Monitors and Scopes,” Electron. Des. 32, No. 15, 256 (1984).
  26. J. Sebag, F. C. Delori, G. T. Feke, D. Goger, K. Fitch, H. Tagawa, D. Deupree, J. J. Weiter, J. W. McMeel, “Anterior Optic Nerve Blood Flow Decreases in Clinical Neurogenic Optic Atrophy,” Ophthalmology 93, 858 (1986).
    [PubMed]
  27. F. C. Delori, K. P. Pflibsen, K. Fitch, “Fundus Reflectometry Measurements of Choroidal Blood Volume,” Invest. Ophthalmol. Visual Sci. 28 (ARVO Suppl), 28 (1987).
  28. J. Gloster, “Fundus Oximetry,” Exp. Eye Res. 6, 187 (1967).
    [CrossRef] [PubMed]
  29. D. W. Hill, A. Crabtree, “Vascular Calibers,” Trans. Ophthalmol. Soc. UK 104, 107 (1984).
  30. F. C. Delori, G. T. Feke, A. Yoshida, J. J. Weiter, “Retinal Oxygen Delivery in Hyperoxia, “Invest. Ophthalmol. Visual Sci. 25 (ARVO Suppl), 8 (1984).
  31. F. C. Delori, J. Sebag, G. T. Feke, J. J. Weiter, “Oxygen Saturation of Retinal Veins in Optic Atrophy,” Invest. Ophthalmol. Visual Sci. 27 (ARVO Suppl), 221 (1986).

1987 (2)

G. T. Feke, D. G. Goger, H. Tagawa, F. C. Delori, “Laser Doppler Technique for Absolute Measurement of Blood Speed in Retinal Vessels,” IEEE Trans. Biomed. Eng. BE-34, 673 (1987).
[CrossRef]

F. C. Delori, K. P. Pflibsen, K. Fitch, “Fundus Reflectometry Measurements of Choroidal Blood Volume,” Invest. Ophthalmol. Visual Sci. 28 (ARVO Suppl), 28 (1987).

1986 (4)

J. Sebag, F. C. Delori, G. T. Feke, D. Goger, K. Fitch, H. Tagawa, D. Deupree, J. J. Weiter, J. W. McMeel, “Anterior Optic Nerve Blood Flow Decreases in Clinical Neurogenic Optic Atrophy,” Ophthalmology 93, 858 (1986).
[PubMed]

F. C. Delori, J. Sebag, G. T. Feke, J. J. Weiter, “Oxygen Saturation of Retinal Veins in Optic Atrophy,” Invest. Ophthalmol. Visual Sci. 27 (ARVO Suppl), 221 (1986).

A. J. Cohen, R. A. Laing, “Multiple Scattering Analysis of Retinal Blood Oximetry,” IEEE Trans. Biomed. Eng. BE-23, 391 (1986).

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

1985 (1)

F. C. Delori, D. M. Deupree, J. J. Weiter, “Evaluation of the Retinal Vessel Oximetry Technique,” Invest. Ophthalmol. Visual Sci. 26, (ARVO Suppl), 37 (1985).

1984 (3)

D. W. Hill, A. Crabtree, “Vascular Calibers,” Trans. Ophthalmol. Soc. UK 104, 107 (1984).

F. C. Delori, G. T. Feke, A. Yoshida, J. J. Weiter, “Retinal Oxygen Delivery in Hyperoxia, “Invest. Ophthalmol. Visual Sci. 25 (ARVO Suppl), 8 (1984).

F. J. Rogers, F. C. Delori, “FIFO Memory Circuit Stores Waveform Data for Monitors and Scopes,” Electron. Des. 32, No. 15, 256 (1984).

1983 (1)

F. C. Delori, J. J. Weiter, M. A. Mainster, V. A. Flook, “Oxygen Saturation Measurements in Retinal Vessels,” Invest. Ophthalmol. Visual Sci. 24, (ARVO Suppl), 13 (1983).

1980 (1)

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

1979 (1)

1977 (1)

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

1975 (3)

R. N. Pittman, B. R. Duling, “A New Method for the Measurement of Percent Oxyhemoglobin,” J. Appl. Physiol. 38, 315 (1975).
[PubMed]

R. N. Pittman, B. R. Duling, “Measurement of Percent Oxyhemoglobin in the Microvasculature,” J. Appl. Physiol. 38, 321 (1975).
[PubMed]

R. A. Laing, A. J. Cohen, E. Friedman, “Photographic Measurements of Retinal Blood Oxygen Saturation: Falling Saturation Rabbit Experiments,” Invest. Ophthalmol. 14, 606 (1975).
[PubMed]

1972 (1)

H. J. Klose, E. Volger, H. Brechtelsbauer, H. Schmid-Schonbein, “Microrheology and Light Transmission of Blood. I. The Photometric Effects of Red Cell Aggregation and Red Cell Orientation,” Pfluegers Arch. 333, 126 (1972).
[CrossRef]

1967 (3)

N. M. Anderson, P. Sekelj, “Light-Absorbing and Scattering Properties of Non-Hemolyzed Blood,” Phys. Med. Biol. 12, 173 (1967).
[CrossRef] [PubMed]

N. M. Anderson, P. Sekelj, “Reflection and Transmission of Light by Thin Films of Nonhaemolyzed Blood,” Phys. Med. Biol. 12, 185 (1967).
[CrossRef] [PubMed]

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]

J. B. Hickham, R. Frayser, “Studies of the Retinal Circulation in Man: Observation of Vessel Diameter, Arteriovenous Oxygen Saturation Difference, and Mean Circulation Time,” Circulation 33, 302 (1966).
[CrossRef]

1965 (1)

J. B. Hickham, R. Frayser, “A Photographic Method for Measuring the Mean Retinal Circulation Time Using Fluorescein,” Invest. Ophthalmol. 4, 876 (1965).

1963 (1)

J. B. Hickham, R. Frayser, J. C. Ross, “A Study of Retinal Venous Blood Oxygen Saturation in Human Subjects by Photographic Means,” Circulation 27, 375 (1963).
[CrossRef]

1939 (1)

D. L. Drabkin, R. B. Singer, “Spectrophotometric Studies: VI. A Study of the Absorption Spectra of Non-Hemolyzed Erythrocytes and of Scattering of Light by Suspensions of Particles,” J. Biol. Chem. 129, 739 (1939).

Anderson, N. M.

N. M. Anderson, P. Sekelj, “Light-Absorbing and Scattering Properties of Non-Hemolyzed Blood,” Phys. Med. Biol. 12, 173 (1967).
[CrossRef] [PubMed]

N. M. Anderson, P. Sekelj, “Reflection and Transmission of Light by Thin Films of Nonhaemolyzed Blood,” Phys. Med. Biol. 12, 185 (1967).
[CrossRef] [PubMed]

Benary, V.

Brechtelsbauer, H.

H. J. Klose, E. Volger, H. Brechtelsbauer, H. Schmid-Schonbein, “Microrheology and Light Transmission of Blood. I. The Photometric Effects of Red Cell Aggregation and Red Cell Orientation,” Pfluegers Arch. 333, 126 (1972).
[CrossRef]

Bursell, S. E.

F. C. Delori, F. J. Rogers, S. E. Bursell, J. S. Parker, “A System for Non-Invasive Oximetry of Retinal Vessels,” in Frontiers of Engineering in Health Care, 1982. Proceedings, Fourth Annual Conference of the I.E.E.E. Engineering in Medicine and Biology Society, A. R. Potvin, J. H. Potvin, Eds. (Institute of Electrical & Electronics Engineers, New York, 1982), p. 296.

Cohen, A. J.

A. J. Cohen, R. A. Laing, “Multiple Scattering Analysis of Retinal Blood Oximetry,” IEEE Trans. Biomed. Eng. BE-23, 391 (1986).

R. A. Laing, A. J. Cohen, E. Friedman, “Photographic Measurements of Retinal Blood Oxygen Saturation: Falling Saturation Rabbit Experiments,” Invest. Ophthalmol. 14, 606 (1975).
[PubMed]

R. A. Laing, A. J. Cohen, E. Friedman, “Development of Clinically Useful Methods of Estimating Choroidal and Retinal Blood Flow,” Final Report, contract NIH-NEI 711-2513, National Eye Institute, National Institutes of Health, Bethesda, MD (1974).

Crabtree, A.

D. W. Hill, A. Crabtree, “Vascular Calibers,” Trans. Ophthalmol. Soc. UK 104, 107 (1984).

Delori, F. C.

F. C. Delori, K. P. Pflibsen, K. Fitch, “Fundus Reflectometry Measurements of Choroidal Blood Volume,” Invest. Ophthalmol. Visual Sci. 28 (ARVO Suppl), 28 (1987).

G. T. Feke, D. G. Goger, H. Tagawa, F. C. Delori, “Laser Doppler Technique for Absolute Measurement of Blood Speed in Retinal Vessels,” IEEE Trans. Biomed. Eng. BE-34, 673 (1987).
[CrossRef]

J. Sebag, F. C. Delori, G. T. Feke, D. Goger, K. Fitch, H. Tagawa, D. Deupree, J. J. Weiter, J. W. McMeel, “Anterior Optic Nerve Blood Flow Decreases in Clinical Neurogenic Optic Atrophy,” Ophthalmology 93, 858 (1986).
[PubMed]

F. C. Delori, J. Sebag, G. T. Feke, J. J. Weiter, “Oxygen Saturation of Retinal Veins in Optic Atrophy,” Invest. Ophthalmol. Visual Sci. 27 (ARVO Suppl), 221 (1986).

F. C. Delori, D. M. Deupree, J. J. Weiter, “Evaluation of the Retinal Vessel Oximetry Technique,” Invest. Ophthalmol. Visual Sci. 26, (ARVO Suppl), 37 (1985).

F. J. Rogers, F. C. Delori, “FIFO Memory Circuit Stores Waveform Data for Monitors and Scopes,” Electron. Des. 32, No. 15, 256 (1984).

F. C. Delori, G. T. Feke, A. Yoshida, J. J. Weiter, “Retinal Oxygen Delivery in Hyperoxia, “Invest. Ophthalmol. Visual Sci. 25 (ARVO Suppl), 8 (1984).

F. C. Delori, J. J. Weiter, M. A. Mainster, V. A. Flook, “Oxygen Saturation Measurements in Retinal Vessels,” Invest. Ophthalmol. Visual Sci. 24, (ARVO Suppl), 13 (1983).

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

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

F. C. Delori, K. Pflibsen, “Spectral Reflectance of the Human Ocular Fundus,” (in preparation).

F. C. Delori, F. J. Rogers, S. E. Bursell, J. S. Parker, “A System for Non-Invasive Oximetry of Retinal Vessels,” in Frontiers of Engineering in Health Care, 1982. Proceedings, Fourth Annual Conference of the I.E.E.E. Engineering in Medicine and Biology Society, A. R. Potvin, J. H. Potvin, Eds. (Institute of Electrical & Electronics Engineers, New York, 1982), p. 296.

Deupree, D.

J. Sebag, F. C. Delori, G. T. Feke, D. Goger, K. Fitch, H. Tagawa, D. Deupree, J. J. Weiter, J. W. McMeel, “Anterior Optic Nerve Blood Flow Decreases in Clinical Neurogenic Optic Atrophy,” Ophthalmology 93, 858 (1986).
[PubMed]

Deupree, D. M.

F. C. Delori, D. M. Deupree, J. J. Weiter, “Evaluation of the Retinal Vessel Oximetry Technique,” Invest. Ophthalmol. Visual Sci. 26, (ARVO Suppl), 37 (1985).

Drabkin, D. L.

D. L. Drabkin, R. B. Singer, “Spectrophotometric Studies: VI. A Study of the Absorption Spectra of Non-Hemolyzed Erythrocytes and of Scattering of Light by Suspensions of Particles,” J. Biol. Chem. 129, 739 (1939).

Duling, B. R.

R. N. Pittman, B. R. Duling, “A New Method for the Measurement of Percent Oxyhemoglobin,” J. Appl. Physiol. 38, 315 (1975).
[PubMed]

R. N. Pittman, B. R. Duling, “Measurement of Percent Oxyhemoglobin in the Microvasculature,” J. Appl. Physiol. 38, 321 (1975).
[PubMed]

Eberli, B.

Feke, G. T.

G. T. Feke, D. G. Goger, H. Tagawa, F. C. Delori, “Laser Doppler Technique for Absolute Measurement of Blood Speed in Retinal Vessels,” IEEE Trans. Biomed. Eng. BE-34, 673 (1987).
[CrossRef]

J. Sebag, F. C. Delori, G. T. Feke, D. Goger, K. Fitch, H. Tagawa, D. Deupree, J. J. Weiter, J. W. McMeel, “Anterior Optic Nerve Blood Flow Decreases in Clinical Neurogenic Optic Atrophy,” Ophthalmology 93, 858 (1986).
[PubMed]

F. C. Delori, J. Sebag, G. T. Feke, J. J. Weiter, “Oxygen Saturation of Retinal Veins in Optic Atrophy,” Invest. Ophthalmol. Visual Sci. 27 (ARVO Suppl), 221 (1986).

F. C. Delori, G. T. Feke, A. Yoshida, J. J. Weiter, “Retinal Oxygen Delivery in Hyperoxia, “Invest. Ophthalmol. Visual Sci. 25 (ARVO Suppl), 8 (1984).

C. E. Riva, G. T. Feke, B. Eberli, V. Benary, “Bidirectional LDV System for Absolute Measurement of Blood Speed in Retinal Vessels,” Appl. Opt. 18, 2301 (1979).
[CrossRef] [PubMed]

Fitch, K.

F. C. Delori, K. P. Pflibsen, K. Fitch, “Fundus Reflectometry Measurements of Choroidal Blood Volume,” Invest. Ophthalmol. Visual Sci. 28 (ARVO Suppl), 28 (1987).

J. Sebag, F. C. Delori, G. T. Feke, D. Goger, K. Fitch, H. Tagawa, D. Deupree, J. J. Weiter, J. W. McMeel, “Anterior Optic Nerve Blood Flow Decreases in Clinical Neurogenic Optic Atrophy,” Ophthalmology 93, 858 (1986).
[PubMed]

Flook, V. A.

F. C. Delori, J. J. Weiter, M. A. Mainster, V. A. Flook, “Oxygen Saturation Measurements in Retinal Vessels,” Invest. Ophthalmol. Visual Sci. 24, (ARVO Suppl), 13 (1983).

Francisco, R.

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

Frayser, R.

J. B. Hickham, R. Frayser, “Studies of the Retinal Circulation in Man: Observation of Vessel Diameter, Arteriovenous Oxygen Saturation Difference, and Mean Circulation Time,” Circulation 33, 302 (1966).
[CrossRef]

J. B. Hickham, R. Frayser, “A Photographic Method for Measuring the Mean Retinal Circulation Time Using Fluorescein,” Invest. Ophthalmol. 4, 876 (1965).

J. B. Hickham, R. Frayser, J. C. Ross, “A Study of Retinal Venous Blood Oxygen Saturation in Human Subjects by Photographic Means,” Circulation 27, 375 (1963).
[CrossRef]

Friedman, E.

R. A. Laing, A. J. Cohen, E. Friedman, “Photographic Measurements of Retinal Blood Oxygen Saturation: Falling Saturation Rabbit Experiments,” Invest. Ophthalmol. 14, 606 (1975).
[PubMed]

R. A. Laing, A. J. Cohen, E. Friedman, “Development of Clinically Useful Methods of Estimating Choroidal and Retinal Blood Flow,” Final Report, contract NIH-NEI 711-2513, National Eye Institute, National Institutes of Health, Bethesda, MD (1974).

Gloster, J.

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

Goger, D.

J. Sebag, F. C. Delori, G. T. Feke, D. Goger, K. Fitch, H. Tagawa, D. Deupree, J. J. Weiter, J. W. McMeel, “Anterior Optic Nerve Blood Flow Decreases in Clinical Neurogenic Optic Atrophy,” Ophthalmology 93, 858 (1986).
[PubMed]

Goger, D. G.

G. T. Feke, D. G. Goger, H. Tagawa, F. C. Delori, “Laser Doppler Technique for Absolute Measurement of Blood Speed in Retinal Vessels,” IEEE Trans. Biomed. Eng. BE-34, 673 (1987).
[CrossRef]

Gragoudas, E. S.

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

Hickham, J. B.

J. B. Hickham, R. Frayser, “Studies of the Retinal Circulation in Man: Observation of Vessel Diameter, Arteriovenous Oxygen Saturation Difference, and Mean Circulation Time,” Circulation 33, 302 (1966).
[CrossRef]

J. B. Hickham, R. Frayser, “A Photographic Method for Measuring the Mean Retinal Circulation Time Using Fluorescein,” Invest. Ophthalmol. 4, 876 (1965).

J. B. Hickham, R. Frayser, J. C. Ross, “A Study of Retinal Venous Blood Oxygen Saturation in Human Subjects by Photographic Means,” Circulation 27, 375 (1963).
[CrossRef]

Hill, D. W.

D. W. Hill, A. Crabtree, “Vascular Calibers,” Trans. Ophthalmol. Soc. UK 104, 107 (1984).

Hill, W.

P. Horowitz, W. Hill, The Art of Electronics (Cambridge U.P., Cambridge, 1980), p. 448.

Horowitz, P.

P. Horowitz, W. Hill, The Art of Electronics (Cambridge U.P., Cambridge, 1980), p. 448.

Klose, H. J.

H. J. Klose, E. Volger, H. Brechtelsbauer, H. Schmid-Schonbein, “Microrheology and Light Transmission of Blood. I. The Photometric Effects of Red Cell Aggregation and Red Cell Orientation,” Pfluegers Arch. 333, 126 (1972).
[CrossRef]

Laing, R. A.

A. J. Cohen, R. A. Laing, “Multiple Scattering Analysis of Retinal Blood Oximetry,” IEEE Trans. Biomed. Eng. BE-23, 391 (1986).

R. A. Laing, A. J. Cohen, E. Friedman, “Photographic Measurements of Retinal Blood Oxygen Saturation: Falling Saturation Rabbit Experiments,” Invest. Ophthalmol. 14, 606 (1975).
[PubMed]

R. A. Laing, A. J. Cohen, E. Friedman, “Development of Clinically Useful Methods of Estimating Choroidal and Retinal Blood Flow,” Final Report, contract NIH-NEI 711-2513, National Eye Institute, National Institutes of Health, Bethesda, MD (1974).

Mainster, M. A.

F. C. Delori, J. J. Weiter, M. A. Mainster, V. A. Flook, “Oxygen Saturation Measurements in Retinal Vessels,” Invest. Ophthalmol. Visual Sci. 24, (ARVO Suppl), 13 (1983).

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

McMeel, J. W.

J. Sebag, F. C. Delori, G. T. Feke, D. Goger, K. Fitch, H. Tagawa, D. Deupree, J. J. Weiter, J. W. McMeel, “Anterior Optic Nerve Blood Flow Decreases in Clinical Neurogenic Optic Atrophy,” Ophthalmology 93, 858 (1986).
[PubMed]

Parker, J. S.

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

F. C. Delori, F. J. Rogers, S. E. Bursell, J. S. Parker, “A System for Non-Invasive Oximetry of Retinal Vessels,” in Frontiers of Engineering in Health Care, 1982. Proceedings, Fourth Annual Conference of the I.E.E.E. Engineering in Medicine and Biology Society, A. R. Potvin, J. H. Potvin, Eds. (Institute of Electrical & Electronics Engineers, New York, 1982), p. 296.

Pflibsen, K.

F. C. Delori, K. Pflibsen, “Spectral Reflectance of the Human Ocular Fundus,” (in preparation).

Pflibsen, K. P.

F. C. Delori, K. P. Pflibsen, K. Fitch, “Fundus Reflectometry Measurements of Choroidal Blood Volume,” Invest. Ophthalmol. Visual Sci. 28 (ARVO Suppl), 28 (1987).

Pittman, R. N.

R. N. Pittman, B. R. Duling, “A New Method for the Measurement of Percent Oxyhemoglobin,” J. Appl. Physiol. 38, 315 (1975).
[PubMed]

R. N. Pittman, B. R. Duling, “Measurement of Percent Oxyhemoglobin in the Microvasculature,” J. Appl. Physiol. 38, 321 (1975).
[PubMed]

Pruett, R. C.

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

Riva, C. E.

Rogers, F. J.

F. J. Rogers, F. C. Delori, “FIFO Memory Circuit Stores Waveform Data for Monitors and Scopes,” Electron. Des. 32, No. 15, 256 (1984).

F. C. Delori, F. J. Rogers, S. E. Bursell, J. S. Parker, “A System for Non-Invasive Oximetry of Retinal Vessels,” in Frontiers of Engineering in Health Care, 1982. Proceedings, Fourth Annual Conference of the I.E.E.E. Engineering in Medicine and Biology Society, A. R. Potvin, J. H. Potvin, Eds. (Institute of Electrical & Electronics Engineers, New York, 1982), p. 296.

Ross, J. C.

J. B. Hickham, R. Frayser, J. C. Ross, “A Study of Retinal Venous Blood Oxygen Saturation in Human Subjects by Photographic Means,” Circulation 27, 375 (1963).
[CrossRef]

Schmid-Schonbein, H.

H. J. Klose, E. Volger, H. Brechtelsbauer, H. Schmid-Schonbein, “Microrheology and Light Transmission of Blood. I. The Photometric Effects of Red Cell Aggregation and Red Cell Orientation,” Pfluegers Arch. 333, 126 (1972).
[CrossRef]

Sebag, J.

J. Sebag, F. C. Delori, G. T. Feke, D. Goger, K. Fitch, H. Tagawa, D. Deupree, J. J. Weiter, J. W. McMeel, “Anterior Optic Nerve Blood Flow Decreases in Clinical Neurogenic Optic Atrophy,” Ophthalmology 93, 858 (1986).
[PubMed]

F. C. Delori, J. Sebag, G. T. Feke, J. J. Weiter, “Oxygen Saturation of Retinal Veins in Optic Atrophy,” Invest. Ophthalmol. Visual Sci. 27 (ARVO Suppl), 221 (1986).

Sekelj, P.

N. M. Anderson, P. Sekelj, “Reflection and Transmission of Light by Thin Films of Nonhaemolyzed Blood,” Phys. Med. Biol. 12, 185 (1967).
[CrossRef] [PubMed]

N. M. Anderson, P. Sekelj, “Light-Absorbing and Scattering Properties of Non-Hemolyzed Blood,” Phys. Med. Biol. 12, 173 (1967).
[CrossRef] [PubMed]

Singer, R. B.

D. L. Drabkin, R. B. Singer, “Spectrophotometric Studies: VI. A Study of the Absorption Spectra of Non-Hemolyzed Erythrocytes and of Scattering of Light by Suspensions of Particles,” J. Biol. Chem. 129, 739 (1939).

Tagawa, H.

G. T. Feke, D. G. Goger, H. Tagawa, F. C. Delori, “Laser Doppler Technique for Absolute Measurement of Blood Speed in Retinal Vessels,” IEEE Trans. Biomed. Eng. BE-34, 673 (1987).
[CrossRef]

J. Sebag, F. C. Delori, G. T. Feke, D. Goger, K. Fitch, H. Tagawa, D. Deupree, J. J. Weiter, J. W. McMeel, “Anterior Optic Nerve Blood Flow Decreases in Clinical Neurogenic Optic Atrophy,” Ophthalmology 93, 858 (1986).
[PubMed]

Tiemeijer, L. F.

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

van Assendelft, O. W.

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

van Norren, D.

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

Volger, E.

H. J. Klose, E. Volger, H. Brechtelsbauer, H. Schmid-Schonbein, “Microrheology and Light Transmission of Blood. I. The Photometric Effects of Red Cell Aggregation and Red Cell Orientation,” Pfluegers Arch. 333, 126 (1972).
[CrossRef]

Weale, R. A.

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

Weiter, J. J.

J. Sebag, F. C. Delori, G. T. Feke, D. Goger, K. Fitch, H. Tagawa, D. Deupree, J. J. Weiter, J. W. McMeel, “Anterior Optic Nerve Blood Flow Decreases in Clinical Neurogenic Optic Atrophy,” Ophthalmology 93, 858 (1986).
[PubMed]

F. C. Delori, J. Sebag, G. T. Feke, J. J. Weiter, “Oxygen Saturation of Retinal Veins in Optic Atrophy,” Invest. Ophthalmol. Visual Sci. 27 (ARVO Suppl), 221 (1986).

F. C. Delori, D. M. Deupree, J. J. Weiter, “Evaluation of the Retinal Vessel Oximetry Technique,” Invest. Ophthalmol. Visual Sci. 26, (ARVO Suppl), 37 (1985).

F. C. Delori, G. T. Feke, A. Yoshida, J. J. Weiter, “Retinal Oxygen Delivery in Hyperoxia, “Invest. Ophthalmol. Visual Sci. 25 (ARVO Suppl), 8 (1984).

F. C. Delori, J. J. Weiter, M. A. Mainster, V. A. Flook, “Oxygen Saturation Measurements in Retinal Vessels,” Invest. Ophthalmol. Visual Sci. 24, (ARVO Suppl), 13 (1983).

Yoshida, A.

F. C. Delori, G. T. Feke, A. Yoshida, J. J. Weiter, “Retinal Oxygen Delivery in Hyperoxia, “Invest. Ophthalmol. Visual Sci. 25 (ARVO Suppl), 8 (1984).

Appl. Opt. (1)

Arch. Ophthalmol. (1)

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

Circulation (2)

J. B. Hickham, R. Frayser, J. C. Ross, “A Study of Retinal Venous Blood Oxygen Saturation in Human Subjects by Photographic Means,” Circulation 27, 375 (1963).
[CrossRef]

J. B. Hickham, R. Frayser, “Studies of the Retinal Circulation in Man: Observation of Vessel Diameter, Arteriovenous Oxygen Saturation Difference, and Mean Circulation Time,” Circulation 33, 302 (1966).
[CrossRef]

Electron. Des. (1)

F. J. Rogers, F. C. Delori, “FIFO Memory Circuit Stores Waveform Data for Monitors and Scopes,” Electron. Des. 32, No. 15, 256 (1984).

Exp. Eye Res. (1)

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

IEEE Trans. Biomed. Eng. (2)

G. T. Feke, D. G. Goger, H. Tagawa, F. C. Delori, “Laser Doppler Technique for Absolute Measurement of Blood Speed in Retinal Vessels,” IEEE Trans. Biomed. Eng. BE-34, 673 (1987).
[CrossRef]

A. J. Cohen, R. A. Laing, “Multiple Scattering Analysis of Retinal Blood Oximetry,” IEEE Trans. Biomed. Eng. BE-23, 391 (1986).

Invest. Ophthalmol. (2)

R. A. Laing, A. J. Cohen, E. Friedman, “Photographic Measurements of Retinal Blood Oxygen Saturation: Falling Saturation Rabbit Experiments,” Invest. Ophthalmol. 14, 606 (1975).
[PubMed]

J. B. Hickham, R. Frayser, “A Photographic Method for Measuring the Mean Retinal Circulation Time Using Fluorescein,” Invest. Ophthalmol. 4, 876 (1965).

Invest. Ophthalmol. Visual Sci. (5)

F. C. Delori, K. P. Pflibsen, K. Fitch, “Fundus Reflectometry Measurements of Choroidal Blood Volume,” Invest. Ophthalmol. Visual Sci. 28 (ARVO Suppl), 28 (1987).

F. C. Delori, G. T. Feke, A. Yoshida, J. J. Weiter, “Retinal Oxygen Delivery in Hyperoxia, “Invest. Ophthalmol. Visual Sci. 25 (ARVO Suppl), 8 (1984).

F. C. Delori, J. Sebag, G. T. Feke, J. J. Weiter, “Oxygen Saturation of Retinal Veins in Optic Atrophy,” Invest. Ophthalmol. Visual Sci. 27 (ARVO Suppl), 221 (1986).

F. C. Delori, J. J. Weiter, M. A. Mainster, V. A. Flook, “Oxygen Saturation Measurements in Retinal Vessels,” Invest. Ophthalmol. Visual Sci. 24, (ARVO Suppl), 13 (1983).

F. C. Delori, D. M. Deupree, J. J. Weiter, “Evaluation of the Retinal Vessel Oximetry Technique,” Invest. Ophthalmol. Visual Sci. 26, (ARVO Suppl), 37 (1985).

J. Appl. Physiol. (2)

R. N. Pittman, B. R. Duling, “A New Method for the Measurement of Percent Oxyhemoglobin,” J. Appl. Physiol. 38, 315 (1975).
[PubMed]

R. N. Pittman, B. R. Duling, “Measurement of Percent Oxyhemoglobin in the Microvasculature,” J. Appl. Physiol. 38, 321 (1975).
[PubMed]

J. Biol. Chem. (1)

D. L. Drabkin, R. B. Singer, “Spectrophotometric Studies: VI. A Study of the Absorption Spectra of Non-Hemolyzed Erythrocytes and of Scattering of Light by Suspensions of Particles,” J. Biol. Chem. 129, 739 (1939).

J. Physiol. (1)

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

Ophthalmology (1)

J. Sebag, F. C. Delori, G. T. Feke, D. Goger, K. Fitch, H. Tagawa, D. Deupree, J. J. Weiter, J. W. McMeel, “Anterior Optic Nerve Blood Flow Decreases in Clinical Neurogenic Optic Atrophy,” Ophthalmology 93, 858 (1986).
[PubMed]

Pfluegers Arch. (1)

H. J. Klose, E. Volger, H. Brechtelsbauer, H. Schmid-Schonbein, “Microrheology and Light Transmission of Blood. I. The Photometric Effects of Red Cell Aggregation and Red Cell Orientation,” Pfluegers Arch. 333, 126 (1972).
[CrossRef]

Phys. Med. Biol. (2)

N. M. Anderson, P. Sekelj, “Light-Absorbing and Scattering Properties of Non-Hemolyzed Blood,” Phys. Med. Biol. 12, 173 (1967).
[CrossRef] [PubMed]

N. M. Anderson, P. Sekelj, “Reflection and Transmission of Light by Thin Films of Nonhaemolyzed Blood,” Phys. Med. Biol. 12, 185 (1967).
[CrossRef] [PubMed]

Trans. Ophthalmol. Soc. UK (1)

D. W. Hill, A. Crabtree, “Vascular Calibers,” Trans. Ophthalmol. Soc. UK 104, 107 (1984).

Vision Res. (2)

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

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

Other (5)

F. C. Delori, K. Pflibsen, “Spectral Reflectance of the Human Ocular Fundus,” (in preparation).

P. Horowitz, W. Hill, The Art of Electronics (Cambridge U.P., Cambridge, 1980), p. 448.

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

F. C. Delori, F. J. Rogers, S. E. Bursell, J. S. Parker, “A System for Non-Invasive Oximetry of Retinal Vessels,” in Frontiers of Engineering in Health Care, 1982. Proceedings, Fourth Annual Conference of the I.E.E.E. Engineering in Medicine and Biology Society, A. R. Potvin, J. H. Potvin, Eds. (Institute of Electrical & Electronics Engineers, New York, 1982), p. 296.

R. A. Laing, A. J. Cohen, E. Friedman, “Development of Clinically Useful Methods of Estimating Choroidal and Retinal Blood Flow,” Final Report, contract NIH-NEI 711-2513, National Eye Institute, National Institutes of Health, Bethesda, MD (1974).

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 (12)

Fig. 1
Fig. 1

Spectral variation of the specific extinction coefficients (left scale) of oxygenated hemoglobin (HbO2) and deoxygenated hemoglobin (Hb). Data are from van Assendelft.14 The extinction coefficients (right scale) were calculated for a total hemoglobin concentration of 15 g/100 mliter or 8.98 μmole/mliter.

Fig. 2
Fig. 2

Variation of blood column density vs extinction coefficient for oxygenated blood flowing through a 100-μm glass capillary located in front of a diffuse (filled squares) or specular (open squares) reflector. For the diffuse reflector data, each point is the mean of measurements on seven blood samples and corresponds to the wavelength given at the top. Error bars represent ±SD. Error bars for the extinction coefficients were omitted for clarity (the coefficient of variation was ~3.6% for all green wavelengths, increasing to 7% at 650 nm). Least-squares fit to Eq. (2) of the data in the 510–590-nm wavelength range (solid line) yielded S = 0.325 D.U. and s.d. = 0.0073 cm (r2 = 0.992, p < 0.0001). Least-squares fit of the same data to a second-degree equation revealed a slight but not significant (p = 0.19) negative curvature. For the specular reflector data, each point is the mean of measurements on two blood samples made at only four wavelengths. Least-squares fit to Eq. (2) of the data for the three shorter wavelengths (interrupted line) yielded S = 0.88 D.U. and s.d. = 0.0040 cm (r2 = 0.98, p < 0.05).

Fig. 3
Fig. 3

Interrelationship between the measured vessel density Dλ, the specific extinction coefficient Eλ, and the wavelength λ. The two diagrams represent (a) the D-E characteristic and the D-E line [Eq. (4)] (the latter is a linear approximation of the D-E characteristic in the narrow range of extinction coefficients used) and (b) a section of the absorption spectra (Fig. 1) for oxygenated (HbO2) and deoxygenated (Hb) hemoglobin. A graphic solution of the three-wavelength method is represented by the interrupted lines. Vessel density measurements D569 and D586 at the two isobestic wavelengths with known extinction coefficients Er,569 and Er,586569 = Δ586 = 0) define the points M and N of the D-E line (intercept α and slope β). The extinction coefficient E558 is not known but varies between extreme values Eo,558 (O2Sat. = 100%) and Er,558 (O2Sat. = 0%). The third density measurement D558 gives point S on the D-E line and hence the unknown extinction value. O2Sat. is derived by linear interpolation, which is represented by the small O2Sat. scale along the Eλ axis. The slope β of the D-E line reflects the sensitivity for detection of changes in hemoglobin absorption.

Fig. 4
Fig. 4

Fundus photograph of a normal subject illustrating the size of the scanned field around a retinal vein within the restricted illumination area used during oximetry. Retinal veins are larger and darker than arteries, and both show an irregular linear reflex, which is caused by specular reflection at the inner limiting membrane of the retina. In general, the optic disk is ~1800 μm in diameter, and the diameter of the largest vessels is ~150–200 μm for veins and 120–140 μm for arteries.

Fig. 5
Fig. 5

Schematic diagram of the optics and electronics of the retinal vessel oximeter system. The orientation of the vessel scanner is drawn for the case of a vertically oriented retinal vessel (in the plane of the drawing). The symbol × refers to planes conjugated with the entrance pupil of the optical system (which is adjusted to be in the patient’s pupil) and the symbol + to planes conjugated with the patient’s retina. Unlabeled components represent lens systems (light shading) or other optical components of the Zeiss fundus camera. See text for explanation of symbols.

Fig. 6
Fig. 6

Timing diagram of various signals in relation to the presence of the four wavelength filters (0, 1, 2, 3 at top) in the illumination beam: s, the filter wheel sensors signals; b, the blanking signal; r, the ramp signal driving the galvanometric scanner; and υ, the vessel profiles at successive wavelengths. The step decrease of the ramp signal during flyback minimizes oscillations of the mirror. The sequence of data acquisition in the 8088 coprocessor, transfer to the 6502 microprocessor, and analysis of the different wavelength scans are indicated by the bars. After scan analysis is completed, the 6502 microprocessor waits until the acquisition of the next wavelength is completed.

Fig. 7
Fig. 7

Flow chart of the computer program of the 6502 microprocessor. The program consists of a sequence of data acquisition and accumulation of the four wavelength scans and a sequence of detailed analysis of the accumulated profiles. B and N are base line and accumulation counters, respectively. (4W?) checks that all four wavelengths have undergone a particular operation. The interrupted lines refer to operation of the RVO in the reflectance mode (R mode). The symbols y and n indicate a yes or no answer to a particular question.

Fig. 8
Fig. 8

(a) Typical reflection profile of a vessel as recorded in array SHI (192 channels). The intercepts of the VDL with the vessel profile are used to define the vessel center C midway between the intercepts. Fixed sections of the profile ZL (on the leading side of C) and ZT (on the trailing side of C) are selected for accumulation (ZL + ZT = 144 channels). The vessel edges b and vessel minima υ, as well as the HHL, are determined for each scan. (b) Possible patterns of the recorded scan illustrating scan acceptance (1) or scan rejection (0) for the selected mode L (leading) or T (trailing). The vertical lines indicate the selected vessel. (c) Accumulated profile corresponding with the 569-nm wavelength (144 channels). EL and ET: edges of the scan; BL and BT: background edges; SL and ST: positions of maximal slope; ML and MT: vessel profile minima; VL and VT: points located at half-height between the S and M points on each side of the profile. At this and other wavelengths, background reflection is integrated in the two zones marked B and vessel reflection in the two zones marked V. Also derived from the profile analysis are the vessel diameter VD and the reflex factor ρ defined as r/mean background signal.

Fig. 9
Fig. 9

Spectral distributions F558, F569, and F586 for the three spectral bands used in oximetry (solid lines, arbitrary scale). Specific extinction coefficients (dash–dotted lines, left scale) of oxygenated hemoglobin (HbO2) and deoxygenated hemoglobin (Hb).14 Fundus reflectance spectra21 for different degrees of fundus pigmentations (dashed lines, right scale) with corresponding reflectance factor γ [defined by Eq. (8)] between γ = 0.05 (dark fundus) and γ = 0.50 (light fundus).

Fig. 10
Fig. 10

Relationship of O2Sat. and measured operator RP [Eq. (6)] for extreme values of vessel diameter (shaded areas: 70 and 150 μm) and of the reflectance factor γ (0–0.4; for a spectrally uniform background to that of a lightly pigmented fundus).

Fig. 11
Fig. 11

(a) RVO output traces of O2Sat. measurements for blood flowing through a 100-μm glass capillary positioned in front of a diffuse background. Each point represents one determination or 1.6 s of data acquisition and analysis. The traces correspond to five blood samples (from one subject) oxygenated at different levels and also measured by standardized CO oximetry. The O2Sat. measured with the CO oximeter is shown by lines and given in bold type at the top of each trace, whereas values given in plain type correspond to the RVO measurement, which is the average of 10–15 determinations (SD: 1.3–2.4% O2Sat.). (b) Comparison of O2Sat. measured by the RVO and the CO oximeter for various combinations of capillary diameter and background reflector. The key indicates, for each symbol, the nature of the background reflector (D, diffuse; S, specular), the diameter in micrometers, and the number of blood samples measured (in parentheses). The dotted line shows the equality of O2Sat. measured by the two methods.

Fig. 12
Fig. 12

(a) RVO recording showing O2Sat. (top traces) and vessel diameter (bottom traces) for four veins and four arteries in one normal subject (age: 33). Each point represents one determination or ~1.6–3 s of data acquisition and analysis. Average values for each group of determinations are given at the top of each trace for arteries and at the bottom of each trace for veins. The standard deviations for the O2Sat. and vessel diameter measurements were 3.5 to 5.9% O2Sat. and 1.3–2.0 μm, respectively. The reflectance factor γ ranged between 0.21 and 0.35, reflecting differences in local pigmentation of the fundus. (b) O2Sat. and vessel diameter response to breathing 100% O2 in one subject (age: 35). The measurements were made alternately on the artery A and on the vein V of a vascular segment, and the average results are given as in (a). The standard deviations for the O2Sat. and vessel diameter measurements were 2.4–4.3% O22Sat. and 0.5–2.3 μm, respectively (excluding the venous data during the rapid change). The results show no detectable change in arterial O2Sat. but a substantial increase in venous O2Sat. (from ~42 to 65 O2Sat.). Pronounced vasoconstriction of both the artery (by ~10%) and the vein (by ~14%) is observed. The factor γ was ~0.15 for the fundus background at both vessels. O2Sat. calculations took the changes in vessel diameter into account [Eq. (9)].

Tables (1)

Tables Icon

Table I Characteristics of the Spectral Bands used for Oximetry and Parameters used in Eq. (9) for the Calculation of the Average Specific Extinction Coefficients of Hemoglobin

Equations (10)

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

E λ = E o · O 2 Sat . + E r · ( 1 O 2 Sat . ) = E r + Δ λ · O 2 Sat . ,
D λ = S + s . C . d · ( E r , λ + Δ λ · O 2 Sat . ) ,
T λ = V λ / B λ and D λ = log ( T λ ) .
D λ = α + β · ( E r , λ + Δ λ · O 2 Sat . ) ,
RP = D 569 D 558 D 569 D 586 = log ( T 558 / T 569 ) log ( T 586 / T 569 ) ,
O 2 Sat . = 100 · ( E r , 569 E r , 558 ) + ( E r , 586 E r , 569 ) · RP ( Δ 558 Δ 569 ) + ( Δ 569 Δ 586 ) · RP ,
E λ = 1 s . C . d · log R b , λ · F λ · 10 s . C . d . E λ · Δ λ R b , λ · F λ · Δ λ ,
γ = R b , 586 R b , 569 1 .
E λ = A 0 + A 1 · γ + A 2 · C . d + A 3 · γ 2 + A 4 · ( C . d ) 2 + A 5 · γ · C . d
O 2 Sat . RVO = ( 0 . 8 + 4 . 1 · I br + 33 · C . d ) + 0 . 95 · O 2 Sat . CO , p < 0 . 0001 p < 0 . 008 p < 0 . 0001

Metrics