Abstract

The argon laser for diabetic retinopathy therapy was originally selected for photocoagulation by matching peak emission to hemoglobin absorption to maximize obliteration of retinal blood vessels. Present clinical experience in the treatment of diabetic retinopathy does not show any marked advantage of argon lasers over ruby and xenon photocoagulators not matched to hemoglobin absorption. The efficacy of photocoagulation is shown to depend upon the interaction between choroidal and retinal blood supplies in tissue oxygenation and depends upon pigment epithelium absorption to destroy rods and cones. Design specifications for new laser photocoagulators and alternative (supplemental) therapy for diabetic retinopathy are given.

© 1979 Optical Society of America

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  1. G. Meyer-Schwickerath, Light Coagulation (Mosby, St. Louis, 1960).
  2. G. Meyer-Schwickerath, Trans. Ophthalmol. Soc. UK 84, 67 (1964).
  3. F. A. L’Esperance, Arch. Ophthalmol. 75, 61 (1966).
    [CrossRef]
  4. T. H. Maiman, Nature 187, 493 (1959).
    [CrossRef]
  5. M. Flocks, H. C. Zweng, Arch. Ophthalmol. 72, 604 (1964).
    [CrossRef]
  6. N. S. Kapany, N. A. Peppers, H. C. Zweng, M. Flocks, Nature 199, 146 (1963).
    [CrossRef]
  7. N. S. Kapany, N. Silbertrust, N. A. Peppers, Appl. Opt. 4, 517 (1965).
    [CrossRef]
  8. H. C. Zweng, M. Flocks, N. S. Kapany, N. Silbertrust, N. A. Peppers, Am. J. Ophthalmol. 58, 353 (1964).
  9. C. J. Campbell, M. C. Rittler, C. J. Koester, Trans. Am. Acad. Ophthalmol. Otolaryngol. 67, 58 (1963).
  10. C. J. Koester, E. Snitzer, C. J. Campbell, M. C. Rittler, J. Opt. Soc. Am. 52, 607 (1962).
  11. W. T. Ham, R. C. Williams, W. J. Geeraets, R. S. Ruffin, H. A. Mueller, Acta Ophthalmol. (Suppl.) 76, 60 (1963).
  12. M. M. Zaret, G. M. Breinin, H. Schmidt, H. Ripps, I. M. Siegel, L. R. Solon, Science 134, 1525 (1961).
    [CrossRef] [PubMed]
  13. M. M. Zaret, H. Ripps, I. M. Siegel, G. M. Breinin, Arch. Ophthalmol. 69, 97 (1963).
    [CrossRef]
  14. F. A. L’Esperance, Arch. Ophthalmol. 74, 752 (1965).
    [CrossRef]
  15. F. A. L’Esperance, Trans. Am. Ophthalmol. Soc. 66, 827 (1968).
  16. N. Peppers, SRI International; personal communication (1977).
  17. F. Fankhauser, W. Lotmar, Ophthalmologica 175, 105 (1977).
    [CrossRef] [PubMed]
  18. F. Ederer, R. Hiller, Survey Ophthalmol. 19, 267 (1975).
  19. Diabetic Retinopathy Study Research Group, Am. J. Ophthalmol. 81, 1 (1976).
    [PubMed]
  20. M. L. Wolbarsht, M. B. Landers, Fed. Proc. 37, 242 (1978).
  21. M. L. Wolbarsht, M. B. Landers, L. Rand, Invest. Ophthalmol. Vis. Sci. 71, Suppl. 224 (1978).
  22. A. Bill, in Adler’s Physiology of the Eye, R. A. Moses, Ed. (Mosby, St. Louis, 1975), pp. 210–231.
  23. E. Friedman, in Controversy in Ophthalmology (Saunders, Philadelphia, 1977).
  24. J. T. Ernest, A. M. Potts, Am. J. Ophthalmol. 72, 435 (1971).
  25. A. Patz, Survey Ophthalmol. 12, 1 (1969).
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    [PubMed]
  27. I. C. Michaelson, Trans. Ophthalmol. Soc. UK 68, 137 (1948).
  28. G. N. Wise, Trans. Am. Ophthalmol. Soc. 54, 729 (1956).
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  30. J. Ditzel, Microvascular Res. 8, 259 (1974).
  31. J. Ditzel, E. Standl, Acta Med. Scand. 578 (Suppl.), 59 (1975).
  32. N. C. Staub, Circ. Res. 43, 143 (1978).
    [CrossRef] [PubMed]
  33. E. M. Kohner, Acta Med. Scand. 578 (Suppl.), 41 (1975).
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    [CrossRef] [PubMed]
  35. H. H. Lipowsky, S. Kovalcheck, B. Zweifach, Circ. Res. 43, 738 (1978).
    [CrossRef] [PubMed]
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    [CrossRef] [PubMed]
  37. F. Skovberg, A. V. Nielson, J. S. Krull, Scand. J. Clin. Lab. Invest. 21, 83 (1968).
    [CrossRef]
  38. H. Lipowsky, B. Zweifach, Microvasc. Res. 7, 73 (1974).
    [CrossRef] [PubMed]
  39. T. Kuwabara, L. Aiello, in Symposium on Treatment of Diabetic Retinopathy, M. Goldberg, S. Fine, Eds. (U.S. Dept. HEW, Arlington, 1968).

1978

M. L. Wolbarsht, M. B. Landers, Fed. Proc. 37, 242 (1978).

M. L. Wolbarsht, M. B. Landers, L. Rand, Invest. Ophthalmol. Vis. Sci. 71, Suppl. 224 (1978).

A. Patz, S. Brem, D. Finkelstein et al., Am. Acad. Ophthalmol. Otolaryngol. 85, 626 (1978).

N. C. Staub, Circ. Res. 43, 143 (1978).
[CrossRef] [PubMed]

H. H. Lipowsky, S. Kovalcheck, B. Zweifach, Circ. Res. 43, 738 (1978).
[CrossRef] [PubMed]

1977

H. H. Lipowsky, B. Zweifach, Microvasc. Res. 14, 345 (1977).
[CrossRef] [PubMed]

F. Fankhauser, W. Lotmar, Ophthalmologica 175, 105 (1977).
[CrossRef] [PubMed]

1976

Diabetic Retinopathy Study Research Group, Am. J. Ophthalmol. 81, 1 (1976).
[PubMed]

1975

F. Ederer, R. Hiller, Survey Ophthalmol. 19, 267 (1975).

E. M. Kohner, Acta Med. Scand. 578 (Suppl.), 41 (1975).

J. Ditzel, E. Standl, Acta Med. Scand. 578 (Suppl.), 59 (1975).

1974

J. Ditzel, Microvascular Res. 8, 259 (1974).

B. Zweifach, Circ. Res. 34, 843 (1974).
[CrossRef] [PubMed]

H. Lipowsky, B. Zweifach, Microvasc. Res. 7, 73 (1974).
[CrossRef] [PubMed]

1971

J. T. Ernest, A. M. Potts, Am. J. Ophthalmol. 72, 435 (1971).

1970

N. Ashton, Br. Med. Bull. 26, 103 (1970).
[PubMed]

1969

A. Patz, Survey Ophthalmol. 12, 1 (1969).

1968

F. A. L’Esperance, Trans. Am. Ophthalmol. Soc. 66, 827 (1968).

F. Skovberg, A. V. Nielson, J. S. Krull, Scand. J. Clin. Lab. Invest. 21, 83 (1968).
[CrossRef]

1966

F. A. L’Esperance, Arch. Ophthalmol. 75, 61 (1966).
[CrossRef]

1965

1964

H. C. Zweng, M. Flocks, N. S. Kapany, N. Silbertrust, N. A. Peppers, Am. J. Ophthalmol. 58, 353 (1964).

M. Flocks, H. C. Zweng, Arch. Ophthalmol. 72, 604 (1964).
[CrossRef]

G. Meyer-Schwickerath, Trans. Ophthalmol. Soc. UK 84, 67 (1964).

1963

N. S. Kapany, N. A. Peppers, H. C. Zweng, M. Flocks, Nature 199, 146 (1963).
[CrossRef]

C. J. Campbell, M. C. Rittler, C. J. Koester, Trans. Am. Acad. Ophthalmol. Otolaryngol. 67, 58 (1963).

W. T. Ham, R. C. Williams, W. J. Geeraets, R. S. Ruffin, H. A. Mueller, Acta Ophthalmol. (Suppl.) 76, 60 (1963).

M. M. Zaret, H. Ripps, I. M. Siegel, G. M. Breinin, Arch. Ophthalmol. 69, 97 (1963).
[CrossRef]

1962

C. J. Koester, E. Snitzer, C. J. Campbell, M. C. Rittler, J. Opt. Soc. Am. 52, 607 (1962).

1961

M. M. Zaret, G. M. Breinin, H. Schmidt, H. Ripps, I. M. Siegel, L. R. Solon, Science 134, 1525 (1961).
[CrossRef] [PubMed]

1959

T. H. Maiman, Nature 187, 493 (1959).
[CrossRef]

1956

G. N. Wise, Trans. Am. Ophthalmol. Soc. 54, 729 (1956).

1948

I. C. Michaelson, Trans. Ophthalmol. Soc. UK 68, 137 (1948).

Aiello, L.

T. Kuwabara, L. Aiello, in Symposium on Treatment of Diabetic Retinopathy, M. Goldberg, S. Fine, Eds. (U.S. Dept. HEW, Arlington, 1968).

Ashton, N.

N. Ashton, Br. Med. Bull. 26, 103 (1970).
[PubMed]

Bill, A.

A. Bill, in Adler’s Physiology of the Eye, R. A. Moses, Ed. (Mosby, St. Louis, 1975), pp. 210–231.

Breinin, G. M.

M. M. Zaret, H. Ripps, I. M. Siegel, G. M. Breinin, Arch. Ophthalmol. 69, 97 (1963).
[CrossRef]

M. M. Zaret, G. M. Breinin, H. Schmidt, H. Ripps, I. M. Siegel, L. R. Solon, Science 134, 1525 (1961).
[CrossRef] [PubMed]

Brem, S.

A. Patz, S. Brem, D. Finkelstein et al., Am. Acad. Ophthalmol. Otolaryngol. 85, 626 (1978).

Campbell, C. J.

C. J. Campbell, M. C. Rittler, C. J. Koester, Trans. Am. Acad. Ophthalmol. Otolaryngol. 67, 58 (1963).

C. J. Koester, E. Snitzer, C. J. Campbell, M. C. Rittler, J. Opt. Soc. Am. 52, 607 (1962).

Ditzel, J.

J. Ditzel, E. Standl, Acta Med. Scand. 578 (Suppl.), 59 (1975).

J. Ditzel, Microvascular Res. 8, 259 (1974).

Ederer, F.

F. Ederer, R. Hiller, Survey Ophthalmol. 19, 267 (1975).

Ernest, J. T.

J. T. Ernest, A. M. Potts, Am. J. Ophthalmol. 72, 435 (1971).

Fankhauser, F.

F. Fankhauser, W. Lotmar, Ophthalmologica 175, 105 (1977).
[CrossRef] [PubMed]

Finkelstein, D.

A. Patz, S. Brem, D. Finkelstein et al., Am. Acad. Ophthalmol. Otolaryngol. 85, 626 (1978).

Flocks, M.

H. C. Zweng, M. Flocks, N. S. Kapany, N. Silbertrust, N. A. Peppers, Am. J. Ophthalmol. 58, 353 (1964).

M. Flocks, H. C. Zweng, Arch. Ophthalmol. 72, 604 (1964).
[CrossRef]

N. S. Kapany, N. A. Peppers, H. C. Zweng, M. Flocks, Nature 199, 146 (1963).
[CrossRef]

Friedman, E.

E. Friedman, in Controversy in Ophthalmology (Saunders, Philadelphia, 1977).

Geeraets, W. J.

W. T. Ham, R. C. Williams, W. J. Geeraets, R. S. Ruffin, H. A. Mueller, Acta Ophthalmol. (Suppl.) 76, 60 (1963).

Ham, W. T.

W. T. Ham, R. C. Williams, W. J. Geeraets, R. S. Ruffin, H. A. Mueller, Acta Ophthalmol. (Suppl.) 76, 60 (1963).

Hiller, R.

F. Ederer, R. Hiller, Survey Ophthalmol. 19, 267 (1975).

Kapany, N. S.

N. S. Kapany, N. Silbertrust, N. A. Peppers, Appl. Opt. 4, 517 (1965).
[CrossRef]

H. C. Zweng, M. Flocks, N. S. Kapany, N. Silbertrust, N. A. Peppers, Am. J. Ophthalmol. 58, 353 (1964).

N. S. Kapany, N. A. Peppers, H. C. Zweng, M. Flocks, Nature 199, 146 (1963).
[CrossRef]

Koester, C. J.

C. J. Campbell, M. C. Rittler, C. J. Koester, Trans. Am. Acad. Ophthalmol. Otolaryngol. 67, 58 (1963).

C. J. Koester, E. Snitzer, C. J. Campbell, M. C. Rittler, J. Opt. Soc. Am. 52, 607 (1962).

Kohner, E. M.

E. M. Kohner, Acta Med. Scand. 578 (Suppl.), 41 (1975).

Kovalcheck, S.

H. H. Lipowsky, S. Kovalcheck, B. Zweifach, Circ. Res. 43, 738 (1978).
[CrossRef] [PubMed]

Krull, J. S.

F. Skovberg, A. V. Nielson, J. S. Krull, Scand. J. Clin. Lab. Invest. 21, 83 (1968).
[CrossRef]

Kuwabara, T.

T. Kuwabara, L. Aiello, in Symposium on Treatment of Diabetic Retinopathy, M. Goldberg, S. Fine, Eds. (U.S. Dept. HEW, Arlington, 1968).

L’Esperance, F. A.

F. A. L’Esperance, Trans. Am. Ophthalmol. Soc. 66, 827 (1968).

F. A. L’Esperance, Arch. Ophthalmol. 75, 61 (1966).
[CrossRef]

F. A. L’Esperance, Arch. Ophthalmol. 74, 752 (1965).
[CrossRef]

Landers, M. B.

M. L. Wolbarsht, M. B. Landers, Fed. Proc. 37, 242 (1978).

M. L. Wolbarsht, M. B. Landers, L. Rand, Invest. Ophthalmol. Vis. Sci. 71, Suppl. 224 (1978).

Lipowsky, H.

H. Lipowsky, B. Zweifach, Microvasc. Res. 7, 73 (1974).
[CrossRef] [PubMed]

Lipowsky, H. H.

H. H. Lipowsky, S. Kovalcheck, B. Zweifach, Circ. Res. 43, 738 (1978).
[CrossRef] [PubMed]

H. H. Lipowsky, B. Zweifach, Microvasc. Res. 14, 345 (1977).
[CrossRef] [PubMed]

Lotmar, W.

F. Fankhauser, W. Lotmar, Ophthalmologica 175, 105 (1977).
[CrossRef] [PubMed]

Maiman, T. H.

T. H. Maiman, Nature 187, 493 (1959).
[CrossRef]

Meyer-Schwickerath, G.

G. Meyer-Schwickerath, Trans. Ophthalmol. Soc. UK 84, 67 (1964).

G. Meyer-Schwickerath, Light Coagulation (Mosby, St. Louis, 1960).

Michaelson, I. C.

I. C. Michaelson, Trans. Ophthalmol. Soc. UK 68, 137 (1948).

Mueller, H. A.

W. T. Ham, R. C. Williams, W. J. Geeraets, R. S. Ruffin, H. A. Mueller, Acta Ophthalmol. (Suppl.) 76, 60 (1963).

Nielson, A. V.

F. Skovberg, A. V. Nielson, J. S. Krull, Scand. J. Clin. Lab. Invest. 21, 83 (1968).
[CrossRef]

Patz, A.

A. Patz, S. Brem, D. Finkelstein et al., Am. Acad. Ophthalmol. Otolaryngol. 85, 626 (1978).

A. Patz, Survey Ophthalmol. 12, 1 (1969).

Peppers, N.

N. Peppers, SRI International; personal communication (1977).

Peppers, N. A.

N. S. Kapany, N. Silbertrust, N. A. Peppers, Appl. Opt. 4, 517 (1965).
[CrossRef]

H. C. Zweng, M. Flocks, N. S. Kapany, N. Silbertrust, N. A. Peppers, Am. J. Ophthalmol. 58, 353 (1964).

N. S. Kapany, N. A. Peppers, H. C. Zweng, M. Flocks, Nature 199, 146 (1963).
[CrossRef]

Potts, A. M.

J. T. Ernest, A. M. Potts, Am. J. Ophthalmol. 72, 435 (1971).

Rand, L.

M. L. Wolbarsht, M. B. Landers, L. Rand, Invest. Ophthalmol. Vis. Sci. 71, Suppl. 224 (1978).

Ripps, H.

M. M. Zaret, H. Ripps, I. M. Siegel, G. M. Breinin, Arch. Ophthalmol. 69, 97 (1963).
[CrossRef]

M. M. Zaret, G. M. Breinin, H. Schmidt, H. Ripps, I. M. Siegel, L. R. Solon, Science 134, 1525 (1961).
[CrossRef] [PubMed]

Rittler, M. C.

C. J. Campbell, M. C. Rittler, C. J. Koester, Trans. Am. Acad. Ophthalmol. Otolaryngol. 67, 58 (1963).

C. J. Koester, E. Snitzer, C. J. Campbell, M. C. Rittler, J. Opt. Soc. Am. 52, 607 (1962).

Ruffin, R. S.

W. T. Ham, R. C. Williams, W. J. Geeraets, R. S. Ruffin, H. A. Mueller, Acta Ophthalmol. (Suppl.) 76, 60 (1963).

Schmidt, H.

M. M. Zaret, G. M. Breinin, H. Schmidt, H. Ripps, I. M. Siegel, L. R. Solon, Science 134, 1525 (1961).
[CrossRef] [PubMed]

Siegel, I. M.

M. M. Zaret, H. Ripps, I. M. Siegel, G. M. Breinin, Arch. Ophthalmol. 69, 97 (1963).
[CrossRef]

M. M. Zaret, G. M. Breinin, H. Schmidt, H. Ripps, I. M. Siegel, L. R. Solon, Science 134, 1525 (1961).
[CrossRef] [PubMed]

Silbertrust, N.

N. S. Kapany, N. Silbertrust, N. A. Peppers, Appl. Opt. 4, 517 (1965).
[CrossRef]

H. C. Zweng, M. Flocks, N. S. Kapany, N. Silbertrust, N. A. Peppers, Am. J. Ophthalmol. 58, 353 (1964).

Skovberg, F.

F. Skovberg, A. V. Nielson, J. S. Krull, Scand. J. Clin. Lab. Invest. 21, 83 (1968).
[CrossRef]

Snitzer, E.

C. J. Koester, E. Snitzer, C. J. Campbell, M. C. Rittler, J. Opt. Soc. Am. 52, 607 (1962).

Solon, L. R.

M. M. Zaret, G. M. Breinin, H. Schmidt, H. Ripps, I. M. Siegel, L. R. Solon, Science 134, 1525 (1961).
[CrossRef] [PubMed]

Standl, E.

J. Ditzel, E. Standl, Acta Med. Scand. 578 (Suppl.), 59 (1975).

Staub, N. C.

N. C. Staub, Circ. Res. 43, 143 (1978).
[CrossRef] [PubMed]

Williams, R. C.

W. T. Ham, R. C. Williams, W. J. Geeraets, R. S. Ruffin, H. A. Mueller, Acta Ophthalmol. (Suppl.) 76, 60 (1963).

Wise, G. N.

G. N. Wise, Trans. Am. Ophthalmol. Soc. 54, 729 (1956).

Wolbarsht, M. L.

M. L. Wolbarsht, M. B. Landers, L. Rand, Invest. Ophthalmol. Vis. Sci. 71, Suppl. 224 (1978).

M. L. Wolbarsht, M. B. Landers, Fed. Proc. 37, 242 (1978).

Zaret, M. M.

M. M. Zaret, H. Ripps, I. M. Siegel, G. M. Breinin, Arch. Ophthalmol. 69, 97 (1963).
[CrossRef]

M. M. Zaret, G. M. Breinin, H. Schmidt, H. Ripps, I. M. Siegel, L. R. Solon, Science 134, 1525 (1961).
[CrossRef] [PubMed]

Zweifach, B.

H. H. Lipowsky, S. Kovalcheck, B. Zweifach, Circ. Res. 43, 738 (1978).
[CrossRef] [PubMed]

H. H. Lipowsky, B. Zweifach, Microvasc. Res. 14, 345 (1977).
[CrossRef] [PubMed]

B. Zweifach, Circ. Res. 34, 843 (1974).
[CrossRef] [PubMed]

H. Lipowsky, B. Zweifach, Microvasc. Res. 7, 73 (1974).
[CrossRef] [PubMed]

Zweng, H. C.

H. C. Zweng, M. Flocks, N. S. Kapany, N. Silbertrust, N. A. Peppers, Am. J. Ophthalmol. 58, 353 (1964).

M. Flocks, H. C. Zweng, Arch. Ophthalmol. 72, 604 (1964).
[CrossRef]

N. S. Kapany, N. A. Peppers, H. C. Zweng, M. Flocks, Nature 199, 146 (1963).
[CrossRef]

Acta Med. Scand.

J. Ditzel, E. Standl, Acta Med. Scand. 578 (Suppl.), 59 (1975).

E. M. Kohner, Acta Med. Scand. 578 (Suppl.), 41 (1975).

Acta Ophthalmol. (Suppl.)

W. T. Ham, R. C. Williams, W. J. Geeraets, R. S. Ruffin, H. A. Mueller, Acta Ophthalmol. (Suppl.) 76, 60 (1963).

Am. Acad. Ophthalmol. Otolaryngol.

A. Patz, S. Brem, D. Finkelstein et al., Am. Acad. Ophthalmol. Otolaryngol. 85, 626 (1978).

Am. J. Ophthalmol.

H. C. Zweng, M. Flocks, N. S. Kapany, N. Silbertrust, N. A. Peppers, Am. J. Ophthalmol. 58, 353 (1964).

Diabetic Retinopathy Study Research Group, Am. J. Ophthalmol. 81, 1 (1976).
[PubMed]

J. T. Ernest, A. M. Potts, Am. J. Ophthalmol. 72, 435 (1971).

Appl. Opt.

Arch. Ophthalmol.

M. Flocks, H. C. Zweng, Arch. Ophthalmol. 72, 604 (1964).
[CrossRef]

M. M. Zaret, H. Ripps, I. M. Siegel, G. M. Breinin, Arch. Ophthalmol. 69, 97 (1963).
[CrossRef]

F. A. L’Esperance, Arch. Ophthalmol. 74, 752 (1965).
[CrossRef]

F. A. L’Esperance, Arch. Ophthalmol. 75, 61 (1966).
[CrossRef]

Br. Med. Bull.

N. Ashton, Br. Med. Bull. 26, 103 (1970).
[PubMed]

Circ. Res.

N. C. Staub, Circ. Res. 43, 143 (1978).
[CrossRef] [PubMed]

B. Zweifach, Circ. Res. 34, 843 (1974).
[CrossRef] [PubMed]

H. H. Lipowsky, S. Kovalcheck, B. Zweifach, Circ. Res. 43, 738 (1978).
[CrossRef] [PubMed]

Fed. Proc.

M. L. Wolbarsht, M. B. Landers, Fed. Proc. 37, 242 (1978).

Invest. Ophthalmol. Vis. Sci.

M. L. Wolbarsht, M. B. Landers, L. Rand, Invest. Ophthalmol. Vis. Sci. 71, Suppl. 224 (1978).

J. Opt. Soc. Am.

C. J. Koester, E. Snitzer, C. J. Campbell, M. C. Rittler, J. Opt. Soc. Am. 52, 607 (1962).

Microvasc. Res.

H. H. Lipowsky, B. Zweifach, Microvasc. Res. 14, 345 (1977).
[CrossRef] [PubMed]

H. Lipowsky, B. Zweifach, Microvasc. Res. 7, 73 (1974).
[CrossRef] [PubMed]

Microvascular Res.

J. Ditzel, Microvascular Res. 8, 259 (1974).

Nature

T. H. Maiman, Nature 187, 493 (1959).
[CrossRef]

N. S. Kapany, N. A. Peppers, H. C. Zweng, M. Flocks, Nature 199, 146 (1963).
[CrossRef]

Ophthalmologica

F. Fankhauser, W. Lotmar, Ophthalmologica 175, 105 (1977).
[CrossRef] [PubMed]

Scand. J. Clin. Lab. Invest.

F. Skovberg, A. V. Nielson, J. S. Krull, Scand. J. Clin. Lab. Invest. 21, 83 (1968).
[CrossRef]

Science

M. M. Zaret, G. M. Breinin, H. Schmidt, H. Ripps, I. M. Siegel, L. R. Solon, Science 134, 1525 (1961).
[CrossRef] [PubMed]

Survey Ophthalmol.

F. Ederer, R. Hiller, Survey Ophthalmol. 19, 267 (1975).

A. Patz, Survey Ophthalmol. 12, 1 (1969).

Trans. Am. Acad. Ophthalmol. Otolaryngol.

C. J. Campbell, M. C. Rittler, C. J. Koester, Trans. Am. Acad. Ophthalmol. Otolaryngol. 67, 58 (1963).

Trans. Am. Ophthalmol. Soc.

F. A. L’Esperance, Trans. Am. Ophthalmol. Soc. 66, 827 (1968).

G. N. Wise, Trans. Am. Ophthalmol. Soc. 54, 729 (1956).

Trans. Ophthalmol. Soc. UK

I. C. Michaelson, Trans. Ophthalmol. Soc. UK 68, 137 (1948).

G. Meyer-Schwickerath, Trans. Ophthalmol. Soc. UK 84, 67 (1964).

Other

T. Kuwabara, L. Aiello, in Symposium on Treatment of Diabetic Retinopathy, M. Goldberg, S. Fine, Eds. (U.S. Dept. HEW, Arlington, 1968).

G. Meyer-Schwickerath, Light Coagulation (Mosby, St. Louis, 1960).

N. Peppers, SRI International; personal communication (1977).

A. Bill, in Adler’s Physiology of the Eye, R. A. Moses, Ed. (Mosby, St. Louis, 1975), pp. 210–231.

E. Friedman, in Controversy in Ophthalmology (Saunders, Philadelphia, 1977).

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Figures (7)

Fig. 1
Fig. 1

The human eye in cross section. The adult human eye is approximately 2.5 cm in diameter. The sclera is a fairly tough fibrous outer coat which assists in keeping the eye roughly spherical in shape. The retina is held against the periphery of the eye mostly by internal pressure. The major refraction of the incoming light occurs at the corneal–air interface; a lesser amount is done by the lens which changes its shape to provide focusing of far and near objects. The retina has a dual vascular bed with some vessels lying within the retina and the rest in the adjacent choroid. The retinal blood vessels enter through the optic nerve and spread out just under the inner surface of the retina to form the retinal and choroidal vascular beds. As shown in Fig. 3 the retinal vessels are greatly diminished in the macular part of the retina and are entirely absent in the fovea (the pit in the center of the macula) and in the ora serrata.

Fig. 2
Fig. 2

Cross section of the retina, choroid, and sclera. The retina is quite transparent. In the peripheral retina laser radiation is absorbed only in the retinal vessels (where present), the photopigments in the rods and cones (approximately 5%), and in the pigment granules of the pigment epithelium (approximately 50%). The pigment granules scattered throughout the choroid absorb the majority of any light not absorbed in the retina. The retinal vessels are small and widely spaced. The choroidal vessels are mostly large and give a spongy appearance to the choroid, which is otherwise largely connective tissue. There is much more blood in the choroid than in the retina, as indicated by the relative sizes of the vessels. Laser exposures produce derangement of the pigment epithelium and destruction of the adjacent rods and cones. As the injury is repaired the gap in the receptor layer is filled by the migration of adjacent rods and cones, new ones are not formed.39 The net result of pan-retinal photocoagulation is thinning of the over-all receptor density.

Fig. 3
Fig. 3

Cross section of the fovea and ora serrata. These are essentially blood-free regions of the retina that are not dependent upon the retinal circulation. Their oxygen needs are supplied by diffusion from the choroidal circulation. These regions are approximately one-half of the thickness of other parts of the retina and are representative of the area supplied by the choroidal circulation only. The fovea, shown in the upper drawing, is the pit in the retina near the optical axis of the eye. The portion of the retina containing retinal vessels (RV) is shrunken down in the fovea. The outer plexiform layer (ONL) is the fiber layer of the rods and cones, the photoreceptor cells whose cell bodies and outer segments lie in layer PR. The pigment epithelium (PE) separates the retina from the choroid (CCV). The large vessels in the choriocapillaris, the portion of the choroid nearest the retina, are large and close together. The ora serrata (lower drawing) is at the periphery of the retina (R). The usual retinal structure has disappeared, and as the retina thins the retinal vessels also disappear. The choroid (CCV) does not change its structure, and the large and frequent vessels are retained.

Fig. 4
Fig. 4

Absorption spectrum of blood and of melanin granules. Both oxygenated (HbO2) and reduced (Hb) blood absorb poorly at the 694.3-nm emission line of the ruby laser; however, the peak absorption of blood in the blue is not far from the major emission wavelengths of the argon laser used in photocoagulation. The specific absorption of melanin (M) is sufficiently high so that a thick layer of granules does not follow Beer’s law, and even the thin layer of granules in the pigment epithelium absorbs approximately 50% of the incident radiation. At longer wavelengths the absorption decreases slightly due to the size of the granules (0.5–1 μm in diameter).

Fig. 5
Fig. 5

Optical scheme for the handpiece of a ruby laser photocoagulator with a direct ophthalmoscope viewing and delivery system (Optics Technology). The operator looks through a hole in a mirror (PM) into the patient’s eye. The laser beam is generated in an optical cavity within the ophthalmoscope handpiece by the flashlamps (FL) pumping the ruby crystal (RX). The eye is illuminated by a lamp (IS) which projects a reticle (CH) along the path of the laser beam by mirrors (M, DM, M2). The distances between the patient’s eye and the physician’s (observer) eye are greatly exaggerated. In reality the physician’s eye is closely approximated to the top surface of the ophthalmoscope, while the patient’s eye is very close to the under surface. The position of the laser beam on the patient’s retina is controlled by moving the hand-held ophthalmoscope with the patient generally reclining (based on Ref. 7).

Fig. 6
Fig. 6

Optical scheme for an argon laser photocoagulator with biomicroscope delivery system (Coherent Radiation). The laser beam is brought into the biomicroscope through an articulated arm with reflecting prisms at the joints. The entire delivery system after the articulated arm consists of a modified Zeiss photoslit lamp. The physician looks through the eyepiece of a biomicroscope (with variable magnification) into the patient’s eye in the position shown. When the relative position of the biomicroscope and the patient’s eye are fixed, the exposure site of the laser beam can be moved around on the patient’s retina by a beam manipulator. The patient sits upright with his head supported by chin and forehead rests.

Fig. 7
Fig. 7

Comparison of zones in the retina supplied with oxygen by the choroidal and retinal blood vessels. The cross-hatched lines indicate the zone of overlap. The retinal and choroidal vessels each supply about half of the thickness of the retina, which is approximately at the level of the outer plexiform layer (INL), the fiber layer at the base of the rods and cones. The rods and cones utilize the majority of the oxygen supplied to the retina. They contain almost 90% of the mitochondria, the chief cellular organelles that incorporate oxygen into the metabolism. The pigment epithelium (PE) marks the junction between the retina and the choroid. (A) shows the normal zone of overlap; (B) depicts an increase of choroidal oxygen level by dissolving more oxygen in the blood plasma. (The hemoglobin is fully saturated in normal conditions.) As explained in the text the choroidal circulation does not diminish. The retinal circulation, however, is diminished in an attempt to maintain constant oxygen availability to the adjacent layers of the retina. Thus more oxygen comes into the retina from the choroidal blood, and as the blood flow in the retinal circulation is decreased the zone of overlap is pushed higher in the retina. (C) shows the oxygen supply to the retina following a laser lesion in the pigment epithelium. As the rods and cones atrophy the large amount of oxygen that they formerly consumed is now free to diffuse into the inner layers of the retina, usually supplied by the retinal circulation. The resulting constriction of the retinal vessels indicates a lowered flow in the region of the laser lesion. The laser lesion thus mimics in one region of the retina the effect of higher choroidal blood oxygenation on the whole retina.

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