Abstract

The visual threshold of the fovea is raised by a surrounding ‘glare’ ring of bright light. If this is due entirely to scattered light, then the equivalent uniform background that raises the threshold equally will bleach the cone pigments equally. The equivalence of bleaching was measured by two different techniques: retinal densitometry, and the effect on subsequent dark adaptation. Both agree that the background which matches the glare in raising the threshold for foveal cones also matches it (correct to 0.1 log unit) in bleaching the pigment in those same cones.

© 1966 Optical Society of America

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References

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  1. J. J. Vos, “On Mechanism of Glare,” thesis, Utrecht (1963).
  2. L. L. Holladay, J. Opt. Soc. Am. 12, 271 (1926).
    [Crossref]
  3. L. L. Holladay, J. Opt. Soc. Am. 14, 1 (1927).
    [Crossref]
  4. W. S. Stiles, Proc. Roy. Soc. (London) B104, 322 (1929).
  5. Y. LeGrand, Rev. Opt. 16, 201, 241 (1937).
  6. R. M. Boynton, J. M. Enoch, and W. R. Bush, J. Opt. Soc. Am. 44, 879 (1954).
    [Crossref] [PubMed]
  7. H. B. Barlow, J. Physiol. (London) 119, 69 (1953).
  8. K. O. Donner, J. Physiol. (London) 149, 318 (1959).
  9. W. S. Stiles and B. H. Crawford, Proc. Roy. Soc. (London) B122, 255 (1937).
  10. W. A. H. Rushton, J. Physiol. (London) 168, 345 (1963).
  11. W. A. H. Rushton, J. Physiol. (London) 176, 24 (1965).
  12. H. D. Baker and W. A. H. Rushton, J. Physiol. (London) 176, 56 (1965).
  13. W. A. H. Rushton, Ann. N. Y. Acad. Sci. 74, 291 (1958).
    [Crossref]
  14. J. F. Schouten and L. S. Ornstein, J. Opt. Soc. Am. 29, 168 (1939).
    [Crossref]
  15. G. A. Fry and M. Alpern, J. Opt. Soc. Am. 43, 189 (1953).
    [Crossref] [PubMed]
  16. J. J. Vos, J. Opt. Soc. Am. 53, 1449 (1963).
    [Crossref] [PubMed]
  17. G. Westheimer (personal communication, 1964).
  18. W. A. H. Rushton, J. Physiol. (London) 168, 374 (1963).
  19. W. A. H. Rushton, J. Physiol. (London) 176, 38 (1965).

1965 (3)

W. A. H. Rushton, J. Physiol. (London) 176, 24 (1965).

H. D. Baker and W. A. H. Rushton, J. Physiol. (London) 176, 56 (1965).

W. A. H. Rushton, J. Physiol. (London) 176, 38 (1965).

1963 (3)

W. A. H. Rushton, J. Physiol. (London) 168, 345 (1963).

J. J. Vos, J. Opt. Soc. Am. 53, 1449 (1963).
[Crossref] [PubMed]

W. A. H. Rushton, J. Physiol. (London) 168, 374 (1963).

1959 (1)

K. O. Donner, J. Physiol. (London) 149, 318 (1959).

1958 (1)

W. A. H. Rushton, Ann. N. Y. Acad. Sci. 74, 291 (1958).
[Crossref]

1954 (1)

1953 (2)

H. B. Barlow, J. Physiol. (London) 119, 69 (1953).

G. A. Fry and M. Alpern, J. Opt. Soc. Am. 43, 189 (1953).
[Crossref] [PubMed]

1939 (1)

1937 (2)

W. S. Stiles and B. H. Crawford, Proc. Roy. Soc. (London) B122, 255 (1937).

Y. LeGrand, Rev. Opt. 16, 201, 241 (1937).

1929 (1)

W. S. Stiles, Proc. Roy. Soc. (London) B104, 322 (1929).

1927 (1)

1926 (1)

Alpern, M.

Baker, H. D.

H. D. Baker and W. A. H. Rushton, J. Physiol. (London) 176, 56 (1965).

Barlow, H. B.

H. B. Barlow, J. Physiol. (London) 119, 69 (1953).

Boynton, R. M.

Bush, W. R.

Crawford, B. H.

W. S. Stiles and B. H. Crawford, Proc. Roy. Soc. (London) B122, 255 (1937).

Donner, K. O.

K. O. Donner, J. Physiol. (London) 149, 318 (1959).

Enoch, J. M.

Fry, G. A.

Holladay, L. L.

LeGrand, Y.

Y. LeGrand, Rev. Opt. 16, 201, 241 (1937).

Ornstein, L. S.

Rushton, W. A. H.

W. A. H. Rushton, J. Physiol. (London) 176, 24 (1965).

W. A. H. Rushton, J. Physiol. (London) 176, 38 (1965).

H. D. Baker and W. A. H. Rushton, J. Physiol. (London) 176, 56 (1965).

W. A. H. Rushton, J. Physiol. (London) 168, 345 (1963).

W. A. H. Rushton, J. Physiol. (London) 168, 374 (1963).

W. A. H. Rushton, Ann. N. Y. Acad. Sci. 74, 291 (1958).
[Crossref]

Schouten, J. F.

Stiles, W. S.

W. S. Stiles and B. H. Crawford, Proc. Roy. Soc. (London) B122, 255 (1937).

W. S. Stiles, Proc. Roy. Soc. (London) B104, 322 (1929).

Vos, J. J.

J. J. Vos, J. Opt. Soc. Am. 53, 1449 (1963).
[Crossref] [PubMed]

J. J. Vos, “On Mechanism of Glare,” thesis, Utrecht (1963).

Westheimer, G.

G. Westheimer (personal communication, 1964).

Ann. N. Y. Acad. Sci. (1)

W. A. H. Rushton, Ann. N. Y. Acad. Sci. 74, 291 (1958).
[Crossref]

J. Opt. Soc. Am. (6)

J. Physiol. (London) (7)

H. B. Barlow, J. Physiol. (London) 119, 69 (1953).

K. O. Donner, J. Physiol. (London) 149, 318 (1959).

W. A. H. Rushton, J. Physiol. (London) 168, 345 (1963).

W. A. H. Rushton, J. Physiol. (London) 176, 24 (1965).

H. D. Baker and W. A. H. Rushton, J. Physiol. (London) 176, 56 (1965).

W. A. H. Rushton, J. Physiol. (London) 168, 374 (1963).

W. A. H. Rushton, J. Physiol. (London) 176, 38 (1965).

Proc. Roy. Soc. (London) (2)

W. S. Stiles and B. H. Crawford, Proc. Roy. Soc. (London) B122, 255 (1937).

W. S. Stiles, Proc. Roy. Soc. (London) B104, 322 (1929).

Rev. Opt. (1)

Y. LeGrand, Rev. Opt. 16, 201, 241 (1937).

Other (2)

G. Westheimer (personal communication, 1964).

J. J. Vos, “On Mechanism of Glare,” thesis, Utrecht (1963).

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Figures (6)

Fig. 1
Fig. 1

(A) Annular glare presentation. Measuring light falls on central 3° diameter circle; phototube observes central 2°. (B) Sector-like rotating mirrors (stippled) which alternate bleaching and measuring lights. The two crescents attached to the mirrors intercept the axis a and provide the dark periods between bleaching and measuring lights. (C) Cross section of rotating mirror device. Measuring light travels along axis aa; bleaching light follows bb but is reflected at mirror along aa.

Fig. 2
Fig. 2

Time cycle of lights and shutter positions during glare experiment. During tests involving an equivalent uniform background, black central patch remains out of view. (a) phases of bleaching and measuring lights, (b) lines show when the photocell was screened, (c) positions of black center.

Fig. 3
Fig. 3

Fraction of visual pigment p remaining on the fovea as a function of equilibrium illumination in log trolands. One half the pigment remains at 3.9 log trolands.

Fig. 4
Fig. 4

Time course of bleaching under conditions of periodically varying illumination. Curve A—variation of pigment fraction p under 4.5 log td uniform field (open circles), and 5.7 log td annular glare field (triangles). Curve B—variation of p under 5.7 log td glare source (triangles), 3.8 log td uniform field (filled circles), and 4.1 log td uniform field (open circles). Scale for curve B is at right.

Fig. 5
Fig. 5

Log increment threshold as a function of log background luminance for the glare presentation of Fig. 1(A) (filled symbols), and for a uniform background attenuated 1.7 log units below the glare luminance (open symbols). Circles result from a red test flash and triangles from a green test flash.

Fig. 6
Fig. 6

The square wave on the time axis represents the course of bleaching, 10 sec on 10 sec off for 6 exposures. During the dark gap the foveal threshold was measured and log threshold at the end of each gap is plotted. Open circles, uniform bleaching field of 3.8 log td; filled circles, the same at 3.5 log td; triangles when bleaching was from the annular glare of 5.7 log td. Squares show similar measurements when the test flash fell upon the parafoveal area that was illuminated by glare directly (log threshold scale on right). Curves A, B, and C have the time course calculated from Eq. (3).

Tables (1)

Tables Icon

Table I The bleaching by glare scatter and equivalent backgrounds.

Equations (3)

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Δ I = A + C 1 I 1 ,
Δ I = A + C 2 I 2 ,
- t 0 d p / d t = ( p I / I 0 ) - ( 1 - p ) ,