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Dynamic range and stray light

An estimate of the falsifying effects of stray light in perimetry

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Abstract

The role of intraocular stray light upon contrast threshold of two skilled human observers was studied by perimetric methods using the automatic perimeter Octopus. Stray light falsifies the contrast sensitivity profile of the blind spot when a critical test stimulus luminance, which differs for various targets, is exceeded. At still higher luminance levels, because stray light effects increase, the blind spot shrinks and finally disappears. A series of high resolution measurements of the blind spot with the automatic perimeter Octopus provide a quantitative answer concerning the commencement and amount of this disturbance as a function of target size and target luminance. The amount of stray light, when using targets varying from 0 to 5 (Goldmann standard) is related to luminous power (target luminance x target area). Using first order assumptions about the stray light emitting characteristics of the disc and empirical data, one may conclude that an increase in luminance of target 0 from 103 to 105 asb only increases the effective dynamic range by about 2 dB (= 0.2 log units 3, the standard target as compared with target) size used in Octopus perimetry, at a luminance level of 103 asb. Falsification of sensitivity gradients and underestimates of depths of scotomata due to stray light effects may be an ever present danger in perimetric determinations. The useful dynamic range in perimetry appears to be limited by photon noise and noise in the neurovisual system on the one hand and by stray light interference on the other.

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Abbreviations

1 asb:

0.318 cd/m2 apostilb, luminance unit

1 dB:

0.1 log units, used in log scale for target luminances see fig, 7, T = 0/T = 5

A (deg2):

target area, measured on cupola

A1 (deg2):

area of blind spot at level L1

Au (deg2):

area of blind spot at level Lu

B (dB):

contrast sensitivity (c.s.) marking bottom of blind spot

B* (dB):

same as B, obtained from model in appendix 1

c.s. (dB):

contrast sensitivity: attenuation of threshold target luminance below 1000 asb (MAX)

DRØ (dB):

U-MAX total dynamic range

DR1 (dB):

U-B useful dynamic range including stray light interference

DR1* (dB):

U-B* same as DR1, obtained from model in appendix 1

DR2 (dB):

U-K dynamic range uncontaminated by stray light

DR2* (dB):

U-K* same as DR2, obtained from model in appendix 1

K (dB):

critical c.s. marking begin of stray light interference

L (asb):

target luminance, measured on cupola

LB (asb):

target luminance corresponding to B

Lk (asb):

critical target luminance corresponding to K

L1 (asb):

lower test level in adaptive program

LMAX (asb):

maximum target luminance of the system corresp. to MAX

LU (asb):

average target luminance corresponding to U

LU (asb):

upper test level in adaptive program

Lu (asb):

illuminance of the retina surrounding blind spot by stray light

MAX (dB):

minimum c.s. (=0 dB) corresponding to LMAX

P (erg/sec):

luminous power

R (deg):

average radius of blind spot taking stray light effects into account

R1 (deg):

average radius of blind spot at level L1

Rt (deg):

average radius of blind spot uncontaminated by stray light effects

Ru (deg):

average radius of blind spot at level Lu

S (dB):

same as c.s.

t:

tangent

T (G.S.):

target size, Goldmann standards

U (dB):

average c.s. surrounding blind spot

α:

factor, increase of background luminance

β:

factor, indicating change of Lu due to α

β':

factor, indicating change of Lx due to α in order that stray light effects remain at threshold

ΔR (deg):

reduction of radius of blind spot due to stray light interference

ΔR/Rt :

relative decrease of radius of blind spot due to stray light interference

References

  • Aulhorn, E., Harms, H. & Karmeyer, H. The influence of spontaneous eye rotation on the perimetric determination of small scotomas. Docum. Ophthal. Proc. Ser. 19: 363–367 (1979).

    Google Scholar 

  • Crick, J.C.P. & Crick, R. The sine bell stimulus in perimetry (in press).

  • Fankhauser, F. & Bebie, H. Threshold fluctuations, interpolations and spatial resolution Ophthal. 47: 89–138 (1979).

    Google Scholar 

  • Fankhauser, F. & Bebie, H. Threshold fluctuations, interpolations and spatial resolution in perimetry. Docum. Ophthal. Proc. Ser. 19: 295–309 (1979).

    Google Scholar 

  • Fankhauser, F. & Schmidt, T. Die optimalen Bedingungen für die Untersuchung der räumlichen Summation mit stehender Reizmarke nach der Methode der quantitativen Lichtsinnperimetrie. Ophthalmologica 139: 409–423 (1960).

    Google Scholar 

  • Haeberlin, H. & Fankhauser, F. Adaptive programs for the analysis of the visual field by automatic perimetry. Basic problems and solutions. Docum. Ophthal. (in press). (1980) I.

  • Haeberlin, H. & Fankhauser, F. Die Analyse parazentraler Skotome mit räumlich adaptiven Computermethoden. Klin. Mbl. Augenheilk. 176: 533–535 (1980) II.

    Google Scholar 

  • Haeberlin, H., Jenni, A. & Fankhauser, F. Researches on adaptive high resolution programming for automatic perimeter. Int. Ophthal. 2: 1–9 (1980).

    Google Scholar 

  • Jenni, A., Fankhauser, F.& Bebie, H. Neue Programme für das automatische Perimeter Octopus. Klin. Mbl. Augenheilk. 176: 536–544 (1980).

    Google Scholar 

  • Le Grand, Y. Recherches sur la diffusion de la lumière dans l'oeil humain. Rev. Optique 16: 201–240 (1937).

    Google Scholar 

  • Lyot, M.B. Etude de la couronne solaire en dehors des éclipses. Z. Astrophys. 5: 73–95 (1932).

    Google Scholar 

  • Lyot, M.B. A study of the solar corona and prominences without eclipses. Mont. Not. Roy. Astr. Soc. 99: 579–599 (1939).

    Google Scholar 

  • Miller, D. & Benedek, G. Intraocular light scattering. Springfield, Thomas, 1973.

    Google Scholar 

  • Niesel, P., Ramel, Ch. & Weidmann, B.O.S. Das Verhalten von perimetrischen Untersuchungsbefunden bei Entwicklung einer Katarakt. Klin. Mbl. Augenheilk. 172: 477–480 (1978).

    Google Scholar 

  • Rose, A. Vision. Human and electronic. New York, Plenum Press, 1977.

    Google Scholar 

  • Schoessler, J.P. The influence of visual field testing procedure on blind spot size. J. Amer, Optom. Ass. 47: 898–902 (1976).

    Google Scholar 

  • Spahr, J. Optimization of the presentation pattern in automated static perimetry. Vision Res. 15: 1275–1281 (1975).

    Google Scholar 

  • Vos, J.J. On mechanisms of glare. Soesterberg. Institute of Perception RVO-TNO. 1962.

  • Weale, R.A. & Wheeler, C. A note on stray light in the Tübingen perimeter. Brit. J. Ophthal. 61: 133–134 (1977).

    Google Scholar 

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Author notes

  1. F. Fankhauser

    Present address: Universitäts-Augenklinik, 3010, Bern, Switzerland

Authors and Affiliations

  1. Bern, Switzerland

    F. Fankhauser & H. Haeberlin

Authors
  1. F. Fankhauser
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  2. H. Haeberlin
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Fankhauser, F., Haeberlin, H. Dynamic range and stray light. Doc Ophthalmol 50, 143–167 (1980). https://doi.org/10.1007/BF00161159

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