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The Influence of Simulated Light Scattering on Automated Perimetric Threshold Measurements

The Influence of Simulated Light Scattering on Automated Perimetric Threshold Measurements Abstract • The effect of light scattering by ocular media opacities on OCTOPUS and Humphrey perimeter threshold measurements was simulated with randomly ordered sequences of six ground-glass diffusers in the right eyes of five subjects. Threshold measurements were performed at 0°, 5°, 10°, 15°, 20°, and 25° nasally along the 180° meridian with the F4 program on an OCTOPUS perimeter, and with twice-repeated profiles on a Humphrey perimeter. The reduction in differential light sensitivity correlated well with the 2.7-dB to 16.7-dB reduction in stimulus intensity caused by the 46% to 98% scattering of incident light by the diffusers. Contrast sensitivity in the presence of a glare source (Miller-Nadler glare test) was also affected by the diffusers, such that a 75% contrast target was not visible through the strongest diffuser whereas a 5% contrast target was visible without a diffuser. Conversely, the diffusers had very little effect on visual acuity measurements that were performed with projected high-contrast targets in a darkened room. Our data suggest that even minimal light scattering, such as might be caused by a cataract that has a relatively insignificant effect on visual acuity, may influence threshold measurements. References 1. Heuer DK, Gressel MG, Anderson DR, et al: Does the OCTOPUS perimeter obey Weber's Law? Invest Ophthalmol Vis Sci 1985;26( (ARVO suppl) ):40. 2. Klewin KM, Radius RL: Background illumination and automated perimetry . Arch Ophthalmol 1986;104:395-397.Crossref 3. Sloan LL: Area and luminance of test object as variables in examination of the visual field by projection perimetry . Vision Res 1961;1:121-138.Crossref 4. Fankhauser F, Enoch JM: The effects of blur upon perimetric thresholds: A method for determining a quantitative estimate of retinal contour . Arch Ophthalmol 1962;68:240-251.Crossref 5. Benedetto MD, Cyrlin MN: The effect of blur upon static perimetric thresholds , in Heijl A, Greve EL (eds): Proceedings of the Sixth International Visual Field Symposium . Dordrecht, the Netherlands, Dr W Junk Publishers, 1985, pp 563-567. 6. Weinreb RN, Perlman JP: The effect of refractive correction on automated perimetric thresholds . Am J Ophthalmol 1986;101:706-709. 7. Heuer DK, Anderson DR, Feuer WJ, et al: The influence of refraction accuracy on automated perimetric threshold measurements . Ophthalmology 1987;94:1550-1553.Crossref 8. LeClaire J, Nadler MP, Weiss S, et al: A new glare tester for clinical testing: Results comparing normal subjects and variously corrected aphakic patients . Arch Ophthalmol 1982;100:153-158.Crossref 9. Hirsch RP, Nadler MP, Miller D: Clinical performance of a disability glare tester . Arch Ophthalmol 1984;102:1633-1636.Crossref 10. Heuer DK, Anderson DR, Feuer WJ, et al: The influence of simulated media opacities on threshold measurements , in Greve EL, Heijl A (eds): Proceedings of the Seventh International Visual Field Symposium . Dordrecht, the Netherlands, Martinus Nijhoff/Dr W Junk Publishers, 1987, pp 15-22. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Archives of Ophthalmology American Medical Association

The Influence of Simulated Light Scattering on Automated Perimetric Threshold Measurements

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Publisher
American Medical Association
Copyright
Copyright © 1988 American Medical Association. All Rights Reserved.
ISSN
0003-9950
eISSN
1538-3687
DOI
10.1001/archopht.1988.01060140407042
Publisher site
See Article on Publisher Site

Abstract

Abstract • The effect of light scattering by ocular media opacities on OCTOPUS and Humphrey perimeter threshold measurements was simulated with randomly ordered sequences of six ground-glass diffusers in the right eyes of five subjects. Threshold measurements were performed at 0°, 5°, 10°, 15°, 20°, and 25° nasally along the 180° meridian with the F4 program on an OCTOPUS perimeter, and with twice-repeated profiles on a Humphrey perimeter. The reduction in differential light sensitivity correlated well with the 2.7-dB to 16.7-dB reduction in stimulus intensity caused by the 46% to 98% scattering of incident light by the diffusers. Contrast sensitivity in the presence of a glare source (Miller-Nadler glare test) was also affected by the diffusers, such that a 75% contrast target was not visible through the strongest diffuser whereas a 5% contrast target was visible without a diffuser. Conversely, the diffusers had very little effect on visual acuity measurements that were performed with projected high-contrast targets in a darkened room. Our data suggest that even minimal light scattering, such as might be caused by a cataract that has a relatively insignificant effect on visual acuity, may influence threshold measurements. References 1. Heuer DK, Gressel MG, Anderson DR, et al: Does the OCTOPUS perimeter obey Weber's Law? Invest Ophthalmol Vis Sci 1985;26( (ARVO suppl) ):40. 2. Klewin KM, Radius RL: Background illumination and automated perimetry . Arch Ophthalmol 1986;104:395-397.Crossref 3. Sloan LL: Area and luminance of test object as variables in examination of the visual field by projection perimetry . Vision Res 1961;1:121-138.Crossref 4. Fankhauser F, Enoch JM: The effects of blur upon perimetric thresholds: A method for determining a quantitative estimate of retinal contour . Arch Ophthalmol 1962;68:240-251.Crossref 5. Benedetto MD, Cyrlin MN: The effect of blur upon static perimetric thresholds , in Heijl A, Greve EL (eds): Proceedings of the Sixth International Visual Field Symposium . Dordrecht, the Netherlands, Dr W Junk Publishers, 1985, pp 563-567. 6. Weinreb RN, Perlman JP: The effect of refractive correction on automated perimetric thresholds . Am J Ophthalmol 1986;101:706-709. 7. Heuer DK, Anderson DR, Feuer WJ, et al: The influence of refraction accuracy on automated perimetric threshold measurements . Ophthalmology 1987;94:1550-1553.Crossref 8. LeClaire J, Nadler MP, Weiss S, et al: A new glare tester for clinical testing: Results comparing normal subjects and variously corrected aphakic patients . Arch Ophthalmol 1982;100:153-158.Crossref 9. Hirsch RP, Nadler MP, Miller D: Clinical performance of a disability glare tester . Arch Ophthalmol 1984;102:1633-1636.Crossref 10. Heuer DK, Anderson DR, Feuer WJ, et al: The influence of simulated media opacities on threshold measurements , in Greve EL, Heijl A (eds): Proceedings of the Seventh International Visual Field Symposium . Dordrecht, the Netherlands, Martinus Nijhoff/Dr W Junk Publishers, 1987, pp 15-22.

Journal

Archives of OphthalmologyAmerican Medical Association

Published: Sep 1, 1988

References