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Tim Schilling, Arne Ohlendorf, Siegfried Wahl; Induced straylight decreases visual performance homogenously at different spatial frequencies measured by the Tuebingen Contrast Sensitivity Test. Invest. Ophthalmol. Vis. Sci. 2019;60(9):5902.
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© ARVO (1962-2015); The Authors (2016-present)
Increased retinal straylight, caused by e.g. cataract, can decrease the visual performance with less affecting visual acuity. Using computerized tests that measure the contrast threshold for different spatial frequencies, such tests can be used to estimate the effect of straylight on the sensitivity to contrast.The aim of this study was to investigate, how CS changes at different spatial frequencies with induced straylight by black pro mist (BPM) filter and an annular scatter source.
CS was assessed in fifteen participants with the Tuebingen Contrast Sensitivity Test with 50 trials per spatial frequency (SF) for 0.5, 1, 1.5, 2.1, 3, 4.2, 6, 8.5 and 12 cycle per degree (cpd) under the conditions with and without BPM 3 filter (Tiffen, NY, USA). The stimulus, a Gabor Patch, was surrounded by a white annulus, that served as a scatter source, in order to induce retinal straylight maximally in the field of the stimulus. A ViewPixx monitor (ViewPixx 3D, VPixx Technologies, Saint-Bruno, Canada) presented the stimuli for 300 ms on a gray background, whereas the annulus was white from the inner radius at 5° to the outer radius at 10°. The luminance of the monitor was adapted, so that behind the filter and without the filter the luminance reaching the eye was the same for both conditions. For statistical analysis a repeated ANOVA was performed.
The ANOVA returned significant main effects for the factor filter (p < 0.001), the factor SF (p < 0.001) and the interaction between filter and SF (p < 0.001). This interaction revealed that the straylight inducing filter reduced the CS function homogenously over all measured SFs. The maximum of the CS function shifted slightly from 2.1 cpd to 1.5 cpd, when comparing the conditions without and with BPM 3.
With the white annulus as scatter light source and under constant luminance conditions at the eye, the CS was homogenously reduced by a straylight inducing filter at all tested SFs. The used method to simulate a scatter light source does not need an additional external light source because it uses the light from the monitor itself.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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