Effect of glare on contrast sensitivity function

Abstract

Purpose : Various devices are utilized to induce glare; data on these devices on contrast sensitivity function (CSF) on healthy subjects is limited. With the advent of refractive surgeries and elective cataract surgeries with multifocal intraocular lenses, it becomes important to assess the effect of glare in individuals with normal visual acuity. The purpose of the study was to evaluate the effect of induced glare on measurement of CSF under various conditions.

Methods : The study was conducted in two parts: 1) To evaluate the effect of inbuilt glare lights on CSF measured under photopic conditions 2) To evaluate the effect of induced glare at two light levels under mesopic conditions. 1) Fifty one subjects underwent CSF testing with CSV-1000E without glare and with glare with (69 lux) under photopic conditions. 2) Twenty five subjects underwent CSF testing under mesopic conditions without glare and with glare at two levels a) 69 lux and b) 228 lux. A paired samples t-test was performed to evaluate the difference in CSF measured with and without glare under photopic conditions. One-way ANOVA with contrasts was performed to evaluate the CSF with and without glare in mesopic conditions.

Results : The CSF under photopic conditions without glare was -1.95,-2.18,-1.84 & -1.39; the CSF with induced glare under photopic conditions was -1.92, -2.13, -1.84 & -1.37 for 3, 6, 12 and 18 CPD respectively. The difference in CSF was not significantly different for any spatial frequency. Comparing mesopic CSF without glare and with low and high glare we find that there is a significant decline in vision with induced glare. The contrasts indicate that CSF in mesopic condition with low glare is not significantly different compared to the mesopic condition without glare. Whereas the mesopic CSF under high glare condition was significantly different compared to the mesopic condition without glare for all spatial frequencies except 18 CPD.

Conclusions : Under mesopic conditions the light levels of 228 lux is sufficient to reduce CSF in low and mid spatial frequency.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.