Effects of color filters and anti-reflective coating on contrast sensitivity under glare condition

Abstract

Background: Since light scattering has a great impact on visual performances, this study was conducted to compare the effects of color filters and anti-reflective coating on contrast sensitivity (CS) in normal people under glare condition. Methods: This semi-experimental study was conducted on 40 medical students (aged 19- 25 years). Ophthalmologic tests including visual acuity and refractive error measurement, biomicroscopy, fundoscopy, and CS assessment were conducted for all participants. CS was determined using Pelli-Robson chart at a distance of one meter. To measure the effect of glare on CS, we used an additional lighting source (60 W tungsten filament incandescent lamp) in the patient’s visual field. Thus, at an intensity of 2000 lux, the light source was placed at a distance of 18.5 cm from the patient’s eye in a way that it was 10 degrees above the subject’s visual axis. Monocular CS measurements were performed with and without glare. Monocular CS was evaluated again under glare conditions with the yellow and pink filters, with the transmission rate of 85%, and anti-reflective coating. Results: The mean log CS of subjects under glare (1.48±0.09) was lower than that in the absence of glare (1.71±0.09) (<0.001); moreover, repeated measures ANOVA showed the yellow filter (1.48±0.10), pink filter (1.47±0.10), and anti-reflective coating (1.47±0.09) had no significant impact on improving visual performance under glare condition (P=0.471). Conclusion: Colored filters and anti-reflective coatings are not effective in enhancing the vision of young normal individuals under glare conditions and at low spatial frequencies.