Effect of short wavelength filters on visual function in simulated cataract

The aim of this study was to determine the effects of Corning Photochromic Filters (CPF) on visual function for healthy subjects with simulated cataract. Fifty-five subjects were recruited with a mean (± S.D.) age of 24 ± 2.34 years. High contrast (90%) distance visual acuity was measured with a Bailey-Lovie log MAR chart, contrast threshold with a Pelli-Robson chart (assessments were made with and without glare) and the MNRead chart was used to determine threshold reading acuity and critical print size. Three CPFs (450, 511 and 527) were used and cataracts were simulated with frosted lenses. Subjects were also tested with frosted lens and no CPF. ANOVA indicated significant differences (p < 0.001) between the overall effect of glare and between CPFs for high contrast distance visual acuity and contrast threshold. A gradual decline in visual performance was noted for increasing CPF absorption. Threshold reading acuity and critical print size were compared for each CPF and statistically significant relationships between CPF450 and CPF527 and also between cataract simulation and CPF527 (p < 0.001) were found. Our results showed statistical significance between CPFs in all tests of visual function. In our opinion, although the results indicate statistical significance, they bear little clinical significance.