Effect of a polarized filter on photopic contrast sensitivity and disability glare.

Abstract

PURPOSE: To establish the effect of a solar polarized filter on photopic contrast sensitivity (CS) determined with an without glare and on disability glare. METHODS: Natural sunlight is partly polarized and polarized filters are the only way capable of bloking the glare produced by reflection. Other types of solar filters only reduce the level of luminance CS with and without glare were determined using de CGT 1000 )6 stimulus suze-6.3 to 0.7 degrees; 12 levels of contras-0.01 to 0.45; 8 peropheral glare sources) at photopic luminance level and under different conditions: without filter ( to avoid the patient learning effect) or using a graphite of polarized filter on an alternating basis. The study sample comprised of 82 subjects aged 18 to 95 (56 +-21) years. RESULTS: Differences in disability glare were recorded for intermediate stimulus sizes between both filters. Differences statiscally significants in disability glare according to the filter versus without filter were recorded for intermediate stimulus sizes. CS values for intermediate stimulus determined in the presence of glare differed significantly when comparing the use of no filter versus both filters, or between both filters with glare. CONCLUSION: The use of solar filters improves CS for intermediate stimulus sizes, being highest values using the polarized filter.