Visual acuity variations under different contrast conditions in age-related macular degeneration patients using freiburg visual acuity test

Abstract

Introduction. Age-related macular degeneration (ARMD) is progressive disease of the central retina and a major cause of blindness worldwide. Visual loss from this condition is uncommon among persons under the age of 50, but its prevalence is likely to increase in absolute numbers globally as a consequence of population ageing. It is very important to use diagnostic tools that can define early or preclinical stages of the disease because if untreated it can cause blindness in late stages of the disease. One common approach in assessing retinal function is measuring visual acuity (VA). Although acuity testing is sample to implement in a clinical setting, it does not give exclusive information on retinal function in early ARMD when changes in visual acuity are minimal (two letter loss or longMAR 0.04). So testing basic aspects of vision , such as color perception, contrast sensitivity, and visual adaption, is more likely to reflect an alteration of retinal function in early ARMD. Visual acuity tests by the typical Snellen chart using the Landolt rings (C optotypes) alone is insufficient because it provides limited information about the central vision and it is difficult to evaluate in patients with macular abnormalities because the reduction in acuity shows that foveal acuity is lower than peripheral acuity. Aim. Evaluation of differences in visual acuity variations of eyes with early ARMD compared to healthy eyes under different contrast conditions using Freiburg Visual Acuity Test (FrACT). [...].