Functional visual acuity in dry eye disease

Dry eye disease (DED) often leads to visual disturbances despite good visual acuity on standard vision testing. Symptoms mainly occur when reading, working on a computer and/or driving a car. The inferior optical quality of the ocular surface in DED seems to be responsible for these symptoms, with an increase of topometric irregularity and asymmetry, rise in irregular astigmatism, increase in corneal and ocular higher order aberrations, decrease in contrast sensitivity and increase in light scattering. Functional visual acuity represents the visual function over time and reflects the visual performance of an individual during daily activities. It is significantly reduced in DED compared to controls. A number of tests have been reported for evaluation of functional visual acuity. No single method has so far become established in the daily clinical practice.