Optical aberrations and visual disturbances associated with dry eye

Optical aberrations and visual disturbances are associated with dry eye, although visual impairment is often not detected by conventional visual acuity testing. The newly developed functional visual acuity (FVA) device allows continuous dynamic evaluation of distance visual acuity and assessment of the effect of natural tear film status on dynamic visual function. Similarly, to detect corneal surface irregularities during sustained eye opening in dry eye subjects, a new tear stability analysis system (TSAS) has been developed. Both FVA and TSAS measurement systems seem to be effective tools in the assessment of dynamic visual acuity changes in dry eye and normal subjects. Both methods were also found to be helpful in the evaluation of the outcome of management of dry eye disease. FVA testing has been suggested to be an important indication of an individual's performance in relation to certain daily activities, such as driving, reading and working at a video display terminal. This review provides illustrations of results obtained from FVA and TSAS systems.