Age-related changes in functional visual acuity in healthy individuals

Objectives: To investigate the age-related alterations in functional visual acuity (FVA) in healthy individuals. Design: A prospective non-comparative multi-center study. Setting and participants: Fifty-four eyes of 54 normal subjects with best corrected visual acuities better than 20/20 seen at the outpatient clinics of the Department of Ophthalmology at Keio University, Minamiaoyama Eye Clinic and Ishida Eye Clinic were studied. Measurements: FVA measurements, Schirmer test, BUT, tear clearance rate and fluorescein vital staining scores were obtained. Results: Schirmer test scores, BUT values and fluorescein vital staining scores did not show significant changes (p > 0.05), but there were significant differences in tear clearance rates among the age groups (p < 0.05). Tear function index, which is a value obtained from multiplying a Schirmer test score by the tear clearance rate, also showed significant differences in the age groups (p < 0.05). The mean logMAR FVA score decreased significantly in the older groups (p < 0.05), while the mean conventional VA score did not show significant differences among the age groups. Moreover, there were significantly more eyes with lower minimum VA scores in the older age groups (p < 0.05). LogMAR minimum VA appeared to be significantly related to the tear clearance rates in subjects 60 years and older (p < 0.05). Conclusions: FVA testing seems to be a useful method of assessing the age-related decline in dynamic visual and tear functions.