Abstract
Abstract: :
Purpose: To study the incidence of blindness and low vision over a 12-year period. Methods: The survivors of the original cohort of 1,028 persons from Ponza, Italy, aged 40 years and over, were re-examined after 12 years from a base-line visit. Of the 507 eligible survivors, 411 (81.1%) had a 12-year follow-up visit. Base-line and follow-up examinations included the collection of anamnestic and ophthalmologic data by the same observers using the same methods and classification criteria. Best-corrected visual acuity measured by means of standardized logarithmic chart was expressed as the logarithm of the minimum angle of resolution (logMAR). WHO definitions of blindness and low vision were adopted. Participants at risk for visual impairment were those without blindness or low vision in the better eye at baseline; participants at risk for one eye visual impairment were those without blindness or low vision in both eyes at baseline. Results: A total of 44 participants were defined as incident cases of visual impairment. The overall incidence figures for blindness, low vision, one eye blindness, and one eye low vision were respectively 0.5% (95% CI, 0.1-1.8), 3.4% (95% CI, 2.1-5.8), 2.0% (95% CI, 1.0-3.9) and 5.0% (95% CI, 2.9-7.2).Conclusions: Our study provides population-based estimates of the incidence of visual impairment in an adult free-living population. Older subjects at baseline were at higher risk for incident visual impairment, the main causes of which resulted to be cataract, myopia, age-related macular degeneration and diabetic retinopathy. The incidence of binocular "severe impairment" in the subgroup aged 43 to 74 years at baseline was significantly higher than that found in Beaver Dam 10-year Study, when the same definitions were adopted.
Keywords: clinical (human) or epidemiologic studies: pre • clinical (human) or epidemiologic studies: hea • aging: visual performance