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Visual Acuity Changes in Population Over a 15-Year Period PDF
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Ophthalmology and Optometry
Monday, 13 November 2006
Researchers at the University of Wisconsin School of Medicine and Public Health in U.S. conducted a population-based study based on the Beaver Dam Study in an effort to describe changes in visual acuity in a population over a 15-year period.

The participants included 4,068 people aged 43 to 86 years at the time of a baseline examination between 1988 to 1990 who had follow-up examinations every five years thereafter. Observation procedures included best-corrected visual acuity after refraction, assessed by a modification of the ETDRS protocol. The main outcome measures were doubling of the visual angle and incidence of visual impairment.

Eight percent of the population developed impaired vision (20/40 or worse), 0.8 percent developed severe visual impairment (20/200 or worse), 7 percent had doubling of the visual angle and 2 percent had improved vision after 15 years. People who were 75 years or older at baseline were more likely to develop impaired vision, doubling of the visual angle, and severe visual impairment compared with people younger than 75 years at baseline. In those who were 75 years of age or older at baseline, the cumulative incidence of visual impairment accounting for the competing risk of death was 25 percent, of which 4 percent was severe.

The authors believe this indicates a public health problem of considerable proportions, because the U.S. population of this age group is expected to increase by 55 percent, from 18 million in the year 2005 to 28 million by the year 2025.