Causes of blindness and visual impairment in a population of older Americans -: The Salisbury Eye Evaluation Study

Objective: To determine the causes of blindness and visual impairment in a population-based sample of older Americans. Methods: A random sample of 3821 residents of Salisbury Md, between the ages of 65 and 84 years was identified from Medicare records. Sixty-six percent (2520 persons) agreed to undergo an eye examination; 26% of the participants were African American. The clinical examination included acuity testing with an Early Treatment Diabetic Retinopathy Study chart and standardized refraction testing for those with a visual acuity worse than 20/30, slitlamp and dilated retinal examination by an ophthalmologist, tonometry, lens and fundus photography, and a suprathreshold visual field test. Visual impairment was defined as a best-corrected acuity in the better-seeing eye worse than 20/40 and better than 20/200, while blindness was acuity in the better-seeing eye of 20/200 or worse. For those with a visual acuity worse than 20/40 in either eye, one or more causes were assigned by an ophthalmologist and a final cause for each eye was confirmed by a panel of 3 subspecialty ophthalmologists (O.D.S., H.A.Q., and S.B.B.) based on all available evidence. Results: Bilateral presenting acuity worse than 20/40 increased from 4% in the 65- to 74-year age group to 16% in the 80- to 84-year age group. One third of those with presenting acuity worse than 20/40 improved to 20/40 or better with refraction. Overall, 4.5% had a best-corrected acuity worse than 20/40. African Americans were more likely to remain visually impaired than were whites despite refraction (odds ratio [95% confidence interval], 1.7 [1.1-2.6]). Whites were most often impaired or blind from age-related macular degeneration (1.2% vs 0.5%, P=.09). African Americans had higher rates of impairment and blindness from cataract or posterior capsular opacification (2.7% vs 1.1%; P=.006), glaucoma (0.9% vs 0.1%; P=.006), and diabetic retinopathy (1.2% vs 0.2%; P=.004). Conclusions: More than half of those with visual impairment or blindness had conditions that were either surgically treatable or potentially preventable. African Americans had a disproportionate number of blinding diseases, particularly those amenable to eye care intervention. Targeted interventions for specific populations to increase appropriate eye care use would greatly improve vision and function in older Americans.