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 age s of 65 and 84 years was identified from Medicare records. Sixty-six percen t (2520 persons) agreed to undergo an eye examination; 26% of the participa nts 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, slitlam p and dilated retinal examination by an ophthalmologist, tonometry, lens an d fundus photography, and a suprathreshold visual field test. Visual impair ment 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 2 0/40 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 o phthalmologists (O.D.S., H.A.Q., and S.B.B.) based on all available evidenc e. 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 th ird of those with presenting acuity worse than 20/40 improved to 20/40 or b etter 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 macul ar degeneration (1.2% vs 0.5%, P=.09). African Americans had higher rates o f impairment and blindness from cataract or posterior capsular opacificatio n (2.7% vs 1.1%; P=.006), glaucoma (0.9% vs 0.1%; P=.006), and diabetic ret inopathy (1.2% vs 0.2%; P=.004). Conclusions: More than half of those with visual impairment or blindness ha d conditions that were either surgically treatable or potentially preventab le. African Americans had a disproportionate number of blinding diseases, p articularly those amenable to eye care intervention. Targeted interventions for specific populations to increase appropriate eye care use would greatl y improve vision and function in older Americans.