Treating visual disorders in the elderly might delay the onset of late-life dementia—particularly Alzheimer’s disease, Medicare and study data for 625 elderly patients show.
Those participants who had at least one visit with an ophthalmologist were 64% less likely to develop dementia during 10 years of follow-up than those who did not visit an ophthalmologist, Mary A.M. Rogers, Ph.D., and Dr. Kenneth M. Langa of the University of Michigan, Ann Arbor, reported online in the Feb. 11 issue of the American Journal of Epidemiology.
Study participants were individuals over age 50 years from the nationally representative Health and Retirement Study who had normal cognition at baseline and were followed for a mean of 10 years. Visual health practices and outcomes and cognitive health outcomes were evaluated using linked data from the study and from the files of the U.S. government-sponsored medical coverage agency, the Centers for Medicare and Medicaid Services.
Of the 625 participants, 168 developed dementia, 169 were diagnosed as cognitively impaired but no dementia (CIND), and 288 maintained normal cognition during follow-up, Dr. Rogers and Dr. Langa reported.
Only about 10% of those who developed dementia had excellent vision at baseline, compared with nearly 31% of those who maintained normal cognition, the investigators found (Am. J. Epidemiol. 2010 [doi: 10.1093/aje/kwp453]).
The investigators also looked at the relationship between eye care and dementia, and found a significant association between prior eye care services and dementia, with a 56% reduction in the risk of dementia in those who had an eye procedure, compared with those who had no procedure.
The risk of nonvascular dementia was decreased by 10% for each visit to an ophthalmologist, 18% for each eye procedure, and 7% for each eye-related diagnosis. Findings were similar when analysis was restricted to those followed for at least 6 years prior to the outcome, and when restricted to those who did not have vascular disease.
In participants who were aged 90 years or older and who developed Alzheimer’s disease during the study, only 52% received at least one prior eye procedure, compared with nearly 78% of those who maintained normal cognition, the investigators found.
The findings suggest that treatment in those with poor vision does affect dementia-related outcomes, they noted.
Participants with poor vision who did not visit an ophthalmologist had a ninefold increased risk of Alzheimer’s disease and a fivefold increased risk of CIND, but the risk of cognitive decline was not significantly increased in those with poor vision who did visit an ophthalmologist.
Furthermore, the risk of Alzheimer’s disease was increased to a greater degree in those with poor vision and no prior eye procedure, than in those with poor vision who had a prior eye procedure (relative risk ratios of 5.35 vs. 2.52, respectively).
Again, the findings were similar when the analyses were restricted to those followed at least 6 years prior to the outcome.
Links between visual disturbances and cognitive impairment are well documented in both the ophthalmologic and psychiatric literature. But prior studies have not determined whether the eye pathologies are precursors or consequences of cognitive decline, the investigators noted.
The findings of this study suggest there is not only a link between impaired vision and Alzheimer’s disease, but that treating visual problems affects the probability of developing Alzheimer’s disease, they said, concluding that “it is possible that underdiagnosis or undertreatment of visual problems in the elderly may contribute to cognitive decline.”
The possibility that treatment of visual disorders in this population can alleviate cognitive decline deserves further study, they argued, noting that the current study is limited by its observational nature and the lack of specific testing for vision at uniform intervals prior to diagnosis of dementia or CIND.
The investigators also encouraged continued consideration of including vision testing within comprehensive consultations for preventing dementia in the elderly, and they encouraged investigation of the cost-effectiveness of providing government-sponsored medical coverage (Medicare) for vision screening to postpone cognitive decline later in life.
This study, as well as the Health and Retirement Study, received funding from the U.S. National Institute on Aging. The investigators declared no conflicts of interest.
