Individuals age 49 and older with cataract and those age 49 to 74 years with age-related macular degeneration appear to have higher mortality rates over an 11-year period than those without such visual impairments, according to a report in the July issue of Archives of Ophthalmology, one of the JAMA/Archives journals.
Several studies have shown associations between visual problems and the risk of death in older individuals, according to background information in the article.
?The mechanisms for higher mortality associated with visual impairment remain unclear,? the authors write. ?It could be attributed to age-related ocular conditions, such as age-related macular degeneration (ARMD) or cataract, which can be markers of biological aging. Alternatively, visual impairment and its related ocular conditions could share a similar pathogenesis with other conditions associated with increased mortality.?
Sudha Cugati, M.S., of the University of Sydney, Australia, and colleagues assessed 3,654 individuals age 49 and older who were part of the Blue Mountains Eye Study, an ongoing examination of visual disorders in the Blue Mountains area west of Sydney. When the participants enrolled in the study, between 1992 and 1994, they were assessed for overall visual impairment and its two main causes: cataract, a disease in which the eye?s lens is covered by a film that reduces sight, and ARMD, which occurs when the macula, the area at the back of the retina that produces the sharpest vision, deteriorates over time.
By Dec. 31, 2003?an average of 11 years of follow-up?1,051 participants (28.9 percent) died. Rates of death were higher among those with any visual impairment than among those without (54 percent vs. 34 percent), among those with ARMD than those without (45.8 percent vs. 33.7 percent) and among those with cataract than those without (39.2 percent vs. 29.5 percent).
?After adjusting for factors that predict mortality, neither visual impairment nor ARMD was significantly associated with all-cause mortality in all ages,? the authors write. ?Among persons younger than 75 years, however, ARMD predicted higher all-cause mortality.? Among participants of all ages, having cataract also was associated with a higher risk of death from any cause.
It remains unclear whether there is a direct or indirect link between visual impairment and death or if another factor not measured in this study affected the results, the authors note. ?The implications of these findings also remain uncertain: whether such an association indicates that visual impairment, age-related eye disease or both are markers of aging and frailty or whether these ocular conditions accelerate aging, thus leading to relatively earlier death in older persons,? they conclude. ?If a direct or indirect causal effect from visual impairment on earlier death is confirmed, regular assessment of vision in older persons may lead to early detection, facilitating treatments that could reduce the impact of visual impairment.?