Visual Impairment Associated With Increased Mortality Risk

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 journals1.

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.”

A related article in the same edition of the journal reports that many nursing home residents may not receive regular eye examinations.

In a study of Alabama nursing home residents, more than half were visually impaired yet two-thirds had no record of or reference to an eye examination in their medical charts, according to a report in the July issue of Archives of Ophthalmology, one of the JAMA/Archives journals2.

Previous studies have estimated that nursing home residents have visual impairment rates anywhere from three to 15 times higher than adults of the same age living in the community, according to background information in the article. “Reasons for these high vision impairment rates among nursing home residents are not fully understood,” the authors write. “A variety of factors may contribute, including that persons with vision impairment may be more likely to be admitted to nursing homes, nursing home residents may have limited accessibility to doctors’ offices because of lack of transportation and escort availability, residents may not wear spectacles even though they have them, family and health care professionals may believe that cognitively impaired persons do not personally benefit from treatments to improve vision and there is a shortage of eye care professionals who routinely serve clientele living in nursing homes.”

Cynthia Owsley, Ph.D., M.S.P.H., and colleagues at the University of Alabama at Birmingham assessed 380 individuals age 55 or older living at 17 nursing homes in the Birmingham area for visual impairment. Each resident and a family member or guardian was interviewed about the use of eyeglasses and eye care. “Medical records provided information on demographics, chronic medical conditions, date of last eye examination, duration of residence in the nursing home and health insurance,” the authors write. All 17 facilities had licensed optometrists who regularly visited the facility to provide eye care services.

Fifty seven percent of the residents were visually impaired, defined as having visual acuity of worse than 20/40 in the better eye. This compares with rates of approximately 10 percent to 20 percent among adults 60 or older living in the community nationwide. Three-fourths of the participants had abnormal binocular contrast sensitivity, or the ability to detect boundaries between objects and changes in brightness, which is important for mobility and reading.

“It appears that routine eye care may not be taking place for a substantial segment of the nursing home residents in our sample, as implied by our data in several ways,” the authors write. Although 90 percent of the residents had some form of health insurance, 66 percent of them had no reference to eye examinations in their medical records. When asked about their most recent eye exam, 28 percent said it was in the previous year, 20 percent indicated that it was more than two years ago or used words indicating that it was a very long time ago, and one-third did not know.

“Information about the extent to which this visual impairment is remediable was unavailable to the study, so whether high visual impairment rates can be interpreted as underutilization of routine eye care may be questionable. Yet some credence is lent to this possibility based on a previous study estimating that 37 percent of the visual impairment and 20 percent of the blindness among nursing home residents is remediable by refractive error correction,” the authors conclude. “These findings underscore the need to better understand the causes of high visual impairment rates in nursing home residents and to evaluate interventions to improve the visual status of this population.” They also highlight the urgent need for relevant policy formulations and implementations given the potential implications of the findings of these studies.   

References:

1. Arch Ophthalmol. 2007; 125(7):917-924.  

2. Arch Ophthalmol. 2007; 125(7):925-930.