By Linda Conlin, Pro to Pro Managing Editor
Can declining vision in the elderly be associated with cognitive decline? A recent article in the New York Times reported on a study published in JAMA Open Network indicating just that. The study used data from the Baltimore Longitudinal Study of Aging for 2003 to 2019. The more than 1,200 participants in the study were aged 60 to 94 years. Visual function was evaluated for acuity, contrast sensitivity, and stereo acuity. Cognitive function was evaluated for language, memory, attention, executive function, and visuospatial ability (the ability to identify visual and spatial relationships among objects). All participants had normal cognitive function at the initiation of the study, with standard deviations (SD) in visual acuity of 0.16, and contrast sensitivity of 1.9.
Participants underwent vision and cognitive testing every 1-4 years, depending on age, with the youngest group tested every 4 years, the mid-range group every 2 years, and the oldest group every year. Language, memory, attention, and cognitive function were evaluated using standardized tests. Visual acuity was tested with participants wearing their prescription glasses, a Pelli-Robson chart measured contrast sensitivity by finding the lowest contrast letters participants could read correctly, and stereo acuity was measured using the Stereo Fly Test Circles. Comorbidities were considered in the data analysis.
The analysis showed an association between declines in specific visual functions and declines in specific cognitive functions. In the early part of the study, worse visual acuity was associated with declines in language, attention, executive function, and visuospatial ability. Worse contrast sensitivity was associated with lower scores in visuospatial ability, and stereo acuity impairment was associated with lower scores on tests of executive function. Data from the latter part of the study showed that impaired contrast sensitivity was associated with declines across more cognitive domains than other measures of visual functioning, suggesting that impaired contrast sensitivity may be associated with greater cognitive decline than visual acuity, which we may have expected to have a greater impact.
Prior studies have documented an association between vision impairment and cognitive decline. There are several hypotheses as to why the association exists. One is that when the brain must put more effort into interpreting images, other functions decline. Other results of vision impairment are depression, social isolation, loss of cognitively stimulating activities (e.g. reading), and less physical activity, which also have an impact on cognitive function. There are safety issues, too. Someone who can’t see well is more likely to sustain an injury that results in hospitalization and so further isolation and depression.
Certainly, identifying and correcting vision loss early can help. When prescription glasses only go so far to correct vision impairment as with AMD, we need to know more about low vision aids. It begins with relatively simple accommodations such as colored strips on stair steps, varying textures of furniture, and color-coding objects for easier identification. Large print and audio books are available from libraries and may be delivered to the home. Magnifiers, telescopes, and accessibility features on smart phones, computers, and tablets are part of the range of devices available to help people live more independently and preserve cognitive function.
Learn more about identifying patients who can benefit from low vision devices with our CE, Maximizing the Opportunities for Magnification, at 2020mag.com/ce.
Article shared from 20/20 Magazine.