Summary: People who give up activities because of age-related macular degeneration may be more likely to have memory loss than those who find ways to stay active despite their loss of vision.
In the last few years, several studies have shown poor eyesight (macular degeneration in particular) is associated with memory loss. In a large study by the Age-Related Eye Disease Study Group, the worse participants’ vision was, the more likely they were to do poorly on memory tests.
It’s unclear why there is a link between macular degeneration or poor vision and memory loss, however. Scientists have put forth different theories:
1. in macular degeneration, abnormal forms of the protein called beta amyloid are deposited on the retina. In Alzheimer’s, abnormal forms of the same protein are deposited in the brain. This could mean the two diseases have the same origin.
2. a lack of visual sensory input could cause changes in the brain
3. low vision could cause people to stop participating in stimulating activities thought to reduce the risk of memory loss.
Dr. Robin Casten and her colleagues at Jefferson Medical College in Philadelphia decided to test the third hypothesis in a study of 206 people with no apparent memory loss who had age-related macular degeneration. The researchers tracked participation in six types of activities: reading, exercise or sports, hobbies, spectator activities, social activities and cards or games. They found that each activity dropped due to vision loss seemed to increase the risk of memory loss over the three year study period.
Dr. Casten cautions that the assessment of memory loss was based on interviews of family members and caregivers, rather than on neuropsychological testing. Still, this study seems to confirm that cognitive decline in people with poor vision is at least partly due to reduced activities.
What does this mean if you have poor vision? “The most important thing we see in research on cognitive impairment as well as research on vision loss is that people need to stay engaged,” says Dr. Casten. “They should try to find ways to compensate for any disabilities, or find substitute activities.”
Her advice for people with serious vision loss? “See an optometrist who specializes in low vision rehabilitation,” she says, “and get prescription magnifiers if possible, rather than ones available over-the-counter. Low vision reading machines, although expensive, can be helpful. An occupational therapist specializing in low vision can conduct a complete assessment of your home environment and suggest modifications to improve safety and functionality and reduce the risk of falls. Modifications might include procedures or devices to use when cooking, enhanced lighting or painting trim around doors to clearly mark exits.”
What if you already have memory loss and now your vision is failing? “For these people in particular,” says Dr. Casten, “once vision loss sets in, they can benefit from developing strategies that don’t require vision to remember things. For instance, voice notes on a handheld recorder might replace paper lists, and setting an alarm might replace a written reminder. It’s important to find cues that aren’t vision dependent.”