Vision and Alzheimer's Disease -- A Different Way to See the World
For most of us over 40, it's been awhile since our vision was 20:20. But we bought our bifocals and moved on. Unfortunately, for people with Alzheimer's disease, vision problems aren't as easily treated because they are caused not by the eye but by the brain. The person with Alzheimer's has difficulty perceiving what he sees rather than how sharply he sees it.
More than 60 percent of the people with Alzheimer's have a decline in one or more visual capacities. Problems most commonly occur in four areas: motion, depth, color and contrast. And like other Alzheimer's symptoms, not everyone with the disease will experience visual and perceptual problems to the same degree.
It's important for caregivers to understand what people with Alzheimer's may be "seeing" when they look at an object and how that differs from what the caregivers see when they look at the same object. Once that knowledge is gained, steps can be taken to increase safety and lessen confusion.
In 1999, Drs. Charles Duffy and Sheldon Tetewsky of the University of Rochester Center for Visual Studies published research on "motion blindness." They found out that some people with Alzheimer's are unable to sense movement. For affected persons, their view of the world looks like a series of still frames rather than the "movie" most of us see. The doctors theorized that this choppy view of their surroundings causes people with dementia to become lost even in familiar surroundings.
In addition to an ability to see motion, persons with Alzheimer's also may lack the ability to recognize depth --- three-dimensional objects may appear flat. This may make shadows on the floor or a dark rug look like holes in the ground.
Color perception, or the ability to see colors, diminishes with age --- and for people with Alzheimer's there seems to be even greater deficits in the ability to see colors in the blue-violet range. Because blues, blue-greens and blue-violets all look the same, caregivers may want to use the color red to make items stand out. Researchers believe because the retina has more receptors to see red, it's an easier color for most to see.
Increasing color contrasts in a room may help the person with Alzheimer's located items more easily and may also provide a better form of reference. For instance, if your restroom has light blue walls, floor and toilet, it's going to be difficult to see the toilet seat. That's why a red toilet seat, or one that offers great contrast to other colors in the room, is a good choice. Painting a baseboard that contrast with the walls may help the person distinguish where the walls end and the floor begins.
Contrast sensitivity is the smallest difference in intensity that allows you to discern an object from its immediate surroundings. This isn't necessarily a color difference - but like color - the ability to see contrast is reduced in people with Alzheimer's.
Caregivers can increase contrast through lighting: increase the wattage of light bulbs and reduce the amount of glare. Pull down the shades in the early evening to reduce shadows and use several light sources - lamps and overhead fixtures.
Caregiver Tips
To increase safety, make these accommodations for visual changes:
- Diffuse bright light by removing or covering mirrors and glass-top furniture and cover windows with blinds, shades or sheer draperies.
- Add extra lighting in entries outside landings, areas between rooms, stairways and bathrooms because changes in levels of light can be disorienting.
- Place contrasting colored rugs in front of doors or steps to help the individual anticipate staircases and room entrances.
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Information for this story came from an article by Jeanette Rosa-Brady and Tracy Dunne, Ph.D., which originally appeared in the Massachusetts Chapter newsletter.
