Tip: What to know about vision loss

When many of us hit our 40s, reading becomes more difficult because the once-clear type now appears blurry. While this normal part of aging is easily correctable with reading glasses, more serious changes in eyesight that often begin about the same time are not normal because they are caused by eye diseases. Known collectively as low vision, the condition is defined as a significant loss of eyesight that cannot be corrected with conventional glasses or by medical or surgical means.

"As we get older, most people will eventually develop cataracts, some will develop glaucoma and a significant number of people will develop some macular degeneration," says Dr. Ira Udell, chairman of ophthalmology at North Shore University Hospital-LIJ Health System.

There are frustratingly few treatments for the diseases that cause low vision, although just a few years ago there were virtually none. In the case of an advanced form of age-related macular degeneration known as wet AMD, Udell says a treatment called anti-VEGF therapy has shown promise. "Significant improvements have come with the injection of these agents," he says. The treatment can stop the progression of the disease and in some cases restore some vision.

Typically, a person first develops what is known as dry AMD, which progresses so slowly that changes in vision may be unnoticed. If caught at an early stage, significant vision loss may be averted. If the disease progresses to the wet stage, vision loss is often rapid. AMD is the leading cause of severe vision loss in people 50 and older, according to the American Optometric Association.

As for glaucoma, any vision loss is permanent. "Glaucoma is sort of the silent loss of vision, because you may not realize it until it's very late," Udell says. "All you can do is try to prevent progressive damage, but you can't reverse what's already occurred."

Because catching these conditions early can often prevent significant vision loss, the American Academy of Ophthalmology recommends that people ages 40-64 get a vision checkup every two to four years. Those 65 and older should get complete eye exams every one to two years.

For more information on low vision, go to the National Eye Institute's webpage at 1.usa.gov/lowvision.