Over ten million Americans suffer from vision loss secondary to macular degeneration, more than glaucoma and cataracts combined. The retina is the back lining of the eye, responsible to receive images projected by the lens. The central portion, or macula, is where the ability to focus central vision occurs. As that lining deteriorates, the ability to read, recognize faces or colors, drive a car and see objects in fine detail becomes compromised. In the early changes of macular degeneration, the individual may not yet be aware there are any changes in vision. As the disease progresses, there may be wavy or blurred vision. With additional change, there becomes a loss of the center of the visual field. Imagine looking at a photograph with the center of the picture erased.
Macular degeneration is a little known disease, but research continues. There is evidence that lifestyle, genetics and environment all contribute to the development. People with a family history are at greater risk. Whites are also at greater likelihood than Blacks or Hispanics/Latinos. Those with light colored eyes are more prevalent, as are those with long term UV exposure over time without protection. Those with cardiovascular disease, overweight, eat high fat diet or are females are at greater risk. Smoking doubles the risk of macular degeneration. The threat increases with aging, particularly over age 60.
Because the disease most commonly occurs with age, it is referred to as Age-related Macular Degeneration (AMD). The early stage of AMD may not be evident to the patient. A careful eye exam may identify the initial presence of drusen, the degenerative deposits found in the retina as the disease is diagnosed. Intermediate AMD develops as the number and size of drusen increase, which may provide some degree of visual changes, but still may not necessarily be apparent to the individual. A comprehensive eye exam along with additional testing should show larger and increasing drusen or changes in the retinal pigment. Late AMD has established apparent vision loss. There is another form of macular degeneration known as Stargardt disease. This type is genetic in nature and commonly presents in young individuals, earning the name of early onset or juvenile macular degeneration.
Dry degeneration (atrophic) is far the more common type of macular degeneration (85-90%) while the balance is wet degeneration (exudative). Although both are problems, the wet form is a much more aggressive form of the disease. Dry degeneration involves the proliferation of drusen, where eventually the macular cells will thin and die, causing loss of central vision. Wet degeneration involves overgrowth of blood vessels in the eye, causing bleeding and fluid in the retina, eventually causing scarring and vision loss.
At this time, macular degeneration is an incurable disease. There are opportunities to reduce your risk and slow the progression once diagnosed. Risk reduction may include exercise, diet changes, protecting your eyes from UV exposure and not smoking. Regular eye examinations may be the single most important factor in intervention, especially if you have risk factors or a family history of macular degeneration.
Bradford Croft, DO
East Flagstaff Family Medicine