Age-related macular degeneration (AMD) is the most common cause of vision loss in older adults in the United States. Like most other eye conditions, it is a result of some defect disturbing light’s journey through the eye to the retina. What is different about AMD, however, is that it occurs in the retina itself, and the retinal cells themselves are dying. The retina houses the light-sensitive photoreceptors that send the messages to the brain about what you are seeing, and so when those cells are dead it is like a hole in your vision. Unfortunately since this happens in the macula, the center of the retina, it is center vision that is compromised first.
There are two types of AMD, called dry and wet macular degeneration. Dry AMD is more common and occurs from the slow break down of the retinal cells, while wet AMD is actually caused by scarring on the retina due to a process called neovascularization. This is when blood vessels begin to grow where they shouldn’t, behind the retina, causing the damage to the macula. This form is rarer and is considered an advanced form of AMD, and it also often degenerates from dry AMD.
The symptoms of macular degeneration are also the side effects: vision loss. There is no pain preceding or coinciding with the progression of the condition. There are, however, signs that an optometrist or other eyecare practioner may be able to spot with a retinal exam or other tests. Many patients are given what is called an Amsler grid test. This simple grid with a dot in the center will appear to have blurred and curved lines to a patient of AMD, and many patients report noticing similar changes in their vision in their day-to-day life.
The most common cause of macular degeneration is aging, though smoking has also proved to be a cause. Other studies suggest that you may be at higher risk if you have a lot of exposure to sunlight, are white, female, have light eye color, have family members with AMD, are obese, farsighted, or hypertensive. These findings are only in the preliminary stages and not all studies agree at this time.
AMD is a disease that is very individual, meaning that there is no way of predicting how a diagnosis of AMD will progress. Many people live for years with dry AMD and only slight vision loss, and some of those do not suffer much beyond that. Others will perhaps suffer a sudden switch from dry to wet AMD, while others have conditions that move much more swiftly. Dry AMD has fewer treatments than wet AMD, for which there are drugs to try and stop the growth of new blood vessels, or at least slow it for some time. For dry and wet AMD patients are asked to monitor their vision loss regularly and encouraged to take in more of nutrients like zinc and vitamins A, C, and E, which studies show are helpful in slowing the progression of AMD. Treatment options are always being researched.
Samuel, Michael A. Macular Degeneration: A Complete Guide for Patients and their Families.