Alan Frischer, MD, MPH
It’s hard to grow old. I have yet to hear from even one of my patients that getting older is a breeze. Age-related macular degeneration (AMD) develops as we age, and is the leading cause of severe, irreversible vision loss in those over 60. One in five over 75 suffer from it. What is this terrible disease, and how can we treat it? Can it be prevented?
The retina is the light-sensing nerve tissue at the back of the eye. Age-related macular degeneration occurs when the small central portion of the retina (the macula) deteriorates. Although AMD almost never leads to complete blindness, it is nonetheless extremely debilitating.
There are two main types of AMD. Most starts as the dry type, but 10-20% of the time it progresses to the wet type, which can result in more serious vision loss. It is always bilateral (occurring in both eyes), but does not necessarily progress at the same pace in both eyes. It is possible to experience the wet type in one eye and the dry type in the other.
With the dry form, there are yellow deposits in the macula. A few small deposits may not cause changes in vision, but as they increase in both size and number, vision becomes dimmer and distorted. This is mostly noticed when reading. In more advanced stages of dry macular degeneration, there is also a thinning of the light-sensitive layer of cells in the macula, which leads to atrophy (tissue death), and blind spots occur in the center of the vision.
With the wet form, there is a growth of abnormal blood vessels from underneath the macula. These blood vessels leak blood and fluid into the retina, causing distortion of vision that makes straight lines look wavy, as well as blind spots and loss of central vision. These abnormal blood vessels and their bleeding eventually form a scar, leading to permanent loss of central vision.
How do you know if you have macular degeneration? Watch for blurred or hazy vision, where the center of the view looking straight ahead is blurry. Some people experience blank spots in the main line of vision. There may be flashes of light in one or both eyes, halos that appear around lights at night, or a change in the color of the iris or clarity of the cornea. Even with magnification and more light, reading and writing become increasingly difficult.
What treatments are available? In the early stages of dry AMD, taking some antioxidants may reduce vision loss. For later stages of dry AMD there is currently no approved treatment. There is a treatment that can slow the progression of wet macular degeneration. Vascular Endothelial Growth Factor (VEGF) is a naturally occurring protein in the body, and its normal role is to trigger formation of new blood vessels. However, in certain diseases (including wet AMD) it is also associated with the growth of abnormal new blood vessels in the eye. An injection is available that can slow down this process. Eye drops are currently under study which may be able to replace the need for an injection.
Can we reduce our risk for macular degeneration? Very possibly. Stop smoking cigarettes, eat fatty fish like salmon, tuna, mackerel or sardines twice a week, and eat plenty of vegetables and fruits. Wear sunglasses for protection. Researchers with the Age-Related Eye Disease Study (AREDS) reported that nutritional supplements containing omega 3 fatty acids, vitamin C, vitamin E, beta-carotene, zinc and copper may reduce the risk of developing advanced age-related macular degeneration.
Age-related macular degeneration is truly a terrible disease, however, there is significant progress in research being made and the future is promising.