Written by Catherine Borgeson, O.D.
Board Certified Optometric Physician
The part of the eye responsible for seeing color and “20/20 vision” or details like faces, television, roads, and reading material, is the macula. Age-Related Macular Degeneration (AMD) is a common eye disease where the macula loses its function. Since AMD is an age-related disorder, it affects about 1 out of 5 people between the ages of 70-84. By age 85, nearly half of the population will show signs of AMD; however, it can begin as early as age 50.
Smoking is the number one risk factor you can control. If you smoke, it increases the risk of both developing AMD and faster progression. Another factor you can control is your overall health and diet. Having uncontrolled high blood pressure, high cholesterol, and being obese increases your risk, while having a healthy diet full of leafy green vegetables and omega-3 (fish, flaxseed, and walnuts) and exercise will decrease your risk.
Risks that are out of your control are family history, race, and age. AMD runs in families, so if a parent or sibling has it, you are more likely to develop it. Caucasians also have a higher instance of AMD than people of African, Hispanic, or Asian descent. Lastly, being over the age of 55 is a risk (at least until someone finds the fountain of youth, in which case, let us know if you find it).
Types of AMD
Dry (Non-Exudative) Macular Degeneration
The majority of AMD is the dry form, which is when the retina (the light sensitive part of the eye) starts to thin out. Additionally, there may be pigmentary (or color) changes and there can be drusen build-up, which are lumps of cell waste that disrupt the smooth surface of the retina. These changes are concentrated in the macula and can cause a gradual decline in central vision. Typically, the visual changes occur in both eyes over years to decades, but they are frequently asymmetric affecting one eye more than the other.
Wet (Exudative) Macular Degeneration
About 10% of patients with AMD will develop the wet form, which is when unstable blood vessels grow and leak fluid under the retina. If untreated, this can cause a rapid decline in central vision over the course of days to weeks. Note, the earlier AMD is treated, the more effective the treatments for slowing or stopping the visual decline are.
Early Signs of AMD
In the beginning, people with early AMD can have normal vision. Over time, they may notice colors look faded, greys blend together, and their vision is not as sharp. Anyone over 65, especially those with a family history of AMD, need to have an annual dilated eye exam.
Monitoring and Treatments for AMD
Patients with AMD are given an Amsler grid to catch any changes to their vision. To use an Amsler grid, with your reading glasses on, cover one eye and look at the lines; if any of the lines are wavy or distorted, make sure to tell your eye doctor. Do not forget to check and compare the grid with the other eye, too.
If you are diagnosed with AMD, your doctor will order a baseline scan called an OCT that takes a laser scan of the layers of the retina. This helps check for progression of AMD and for early signs of fluid under the retina. The doctor may also recommend taking eye vitamins based on the Age-Related Eye Disease Study II. This study showed that taking high doses of certain vitamins slows the progression of AMD.
If the AMD advances from the dry to wet form, the patient needs small injections to stop the leaky blood vessels. This treatment is usually very effective at reducing the fluid build-up and improving vision.
Remember, the early detection of AMD and other eye conditions is crucial to maintaining your vision. If you or a family member have not had a dilated exam in a while, it would be a good idea to schedule one.