Age-related macular degeneration (AMD) is a complex degenerative retinal disease that is a leading cause of vision loss among people age 50 and older. It causes damage to the macula, a small area in the center of the retina and the part of the eye needed for sharp, central vision. The retina turns light into electrical signals which travel through the optic nerve to the brain, where they are translated into the images we see. When the macula is damaged, the center of your vision may appear blurry, distorted, or dark.
Age is a major risk factor for AMD, with most cases occurring after age 60. Other risk factors for AMD include smoking, Caucasian race, family history of AMD, history of heart disease, elevated serum lipids, and overexposure to bright sunlight (especially UV rays). Lifestyle choices such as exercise, avoiding smoking, maintaining normal blood pressure and cholesterol levels, and eating a healthy diet rich in green, leafy vegetables and fish can reduce your risk or slow AMD progression.
There are two types of AMD
Non-exudative or Dry AMD
This is the most common and often less severe form of AMD. In this type of macular degeneration, the transport of wastes and nutrients by the retinal pigment epithelium (RPE) slows down and results in waste build up under the retina, forming yellowish deposits known as drusen. The deterioration of the retina is associated with the formation of these drusen under the macula. This phenomenon can lead to significant thinning of the macula, causing dysfunction of the photoreceptors which correlate with visual changes. Large regions of photoreceptor loss called geographic atrophy may occur and result in a blind spot or scotoma in the central vision. The amount of central vision loss is directly related to the location and amount of such atrophic changes.
Aside from managing risk factors and vitamin therapy, there is currently no other prevention or treatment for dry AMD. A series of important studies, the Age-Related Eye Disease studies (AREDS) conducted by the National Eye Institute, showed that a defined subgroup of patients with AMD who were at risk for developing the advanced form of the disease benefitted from taking the following daily supplements:
- Vitamin C (500 mg)
- Vitamin E (400 IU)
- Lutein (10 mg)
- Zeaxanthin (2 mg)
- Zinc (80 mg)
- Copper (2 mg)
If you have dry AMD, make sure to tell your ophthalmologist about any changes in your vision immediately. Regular exams along with self-monitoring using the Amsler Grid (have this be a term patients can click on that will take them to the Amsler Grid section) are necessary for preserving your vision. Patients with dry AMD can develop wet AMD, for which effective treatment is available if instituted in a timely manner.
Exudative or Wet AMD
This form of AMD is caused by abnormal blood vessels that leak fluid or blood into the macula and originate in the context of choroidal neovascularization (CNV). In most cases, the first sign of fluid under the macula is the appearance of distorted straight lines. Regular testing with an Amsler Grid (have this be a term patients can click on that will take them to the Amsler Grid section) is recommended to help detect problems early. If detected early, new blood vessels can be treated before they cause too much damage. Otherwise, untreated fluid and CNV can cause the overlying photoreceptors to become permanently damaged and lead to macular scarring, which in most cases leads to central vision loss.
Wet AMD Treatment
The most effective treatments to date for wet AMD are anti-angiogenic or anti-VEGF medications. Vascular endothelial growth factor (VEGF) is a substance produced by the body to regulate the growth and health of blood vessels. In wet AMD, an excess of VEGF leads to formation of new, unhealthy blood vessels. Several drugs are available to block VEGF and help control wet AMD. These intravitreal injections need to be carried out with a certain regularity to improve and then maintain visual acuity. As the disease stabilizes and improves, often the intervals between injections can be stretched out.
Anti-VEGF intravitreal injections have provided wet AMD patients with unprecedented visual acuity gains and disease stability for many years. It is imperative that anyone who has wet AMD receives treatment in a timely fashion and maintains treatment according to the recommendations of his/her retina specialist. At BEI, we strive to create an environment where such treatments are tailored to each individual patient's needs and are provided in the safest and most comfortable manner possible.
Amsler Grid Chart Testing
One of the first signs of macular degeneration can be wavy, broken, or distorted lines or a blurred or missing area of vision. The Amsler Grid is a self-monitoring tool that allows you to spot these distortions early. Early detection of wet AMD is critical because treatment is most successful when performed before damage occurs. Since dry AMD can lead to development of wet AMD, you should use the Amsler Grid to check for such progression at home. If you notice any changes on the Amsler grid, contact us promptly.
Instructions for use:
View the chart (with your reading glasses on) at normal reading distance.
Completely cover one eye and look at the central dot on the chart.
Notice if there are any areas within the grid that appear gray or black, or if there are any areas where the straight lines appear bent, crooked, or missing.
Now cover the other eye and repeat the test.
Check the chart regularly according to your doctor's instructions.
Call your doctor if new changes occur.