The macula is the central portion of the retina, the light sensitive tissue that lines the back of the eye, which allows you to appreciate fine detail. Age related macular degeneration (AMD), is a disease associated with aging that over time destroys this central tissue. There are two forms of this disease process: a dry form and a wet form. Both forms have the end result of causing vision loss.
Dry AMD is caused by a slow break down or death of the macula over time. Wet AMD, on the other hand, is caused by proliferation of abnormal blood vessels at the level of the macula. These blood vessels are fragile and have a tendency to leak blood and fluid. Both processes lead to blurring of the central vision, but the changes occur more rapidly in wet AMD. The onset of the disease can be accompanied by the development of drusen, yellowish deposits in the back of the retina. The presence of drusen alone does not translate into macular degeneration. Studies have shown that there is an increase risk of developing macular degeneration correlating with an increased size or number of such deposits.
Risk factors for macular degeneration include being Caucasian, smoking, having a family history of the disease, and female gender among many others.
The early symptoms for patients with dry AMD are a blurring of vision. Patients most often have a hard time recognizing people and objects. They often require more light and magnification when reading or performing other tasks. With wet AMD, the earliest symptoms involve a distortion of images. Often times, straight lines can appear crooked. Over time, this can progress to a loss of central vision.
No form of treatment exists for dry AMD. Studies have shown that taking a special formulation of antioxidants and zinc can reduce the risk of the disease progression to an advanced stage.
Wet AMD, on the other hand, does have many treatment options available. This includes laser treatment aimed at destroying the abnormal blood vessels to receiving injections of medications in the eye. Medications have been developed to block the production of abnormal blood vessels and promote resorption of blood and fluid that has already leaked into the macula. Patients commonly require multiple injections in order to have a positive effect. If despite treatment patients continue to have poor vision, a low vision evaluation is recommended. The patient can be introduced to a variety of visual aids that can improve their quality of life.
On a daily basis, patients are encouraged to monitor their vision using an Amsler grid. This is a grid analogous to a checkerboard that allows you to detect any missing areas or visual distortions. If any changes are noted on the amsler grid, you should immediately get in touch with your ophthalmologist to schedule an exam.