Age Related Macular Degeneration
What is Age Related Macular Degeneration?
Age Related Macular Degeneration (AMD) is a condition that damages the central retina, known as the macula. The retina is the light sensing tissue that lines the inside back part of the eye. Most of the retina is devoted to peripheral vision, night vision and sensing motion. The macula is the only area of the retina that is able to visualize fine details and provide reading and driving vision. When the macula does not function correctly, your central vision can be affected by blurriness, dark areas, or distortion.
Macular degeneration affects your ability to see near and far, and can make some activities—like threading a needle or reading—difficult or impossible.
AMD is the leading cause of legal blindness in the United States in patients over the age of 60. The incidence of AMD increases with age. Thirty percent of people over the age of 70, 40% of people over the age of 80 and 50% of people over the age of 90 are affected with some form of AMD.
Macular degeneration alone does not result in total blindness. Central and fine visual acuity is affected but peripheral or side vision usually remains intact. For example, you can see the outline of a clock but are not able to tell what time it is. Even in more advanced cases, people continue to have some useful vision and are often able to take care of themselves.
Two types of AMD
“Dry” Macular Degeneration (Atrophic, Dry AMD)
- Affects the majority of people with AMD
- Vision loss is usually gradual
- Caused by degeneration of the sensitive cells beneath the retina allowing for the accumulation of “drusen.”
“Wet” Macular Degeneration (Exudative)
- Accounts for 10 to 15% of people with AMD
- Abnormal blood vessels form under the macula and leak fluid or blood
- Leakage results in distorted or blurred central vision
- Vision loss may be rapid and severe
Who is at risk for AMD?
- Family History of AMD
- High Cholesterol
- Excessive sun exposure
What are the symptoms of AMD?
- Blurred vision is the main symptoms of AMD. It can occur in both Dr and Wet AMD. The condition may be hardly noticeable in its early stages. Sometimes only one eye loses vision while the other eye continues to see well for many years.
- Distorted vision where straight lines appear curved is usually due to fluid accumulating from Wet AMD although sometimes the drusen found in Dry AMD may cause this symptom.
How is Macular Degeneration Diagnosed?
Many people do not realize that they have a macular problem until blurred vision become obvious. Your retinal doctor can detect early stages of AMD and diagnose the type of AMD by performing:
- a complete dilated eye exam
- A vision test in which you look at a chart that resembles graph paper (Amsler grid)
- Viewing the macula with special instrumentation
- Optical Coherence Tomography (OCT)
- Tests the macular anatomy at the microspic level
- Non-invasive imagine technique
- Quantifies swelling in the macula to aoi in vision prognosis and determine effectiveness of treatment
- Fluorescein Angiography (FA)
- Tests the retinal circulation to identify the abnormal blood vessels and diagnose Wet AMD
- Vegetable-based dye is injected into your arm and photos of your retina are taken.
How is Macular Degeneration Treated?
Presently there is no cure for AMD. Your doctor may recommend observation if there is no evidence of active Wet AMD.
Although the exact causes of macular degeneration are not fully understood, antioxidant vitamins and zinc may reduce the impact of AMD in some people. In the Age-Related Disease Study (AREDS), taking a high dose combination of vitamin C, vitamin E, beta-carotene and zinc was found to reduce the risk of progression of high Risk Dry AMD. This group of High Risk Dry AMD patients has significant drusen and pigment under the macula, which can be identified by your doctor. The AREDS vitamins, however, are not recommended for smokers due to an increased risk of lung cancer. Other specific formulations are available to this population. You should speak with your doctor to determine if you are at risk for developing advanced AMD, and to learn if supplements are recommended for you.
Injections are the standard of treatment for patients with Wet AMD. Multiple clinical trials have shown that intraocular injections can improve vision in 40% of patients and stabilize vision in 90% of those treated. Typically patients require injections every four to six weeks until the blood vessels and leakage are brought under control. Maintenance injections may also be needed at different intervals. The goal is to optimize vision and control leakage. Patient response can be quite variable so that some patients may only require to or three injections over a two year period to control their Wet AMD, while others require monthly injections to adequately control the leakage and maintain their vision. Your retinal doctor will tailor your treatment to obtain the best visual result for you.
Laser Surgery and Photodynamic Therapy (PDT)
Laser surgery is occasionally used to complement treatment with intraocular injections. Traditional “hot” laser is used less frequently but is an option for a minority of patients. Many clinical studies have shown that for some patients, PDT, or “cold” laser, can diminish the number and frequency of injections to control leakage. Patients undergoing PDT need to avoid direct sun exposure for two days following the PDT procedure for AMD.
Retina Specialty Institute has been involved in multiple clinical trials, including studies involving AMD. Your retinal surgeon or their staff can answer any questions you may have concerning AMD.