MACULAR DEGENERATION
Overview
Macular Degeneration (Age Related Macular Degeneration/ ARMD) is the leading cause of blindness in the world. It destroys the very sensitive portion of the retina, called the macula. It usually affects both eyes and is progressive. By destroying the macula, central vision is usually decreased or, sometimes, lost. There are two types of macular degeneration: wet macular degeneration and dry macular degeneration.
Symptoms
Decreased vision, distortion, loss of central vision, difficulty reading, can’t see TV, difficulty seeing road signs
Symptoms of macular degeneration include progressive loss of central vision in both eyes. Macular degeneration affects the central vision and does not involve loss of the peripheral or “side” vision.Distortion may develop in either form of macular degeneration. Large “grey” areas in the central vision may develop called scotomas.
Symptoms of macular degeneration are similar in either dry or wet types. The dry form usually progresses much more slowly. The wet form may develop and affect vision within days to weeks.
Treatment Options
Treatment for Dry (non-exudative) Macular Degeneration – There is presently no treatment for dry macular degeneration.
Treatment for Wet (exudative) Macular Degeneration
- anti-VEGF Injections – Medications such as Avastin® (bevacizumab), Lucentis (ranibizumab) and Macugen (pegaptanib) are commonly injected directly into the eye. These intraocular injections are given as a series of injections, usually in the office setting, and may improve vision and stabilize the eye from further vision loss.
- Laser Photocoagulation – Utilizing a “hot” laser, the abnormal vessels may sometimes be treated directly with laser. This was the original treatment for macular degeneration. Its usefulness is limited by the size and location of the “neovascular membrane” (abnormal blood vessels) as a large scotoma may develop within the central vision. If the are to be treated involves the central macula, a large grey spot will result in the central vision. This “scotoma” is permanent.
- Photodynamic Therapy – Medicine, called Visudyne, is injected intravenously into your body. The Visudyne accumulates in the abnormal, neovascular tissue. Utilizing a “cold” laser, the Visudyne is converted to a substance that is toxic to the neovascular tissue. The treatment does not involve intraocular injections.
- Vitamin Supplements – There are no vitamins or supplements that are an effective treatment for wet macular degeneration. Vitamin supplements, based upon the AREDS formula, are recommended only for a high-risk subset of wet macular degenertion. The effectiveness is limited to decrease the chances of the “wet” form developing in the other eye. Vitamin supplements are not expected to improve the vision or halt the disease.
Causes of Macular Degeneration
“Dry” ARMD
The “dry” form of ARMD is also known as non-exudative macular degeneration. It is the most common form of ARMD and accounts for about 90% of all cases that have the disease. Dry ARMD progresses slowly, typically affects both eyes, but does not usually cause severe vision loss when compared to “wet” ARMD. Advanced cases of dry ARMD, called geographic atrophy, may cause severe vision loss. At present, there is no treatment for any form of dry ARMD.
“Wet” ARMD
The “wet” for of ARMD is also know as exudative macular degeneration. It accounts for a minority of the cases of all ARMD, but usually is responsible for causing the most severe vision loss. This form usually affects one eye, but no always. The hallmark of the disease is the presence of abnormal blood vessels that form within the layers of the retina, called choroidal neovascularization. Treatments currently used for treating “wet” macular degeneration include anti-VEGF inhibitors (drugs that neutralize the effects of Vascular Endothelial Growth Factor), photodynamic therapy and others.
Tests and Diagnosis
- Visual Acuity
- Amsler Grid (used also for self-monitoring)
- Dilated Eye Exam
- Fluorescein Angiography
- Retinal Photographs
- Optical Coherence Tomography
Prognosis
Most patients with dry macular degeneration do not suffer much of a visual impairment. Vision loss is mild to moderate and may limit reading and driving. It does not cause blindness as the peripheral vision is spared.
Patients with wet macular degeneration may suffer significant loss of central vision. Vision loss may occur over days, weeks or months. Legal blindness may occur in either dry or wet forms, but is more common in wet macular degeneration.
Prevention
There is no actual way to prevent the disease, but limiting visual loss is possible by early detection. By recognizing the symptoms of macular degeneration, early treatment may be helpful . Both forms of macular degeneration are progressive.
Vitamins have not been shown to prevent the disease nor have any specific diets been proven to be helpful. Many foods and supplements are actually being studied by the National Eye Institute (AREDS 2).
Complications
Significant vision loss resulting in “legal blindness” may occur in either wet or dry macular degneration.
When to Consult Your Doctor
Call your doctor if you experience sudden changes in central vision, including distortion (metamorphopsia) that are persistent.
“My Practice”
Patients with macular degeneration are usually older than 55 years old, have signs of macular degeneration in both of their eyes and may have experienced some slow, insidious vision loss. Most have dry macular degeneration, and, as we have discussed there is no known treatment. Perhaps 85 – 90% of macular degeneration is of the “dry” variety.
Patients with “wet” macular degeneration also lose central vision, but the symptoms develop over a much quicker time frame. Patients with symptoms of new vision loss, including distortion, are encouraged to call their doctor.
A fluorescein angiogram is usually performed to demonstrate the presence of neovascularization. If present, therapy may be instituted soon, to prevent further vision loss. The earlier the diagnosis is made, the better.
Most often, I treat “wet” macular degeneration with anti-VEGF intraocular injections. The laser photocoagulation and Photodynamic Therapy are not as useful to me.