Age-related macular degeneration (ARMD)

Macular Degeneration (ARMD) Diagnosis & Treatment for Houston & Galveston from The Eye Clinic of Texas

Macular Degeneration is one of the most common aging eye problems for seniors in Houston.  In fact, Age-Related Macular Degeneration (ARMD) is one of the most common causes of poor vision after age 60. ARMD is a deterioration or breakdown of the macula. The macula is a small area at the center of the retina in the back of the eye that allows us to see fine details clearly and perform activities such as reading and driving.

What are the symptoms?

The visual symptoms of ARMD involve loss of central vision. While peripheral (side) vision is unaffected, with ARMD, one loses the sharp, straight-ahead vision necessary for driving, reading, recognizing faces, and looking at detail.

What causes ARMD?

Although the specific cause is unknown, ARMD seems to be part of aging. While age is the most significant risk factor for developing ARMD, heredity, blue eyes, high blood pressure, cardiovascular disease, and smoking have also been identified as risk factors. ARMD accounts for 90% of new cases of legal blindness in the United States.

Smoking tobacco increases the risk of macular degeneration by two to three times that of someone who has never smoked, and may be the most important modifiable factor in its prevention.

What are the 2 types of ARMD?

Dry ARMD

Dry-ARMD

Dry ARMD takes many years to develop. A specific vitamin regimen has been shown to slow progression of dry ARMD. Your doctor will discuss the vitamin regimen upon diagnosis of Dry ARMD.

Nine out of 10 people who have ARMD have atrophic or “ dry” ARMD, which results in thinning of the macula and leads to loss of central vision. No medical or surgical treatment is available for this condition, however vitamin supplements with high doses of antioxidants, lutein and zeaxanthin have been suggested by the National Eye Institute and others to slow the progression of dry macular degeneration and, in some patients, improve visual acuity.

Exudative or “ wet” ARMD

Wet-ARMD

Until recently, no effective treatments were known for wet macular degeneration. However, new drugs, called anti-angiogenics or anti-VEGF (anti-Vascular Endothelial Growth Factor) agents, can cause regression of the abnormal blood vessels and improvement of vision when injected directly into the vitreous humor of the eye. The injections have to be repeated on a monthly or bi-monthly basis. Examples of these agents include ranibizumab (trade name Lucentis), bevacizumab (trade name Avastin, a close chemical relative of ranibizumab) and pegaptanib (trade name Macugen). Worldwide, bevacizumab has been used extensively despite its “off label” status. The cost of ranibizumab (Lucentis) is approximately US$2000 per treatment while the cost of bevacizumab (Avastin) is approximately US$150 per treatment. Both drugs are made by Genentech.

Promising ARMD research is being done on many fronts. In the meantime, high-intensity reading lamps, magnifiers, and other low vision aids help people with ARMD make the most of their remaining vision.

ARMD and Nutritions

Although the exact causes of ARMD are not fully understood, a recent scientific study shows that antioxidant vitamins and zinc may reduce the effects of ARMD in some people with the disease.

Among people at high risk for late-stage macular degeneration, a dietary supplement of vitamins C, E, and beta-carotene, along with zinc, lowered the risk of the disease progressing to advanced stages by about 25% to 30%. However, the supplements did not appear to benefit people with minimal ARMD or those with no evidence of macular degeneration.

Light may affect the eye by stimulating oxygen, leading to the production of highly reactive and damaging compounds called free radicals. Antioxidant vitamins (vitamins C and E and beta-carotene) may work against this activated oxygen and help slow the progression of macular degeneration.

Zinc, one of the most common minerals in the body, is very concentrated in the eye, particularly in the retina and macula. Zinc is necessary for the action of over 100 enzymes, including chemical reactions in the retina. Studies show that some older people have low levels of zinc in their blood. Because zinc is important for the health of the macula, supplements of zinc in the diet may slow down the process of macular degeneration.

The levels of antioxidants and zinc shown to be effective in slowing the progression of ARMD cannot be obtained through your diet alone. These vitamins and minerals are recommended in specific daily amounts as supplements to a healthy, balanced diet.

It is very important to remember that vitamin supplements are not a cure for ARMD, nor will they restore vision you may have already lost from the disease. However, specific amounts of certain supplements do play a key role in helping some people at high risk for advanced ARMD to maintain their vision.

Prognosis

Macular degeneration can advance to legal blindness and inability to drive. It can also result in difficulty or inability to read or see faces.

Adaptive devices can help people read. These include magnifying glasses, special eyeglass lenses, and computer screen readers

Amsler Grid Test

The Amsler Grid Test is one of the simplest and most effective methods for patients to monitor the health of the macula. The Amsler Grid is, in essence, a pattern of intersecting lines (identical to graph paper) with a black dot in the middle. The central black dot is used for fixation (a place for the eye to stare at). With normal vision, all lines surrounding the black dot will look straight and evenly spaced with no missing or odd looking areas when fixating on the grid’s central black dot. When there is disease affecting the macula, as in macular degeneration, the lines can look bent, distorted and/or missing.