What is macular degeneration?
Macular degeneration is the physical disturbance of the centre of the retina called the macula. The macula, which is about the size of the capital letter “O” in this sentence, is the part of the retina which is capable of our most acute and detailed vision. We use the macula for reading, driving, recognizing faces, watching television, and fine work. Macular degeneration is the leading cause of legal blindness in people over age 55. (Legal blindness means that a person can see 6/60 or less with glasses.) Even with a loss of central vision, however, color vision and peripheral vision may remain clear. Vision loss usually occurs gradually and typically affects both eyes at different rates.
What causes macular degeneration?
The root causes of macular degeneration are still unknown. There are two forms of age-related macular degeneration, “wet” and “dry”. Seventy percent of patients have the “dry” form, which involves thinning of the macular tissues and disturbances in its pigmentation. Thirty percent have the “wet” form, which can involve bleeding within and beneath the retina, opaque deposits, and eventually scar tissue. The “wet” form accounts for ninety percent of all cases of legal blindness in macular degeneration patients.
Different forms of macular degeneration may occur in younger patients. These non-age related cases may be linked to heredity, diabetes, nutritional deficits, head injury, infection, or other factors.
How is macular degeneration detected?
Declining vision noticed by the patient or by an ophthalmologist during a routine eye exam may be the first indicator of macular degeneration. The formation of deposits of waste material in the macula, known as “drusen,” is often the first physical sign that macular degeneration may develop. Later, patches of noticeably thin retina or abnormal blood vessels with bleeding and leakage beneath the macula may occur. In addition, the following signs may be indicative of macular problems. Anyone experiencing these symptoms should consult an ophthalmologist immediately:
a. Straight lines appear distorted and, in some cases, the centre of vision appears more distorted than the rest of the scene.
b. A dark, blurry area or “white-out” appears in the centre of vision.
c. Colour perception changes or diminishes.
Is early detection important?
Early detection is important because a patient destined to develop macular degeneration can sometimes be treated before symptoms appear, and this may delay or reduce the severity of the disease. Furthermore, as we develop better treatments for macular degeneration, whether they are medicinal, surgical, or low vision aids, those patients diagnosed with macular degeneration can sooner benefit from them.
If I have macular degeneration in one eye, will it develop in the other?
Yes, this is usually the case. In the early stages, only one eye may be affected, but as the disease progresses, both eyes are usually affected.
Is there a cure for Macular Degeneration?
At this time there is no known cure for macular degeneration. However, there are ways to arrest macular degeneration, depending on the type and the degree of the condition. These range from nutritional intervention to lessen the risk of progression to treatment with special drugs such as Avastin, Lucentis or Eylea or with photodynamic therapy to close the leaking vessels. There are also low vision aids and techniques for maximizing the use of peripheral vision to help patients adapt better to their loss of central vision.
Can nutrition help treat macular degeneration?
Some scientists have suggested an association between macular degeneration and high saturated fat, low carotenoid pigments, and other substances in the diet. There is evidence that eating fresh fruits and dark green, leafy vegetables (such as spinach and collard greens) may delay or reduce the severity of age-related macular degeneration. The Age Related Eye Disease Study found a beneficial effect from high dose supplementation with vitamins C, E and Beta carotene, along with zinc. They found a reduction in risk of visual loss of 28% in those with at least moderate age-related macular degeneration.
Is macular degeneration hereditary?
Macular degeneration appears to be hereditary in some families but not in others. Since macular degeneration affects most patients later in life, it is difficult to study successive generations in a family. Recent studies of twins indicate that both genetic and non-genetic factors play important roles in age-related macular degeneration. Research to determine the genes associated with hereditary macular degeneration will help lead to early detection, early intervention, and possible cures.
Does sunlight affect macular degeneration?
Yes. It has been demonstrated that the blue rays of the spectrum seem to accelerate macular degeneration more than other rays of the spectrum. This means that very bright light, such as sunlight or its reflection in the ocean and desert, may worsen macular degeneration. Sunglasses that block out the blue end of the spectrum may decrease the progress of the disease. Again, more research is needed in this area.
Does hypertension (or medication for hypertension) affect macular degeneration?
Yes. Hypertension tends to make some forms of macular degeneration worse, especially in the “wet” form where the retinal tissues are invaded by new blood vessels. The medications used to treat hypertension have not been shown to have any direct effect on macular degeneration, but they may slow progression of the disease by reducing hypertension.
Does smoking or second-hand smoke contribute to macular degeneration?
Yes. Any type of smoking or exposure to tobacco smoke can accelerate the development of the “wet” type of macular degeneration.