Macular Degeneration

Macular degeneration is a disease of the macula, an area of the retina at the back of the eye that is responsible for fine detail vision. Vision loss usually occurs gradually and typically affects both eyes at different rates. Even with a loss of central vision, however, color vision and peripheral vision may remain clear.

Macular degeneration is divided into two forms. The “dry” form is the most common and accounts for about 90 percent of all macular degeneration cases. It involves thinning or deterioration of the tissues of the macula or the formation of abnormal yellow deposits called drusen. Progression of dry macular degeneration occurs very slowly and does not always affect both eyes equally.

The “wet” form, also called the exudative or neovascular form, accounts for the other 10 percent. It is the more severe form and can be associated with more rapid and severe vision loss. Wet macular degeneration is associated with the development of abnormal blood vessels that grow within the layers of the retina. The “neovascularization” can bleed, leak and physically cause damage to the retinal layers. Wet macular degeneration also affects both eyes and can destroy vision in a matter of days or weeks. Vision loss is often severe.

There is no pain associated with AMD, but the symptoms of this disease can have a profound effect on daily routines. As the cells of the macula break down, people suffering from dry AMD will register straight lines as wavy or see blurred spots in the center of their vision. Sufferers of wet AMD, or advanced AMD, may experience rapid vision loss. As abnormal blood vessels grow behind the macula and begin to leak, central vision deteriorates quickly. Here are some more specific symptoms that may be experienced:

• Early macular degeneration may cause little, if any noticeable change in vision
• Difficulty reading without extra light and magnification
• Seeing objects as distorted or blurred, or abnormal in shape, size or color
• The perception that objects “jump” when you try to look right at them
• Difficulty seeing to read or drive
• Inability to see details
• Blind spot in center of vision

The root causes of macular degeneration are still unknown. Women are at a slightly higher risk than men. Caucasians are more likely to develop macular degeneration than African Americans and those with a family history of macular degeneration are at greater risk of developing the disease.

• Age: Macular degeneration is the leading cause of decreased vision in people over 65 years of age.
• Heredity: Macular degeneration appears to be hereditary in some families but not in others
• Long-term sun exposure
• Smoking
• High blood pressure
• High cholesterol
• Hypertension
• Nutritional deficiencies
• Diabetes
• Head injury
• Infection

Diagnosis

Your eye doctor can identify changes of the macula by looking into your eyes with various instruments. A chart known as an Amsler Grid can be used to pick up subtle changes in vision.

Angiography is the most widely used macular degeneration diagnostic test. During the test, a harmless orange-red dye called Fluorescein will be injected into a vein in the arm. The dye travels through the body to the blood vessels in the retina. A special camera takes multiple photographs. The pictures are then analyzed to identify damage to the lining of the retina or atypical new blood vessels. The formation of new blood vessels from blood vessels in and under the macula is often the first physical sign that macular degeneration may develop.

Optical Coherence Tomography (OCT) uses light waves to create a contour map of the retina and can show areas of thickening or fluid accumulation.

Treatment

In the early stages of macular degeneration, regular eye check-ups, attention to diet, in-home monitoring of vision and possibly nutritional supplements may be all that is recommended.

Diet and nutritional supplements

There has been active research on the use of vitamins and nutritional supplements called antioxidants to try to prevent or slow macular degeneration. Antioxidants are thought to protect against the damaging effects of oxygen-charged molecules called free radicals. A potentially important group of antioxidants are called carotenoids. These are the pigments that give fruits and vegetables their color. Two carotenoids that occur naturally in the macula are lutein and zeaxanthin. Some research studies suggest that people who have diets high in lutein and zeaxanthin may have a lower risk of developing macular degeneration. Kale, raw spinach, and collard greens are vegetables with the highest amount of lutein and zeaxanthin. You can also buy nutritional supplements that are high in these and other antioxidants.

There have been major strides in the treatment of macular degeneration over the last decade. Eye injections of medicines that inhibit bleeding have been the major recent advancement for wet macular degeneration. Very rarely is any type of laser used nowadays. Avastin, Lucentis, and the newest drug Eylea are all being used with good success. All of these are available at Baltimore Eye Physicians. These injections help stabilize vision, preventing it from getting worse, and at times even improving vision. The eye is numbed thoroughly and a very tiny syringe is used to instill the medication with little to no discomfort. Bleeding over the white part of the eye is not uncommon, but poses no threat to sight. This resolves in a week, usually without treatment.