What is Age-Related Macular Degeneration?
Age-related macular degeneration (AMD) is a condition that affects the macula, which is located in the center of the retina. Spanning less than 2 millimeters in diameter, the macula is the central portion of the retina that allows us to see fine detail. Any disruption of the macula results in a marked change of vision. Cells of the retina convert light to chemical and electrical impulses, which are conveyed to the brain where they are converted to what we see. AMD affects 1.5 million Americans. It is the leading cause of visual impairment to people over age 65.
Are There Different Types of AMD?
Dry macular degeneration accounts for approximately 80% of all cases of AMD, but only 20% of all severe vision loss. It is caused by the aging and thinning of the blood vessels under the macula and results in a mild, gradual, usually mild, loss of vision that is especially notable during activities such as reading.
Wet macular degeneration occurs in the other 20% of AMD cases and accounts for the majority of all severe vision loss. It poses a significantly more progressive and severe loss of vision and is caused by an abnormal leakage of fluid and or blood from the vessels under the retina. In Some cases these blood vessel abnormalities extend into the core of the retina itself. This leakage disrupts the central-viewing function of the macula and results in visual distortion and eventually loss of central vision.
Dry AMD can convert to wet AMD, but the reverse is never the case. AMD almost always involves both eyes in some manner.
What Are the Warning Signs?
You should see your ophthalmologist, optometrist, or retinal specialist if you experience any of these symptoms:
- Decreased visual sharpness
- Blind spots
- Turning away from an object to see it better
- Distorted vision
- Decreased color perception
How important is Early Detection?
It is extremely important. Treatments seem to offer the highest success rates when administered in the earliest stages of development of AMD.
You can take a proactive role in early detection by following a few simple steps:
- Learn the warning signs
- Schedule regular eye checkups
- Understand the risk factors
- Conduct daily self-exams making sure to check each eye independently while reading and performing other visual tasks. After age 60 doing this daily is a good habit to acquire.
The Amsler Grid is sometimes used as an additional tool for monitoring a patient’s central visual field. The Amsler Grid consists of evenly spaced horizontal and vertical lines printed on black or white paper. A small dot in located in the center of the grid for fixation. While staring at the dot, the patient looks for wavy lines and missing areas of the grid.
What Are the Risk Factors for AMD?
GENETICS: Studies of twins indicate that AMD can have a genetic component. People with a family history of AMD should see an eye care professional for regular and thorough eye exams.
EYE CHARACTERISTICS: A few eye characteristics have been linked to a higher risk of developing AMD. Some studies have shown a higher risk for AMD in people with blue or hazel eyes. Farsightedness may also increase the risk.
CARDIOVASCULAR, ENVIRONMENTAL, AND NUTRITIONAL: All three of these risk factors l11ay be reduced by a change in behavior. Quitting smoking helps. Several studies have also shown a link between high blood pressure and AMD and between high dietary fat and AMD.
How is AMD Treated?
Major advances have occurred in recent years in the treatment of AMD.
Physicians at NRI are proud to have played a significant role in the development of these new treatments and are leading innovators in the development of future treatments. The new techniques include improved computerized imaging of the blood vessels under the macula that are either thinning in the case of dry AMD or leaking in eyes with wet AMD. New imaging techniques also have been developed to evaluate the structure of the retina to determine where the retina is swelling in response to leakage from the underlying blood vessels. More precise detection of the blood supply of the macula and sites of leakage allow better use of advanced treatments such as Feeder Vessel Treatment where a tiny laser beam can be used to treat the individual blood vessel leading to the area of leakage.
A vastin®, Lucentis®, Eyelea® Triescence®, and Kenalog® are among the growing list of drugs that are injected inside the eye to reduce blood vessel leakage under the retina. High dose antioxidants and zinc have been shown to slow the progression of certain stages of dry AMD. Since each case of AMD is different, the physicians at NRI are expert in using these treatment techniques to tailor a regimen best suited for each individual under their care.
If you have further questions, please feel free to ask any of the physicians at The National Retina Institute.