One of the most common causes of poor vision after the age of 60 is age-related macular degeneration (AMD). Current estimates put the incidence of AMD at 10 percent in patients age 64 to 75 and 30 percent in patients over 75 years of age. In addition to age, certain risk factors have been determined including blue eyes, heredity, high blood pressure, cardiovascular disease, and smoking. AMD affects the macula, the part of the retina that is responsible for central and detailed vision, resulting in a loss of central vision and visual acuity. There are two forms of AMD: the dry form, which is more common, and the wet form. There is no treatment for dry AMD, but laser therapy has been shown to effectively treat wet AMD.
Detecting Macular Degeneration
There are a number of signs and symptoms that indicate the onset of macular degeneration. The formation of drusen, yellow deposits around the macula, is a good early indicator of developing macular degeneration. Other common signs include pigmentary alterations in the eye, unusual fluids exuded from the eye, and atrophy. Sudden, drastic decreases in visual acuity are a common warning sign. Loss of detailed vision, particularly central vision, is a classic symptom of macular degeneration. The Amsler Grid Test is a popular and effective ophthalmological test your eye doctor can perform to help diagnose macular degeneration. The Amsler Grid is simply a grid of vertical and horizontal lines with a dot in the center for focusing reference. A patient suffering from macular degeneration will see the grid as distorted, and parts of the grid may seem completely blank.
Two types of Macular Degeneration
Dry AMD: This form is quite common. About 90% (9 out 10) people who have AMD have the dry form. Dry AMD is when parts of the macula get thinner with age and drusen grow. You slowly lose central vision. There is no way to treat dry AMD yet.
Wet AMD: This form is less common but much more serious. Wet AMD is when new, abnormal blood vessels grow under the retina. These vessels may leak blood or other fluids, causing scarring of the macula. You lose vision faster with wet AMD then with dry AMD.
Many people don’t realize they have AMD until their vision is very blurry. It is important to have regular visits to an ophthalmologist.
Who is at risk for getting AMD?
You are more likely to develop AMD if you:
- Smoke cigarettes
- Are over 50 years of age
- Have a family history of AMD
- Are Caucasian (white)