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Macular Degeneration
The Macula
The macula is the area of the retina that gives sharp central vision. In macular degeneration, the light sensing cells of the macula are affected.
What is macular degeneration?
Macular degeneration occurs most often in people over 60 years of age, in which case it is called age-related macular degeneration. When the macula loses its ability to function, one experiences blurriness or distortion in the center of vision. This makes close and detailed work, such as reading or threading a needle, difficult even with glasses. Reading glasses may help to a limited degree, but in more advanced macular degeneration, one may require special aides.
Although macular degeneration reduces central vision, it does not affect the eye's peripheral vision, which is the ability to see objects to the side of the center. This means macular degeneration will not result in complete blindness.
The majority of people with macular degeneration (85-90%) have the DRY form, in which waste deposits called drusen collect under the retina in the macula. The dry form of macular degeneration, in general, causes only a gradual change of vision over many years.
A minority of people with macular degeneration (10-15%), have the WET form of macular degeneration, which results from leakage of blood under the retina in the macula. This can cause a sudden change, consisting of a rapid onset of decreased central vision with distortion.
Treatment for macular degeneration
Despite ongoing medical research, there is no "cure" for the dry form of macular degeneration. Studies are being conducted regarding the value of nutritional supplements to delay progression. Diets high in leafy green vegetables have been associated with decreased rates of progression of macular degeneration. Smokers have an increased rate of progression.
Recent evidence shows that dietary vitamin supplements may also delay progression of dry macular degeneration, specifically daily oral tablets containing vitamin C 500mg, vitamin E 400 IU, Lutein 10 mg, 80mg zinc, Zeaxanthin 2 mg, and 2mg copper. There are some commercially available multivitamins that attempt to match this combination and dosage of supplements (eg: Vitalux, PreserVision, Ocuvite, or any other AREDS based supplements).
People with the less common wet form of macular degeneration may benefit from administration of a specific drug into the eye, photodynamic therapy or laser, all of which close leaking blood vessels. All of these treatments are carried out by retina sub-specialists, and require an initial evaluation including a test called fluorescein angiography to determine if they are an option.
Testing your vision with the Amsler Grid:
In order to detect even small changes in your vision, your ophthalmologist may recommend that you check your vision on a routine basis by using an Amsler grid.
To use the grid:
1. Wear your reading glasses and hold this grid at 12-15 inches, in good light.
2. Cover one eye.
3. Look directly at the center dot with the uncovered eye.
4. While looking directly at the center dot, note whether all lines of the grid are straight, or if any areas are distorted, blurred, or dark.
5. Repeat this procedure with the other eye.
6. If any area of the grid looks distorted, blurred, dark, discoloured, or otherwise abnormal (that were previously normal), contact your ophthalmologist immediately. |
