Macular Degeneration

he human eye is designed to perceive and process a "panoramic" view, allowing you to see things both straight ahead and off to the side. Light entering your eye is focused by the lens onto the retina. The central part of that focused light falls on the macula, and which converts the light into the central and sharpest images of your vision. The light that falls to the sides of the macula are images seen "out of the corner of your eye." The macula is made up of three layers: cones (which perceive the light and color, and shed their tips daily), pigment epithelium (which supports and nourished the cones, and "digests" the cone tips to prevent them from accumulating) and the choroid (which transports nourishment to, and wastes away from, the epithelium).

With time and use, the macula degenerates -- however, it is never caused by overusing your eyes. The result is vision loss, either gradually or abruptly in the central part of your vision, usually affecting both eyes. Side vision is unaffected, thus macular degeneration rarely leads to total blindness.

Macular degeneration is the leading cause of vision loss in people over 65 years of age, though the disease can affect younger people. It is more common among older, light-haired, fair-skinned people. Symptoms include: difficulty reading road signs where there was no such difficulty before; distorted appearance of letters you are trying to read; dark spot in the center of your vision; straight objects appearing crooked or distorted.

In general, this type of vision loss falls into two categories: dry-type, with gradual vision loss, or wet-type with sudden vision loss.

Dry type
    caused by the formation of drüsen, or the accumulated material from the shed cone cells that cannot be processed or "digested" by the pigment epithelium. Parts of the macula may stop functioning, leaving blank spots and wavy lines in your vision.

Wet type
    build-up of fluid due to the growth of new blood vessels under the pigment epithelium, which leak fluid or blood, causing the macular to bulge. Vision is distorted, and straight lines may look curved or wavy, accompanied by a dark spot in the center of your vision.

To some extent, you can protect your eyesight with filters on your glasses; your doctor may make specific dietary suggestions. An Amsler grid enables you to check your eyes at home.

Laser treatment is possible for wet-type macular degeneration. The laser dries up leaking blood vessels and prevents them from growing further. As leakage can occur more than once, and more than one treatment may be required.

Procedure
The whole procedure normally lasts about 15 minutes. Your pupils are dilated with eyedrops, and your eye anesthetized. Holding a contact lens against your eye, light is focused into your eye. The procedure is usually painless, though you will see flashes of light.

There is a slight risk of bleeding, but this is easily halted. Also, since some healthy tissue is destroyed, a "blind spot" is likely to develop. However, studies show that vision loss is greater for those patients who do not undergo laser treatment for wet macular degeneration.

After the Procedure
Immediately following laser treatment, you are likely to have increased blurring, which improves over several weeks. Daily Amsler grid checks are recommended, and frequent follow-up visits are required to stem new blood vessels from growing.