General Information About Macular Degeneration
What is macular degeneration?
Macular degeneration is the most common cause of severe vision loss in Canada, especially among the elderly. It causes 1 in 3 cases of reported vision loss. The most common form of the disease occurs in people over age 55 and is called “age-related macular degeneration.”
At the back of the eye there is a thin layer of lightsensitive tissue called the retina. The eye focuses light onto a small spot about the size of a pea called the macula. The macula processes the details in the central part of our vision, and is responsible for us being able to see the finest details, colours and to function in daylight.
If the macula is diseased for any reason, the retina becomes like a camera with a spot on the film in the centre of the picture. This results in blurry central vision and loss of details.
There are two types of macular degeneration. In the “dry” type, the central part of the retina becomes distorted, or pigmented or thinned. Symptoms of central visual loss develop slowly and almost unnoticeably.
In the more severe “wet” type, abnormal blood vessels develop and leak fluid and blood under the macula and into the retina. When the blood and fluid dry, a scar is left in the macula, which creates a black spot in your field of vision. Symptoms of the wet type can develop quickly and cause severe loss of vision.
What causes macular degeneration?
We do not know all of the causes of macular degeneration. Age-related macular degeneration seems to be a “sped-up” and severe form of aging of the retina and the tissues around it. Although the wet type is usually associated with aging, it may be linked to other conditions, such as infections, high blood pressure, hardening of the arteries, and diabetes. Children and teenagers may inherit macular degeneration from their parents. Extreme nearsightedness is also a factor. Toxic light damage (like a solar or eclipse burn) or a traumatic eye injury that detaches the retina from the back of the eye may also damage the macula.
How is macular degeneration diagnosed?
Although macular degeneration may develop slowly or quickly, it usually occurs gradually over a few years. Side (peripheral) vision will most likely stay normal, but you will find it hard to see at a distance or up close. Faces may begin to blur, and colours may be hard to distinguish. You may see distortions or wavy lines.
If you have new-onset blurred or distorted central vision, see a medical doctor or your eye doctor right away. He or she will refer you to an ophthalmologist. Everyone over age 45 should have regular eye exams by a qualified eye care professional.
The best way to detect early wet macular degeneration is with OCT.
How is macular degeneration treated?
It may be possible to significantly delay visual loss with moderately advanced dry age-related macular degeneration by taking a combination of vitamin C, vitamin E, beta-carotene and zinc. Several supplement brands containing the correct dosages are available and can be purchased without prescription. Your ophthalmologist can tell you whether this treatment is right for you.
There is no treatment for dry macular degeneration.
The new standard of care for wet macular degeneration is monthly Lucentis injections. This special drug (now covered by OHIP) will help stop further progression of the wet macular degeneration. View Dr. Lane performing a Lucentis injection
While people with macular degeneration almost never go completely blind, visual loss from the disease is rarely reversed. However, you can usually continue most of your activities of daily living by using your side(peripheral) vision and by learning to look around the central blurry patch in your vision. Vision rehabilitation is also available to help you make the most of your remaining vision. Vision rehabilitation clinics are available across the country in eye care centres and through the CNIB.
Ophthalmologist: A medically trained eye doctor and surgeon.
Retina: Thin, light-sensitive tissue that covers the back of the eye and works like film in a camera to register the images we see.
Information Courtesy of:
Canadian Ophthalmological Society
1525 Carling Avenue, Suite 610
Ottawa, Ontario Canada K1Z 8R9