Macular Degeneration

Macular degeneration is an eye disease that usually strikes older adults. It is the leading cause of vision loss in the elderly.

The inside of the eye is lined with a light-sensitive membrane called the retina. The retina consists of specialized cells that detect colour and contrast. The macula is a small area at the centre of the retina responsible for central vision and fine detail vision. As its name implies, macular degeneration involves the deterioration of the macula. This leads to blurred central vision and can make certain activities such as reading and driving impossible. Although the disease can severely damage vision, it rarely leads to complete blindness since it does not affect peripheral vision (around the centre). Persons with macular degeneration could, for example, see the numbers on a clock, but would be unable to distinguish the hands.

Causes and triggers

There are two forms of macular degeneration:

Dry form

Dry macular degeneration is the most common form and accounts for the vast majority of cases. The loss of central vision is gradual and occurs over several years. It is characterized by the thinning of the macula.

Wet form

Less common, wet macular degeneration manifests as a sudden and severe loss of central vision. In this case, abnormal blood vessels develop under the macula. The vessels then leak fluid or blood when they rupture, hence the term 'wet'. This phenomenon creates a black spot or "blind spot" in the vision.

Macular degeneration is associated with the normal aging process. This means that any person over the age of 50 can be affected. Other risk factors include:

Symptoms

The symptoms associated with macular degeneration are limited to vision. Initially, the disease only affects one eye. This can delay diagnosis since the healthy eye generally compensates for the loss of vision in the affected eye. This can go on for several years before both eyes are finally affected. There is no pain associated with macular degeneration. The most common symptoms are:

• Blurred, washed out central vision
• Reduced colour perception
• Blind spot or black spot in the centre of the visual field
• Straight lines looking wavy or distorted (wet form)

Diagnosis

It is recommended that everyone aged 40 to 64 years old have an eye examination at least once every two years, and annually for those aged 65 and older. If detected early, it is possible to slow the progress of the disease and even stop it in the case of the wet form of the disease.

The Amsler Grid can be used alongside other tests to diagnose macular degeneration. It helps determine if straight lines appear distorted and if there is a blind spot or black spots in the vision field. This test can also be used for at-home follow-up purposes.

Treatment

There is currently no treatment available to restore lost vision. In the early stage of the disease, its progression can be slowed by simply reducing the risk factors: maintain a healthy diet, rich in antioxidants and omega-3s, control blood pressure, and quit smoking. You have to continue monitoring your vision and report any changes to your eye care professional. Medications may be taken to slow the progress of macular degeneration, as well as certain vitamins and minerals. Additionally, laser surgery can stop the progression of wet macular degeneration. In all cases, be aware that there are organizations that help people with macular degeneration maintain their autonomy.

For more information or for support:

• See the possibilities (Canadian Ophthalmological Society)
• Canada: Canadian National Institute for the Blind (CNIB)
  The CNIB does not currently offer all services in Quebec.
• Quebec: The Quebec Foundation for the Blind