What is age-related macular degeneration (AMD)?
Age-related macular degeneration (or AMD) is an eye disease that causes people to lose the central part of their vision as they age. People with AMD have difficulty seeing things directly in front of them, although their side vision may be fine.
The back of the eye is lined by a delicate layer of cells called the retina. Cells in this area called photoreceptors gather light and allow us to see. The most central part of the retina is called the macula. It contains the photoreceptors needed for straight-ahead vision and for seeing fine details and colour. In people with AMD, the photoreceptors in this part of the eye are damaged, and the person begins to lose the central part of their vision, which may appear dark, blurred or distorted.
As its name indicates, AMD is more likely to affect people in their senior years. It is the leading cause of legal blindness in Canadians over the age of 60 and is most common in people over age 75. According to the CNIB, an estimated one million Canadians already have some form of AMD – although many only have mild vision loss. Because our population is aging, this number is expected to double by 2031.
There are two basic types of AMD: "wet" and "dry".
Dry AMD (sometimes called atrophic AMD) is the most common type accounting for 90% of all cases. It causes a slow progressive loss of central vision. In people with dry AMD, the macula slowly gets thinner and yellowish deposits called drusen build up. These deposits are visible when an eye doctor examines the eye. The most severe form of dry AMD is called geographic atrophy. In people with geographic atrophy, many of the photoreceptors in the macula have died, and people with this condition lose most of their central vision. .
Wet AMD (sometimes called exudative AMD) occurs when abnormal blood vessels grow under the macula which becomes extremely thin, a condition called choroidal neovascularization (CNV). These vessels may leak blood and fluid causing severe and rapid vision loss. Because of this risk, it is important for people with wet AMD to be seen quickly and treated as appropriate. Although only about 10% of people with AMD will develop wet AMD, this is the most serious form of the disease accounting for about 90% of the cases of severe vision loss due to AMD.
We do not understand exactly why AMD develops – but a number of factors that put people at risk have been identified. In 2009, Dr. Gilbert Bernier, a scientist funded by the FFB to conduct research at the Maisonneuve-Rosemont Hospital in Montreal discovered that mutations in a gene called Bmi1 caused rapid aging in the eyes and brains of mice. Discoveries like this may one day help us understand and treat AMD and other diseases of aging such as Alzheimer’s and Parkinson’s..
Learn more about some of the research on AMD currently being supported by your donations to the Foundation Fighting Blindness. Use this link to donate online.
The back of the eye is lined by a delicate layer of cells called the retina. Cells in this area called photoreceptors gather light and allow us to see. The most central part of the retina is called the macula. It contains the photoreceptors needed for straight-ahead vision and for seeing fine details and colour. In people with AMD, the photoreceptors in this part of the eye are damaged, and the person begins to lose the central part of their vision, which may appear dark, blurred or distorted.
As its name indicates, AMD is more likely to affect people in their senior years. It is the leading cause of legal blindness in Canadians over the age of 60 and is most common in people over age 75. According to the CNIB, an estimated one million Canadians already have some form of AMD – although many only have mild vision loss. Because our population is aging, this number is expected to double by 2031.
There are two basic types of AMD: "wet" and "dry".
Dry AMD (sometimes called atrophic AMD) is the most common type accounting for 90% of all cases. It causes a slow progressive loss of central vision. In people with dry AMD, the macula slowly gets thinner and yellowish deposits called drusen build up. These deposits are visible when an eye doctor examines the eye. The most severe form of dry AMD is called geographic atrophy. In people with geographic atrophy, many of the photoreceptors in the macula have died, and people with this condition lose most of their central vision. .
Wet AMD (sometimes called exudative AMD) occurs when abnormal blood vessels grow under the macula which becomes extremely thin, a condition called choroidal neovascularization (CNV). These vessels may leak blood and fluid causing severe and rapid vision loss. Because of this risk, it is important for people with wet AMD to be seen quickly and treated as appropriate. Although only about 10% of people with AMD will develop wet AMD, this is the most serious form of the disease accounting for about 90% of the cases of severe vision loss due to AMD.
We do not understand exactly why AMD develops – but a number of factors that put people at risk have been identified. In 2009, Dr. Gilbert Bernier, a scientist funded by the FFB to conduct research at the Maisonneuve-Rosemont Hospital in Montreal discovered that mutations in a gene called Bmi1 caused rapid aging in the eyes and brains of mice. Discoveries like this may one day help us understand and treat AMD and other diseases of aging such as Alzheimer’s and Parkinson’s..
Learn more about some of the research on AMD currently being supported by your donations to the Foundation Fighting Blindness. Use this link to donate online.
Updated: September 15, 2010. This section has been reviewed by Dr. Peter Kertes, Associate Professor of Ophthalmology and Vision Sciences at the University of Toronto and Dr. William Stell, FFB Director of Research Programs and Professor of Ophthalmology at the University of Calgary.
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| Risk Factors for AMD | AMD Prevention |
| Early Detection | AMD Treatment |
| AMD Research | Frequently Asked Questions |