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Age-related macular degeneration (AMD or ARMD) is a condition associated with central vision loss, which affects one’s ability to read, drive, or see someone’s face if it progresses to more advanced stages. It is a common condition among people age 50 years and older.
The macula refers to the central portion of the retina. The retina is similar to film inside a camera. The image one sees is focused by the cornea and lens of the eye onto the center of the retina (macula.) Many people with age-related macular degeneration have minimal visual symptoms and may retain good vision their whole lives. A relatively small percentage of people with AMD will lose central vision, which may impair their ability to read and drive a car.
Two major types of AMD are “dry” (non-neovascular) and “wet” (neovascular) form.
Causes and Associations
AMD is a complex, degenerative condition that becomes increasingly prevalent with advanced age. It is typically found in people ages 50 years or more, although drusen sometimes can be seen in younger people. Family history is another important association, although simply having a blood relative with AMD does not necessarily mean or guarantee that one will definitely develop AMD. Risk factors for AMD can be controlled.
In order to prevent or slow the progression of macular degeneration: stop smoking, have a good nutritional intake, and controlling high blood pressure.
Genetics and Macular Degeneration
In addition to the aforementioned associations, genetics play a key role in AMD, with heredity representing over 70% of the risk of developing the disease. Genetic markers have recently been identified that strongly influence the risk of progression to advanced AMD with vision loss. Several of these gene variants promote inflammation by altering activation of the complement cascade, which is an active part of our immune system. Other gene variants affect mitochondrial function and increase oxidative stress in the retina, consistent with both the role of smoking as a risk factor and the benefit of antioxidants in delaying disease progression. Cholesterol metabolizing enzyme variants are also associated with this disease, consistent with the known biochemical composition of drusen.
Early identification of higher-risk patients may help prevent vision loss or slow down disease progression. Environmental risk factors can be identified, lifestyle modifications can be made, and nutritional supplementation can be instituted in these situations to further reduce the risk of disease progression. Frequent monitoring of these individuals may result in early detection of wet AMD, leading to better visual outcomes through earlier macular degeneration treatment.
Symptoms of Macular Degeneration
Many people with mild dry AMD have little to no visual symptoms. Some people, however, will require more light to read, have difficulty adjusting between dark and light conditions, or notice mild blurring of vision. Occasionally, a significant loss of central vision can occur. Vision loss associated with dry AMD is usually gradual or slow. Because AMD affects the macula, the symptoms are typically related to central vision tasks such as reading or driving. Peripheral vision is typically not affected.
Those with wet AMD often have more rapidly progressive loss of central vision, typically over days to weeks. Visual distortion is a common symptom of this stage. Occasionally, however, people may not be aware of these visual changes because their other eye sees well. Therefore, it is important to test the vision in each eye separately by covering one eye at a time when checking vision.
Amsler Grid Chart Test
An Amsler grid is a self-monitoring tool that allows people to check their vision one eye at a time to monitor for blurring or distortion that may signify the conversion from dry to wet AMD. People with AMD progression may notice changes on the Amsler grid, and if this occurs, they should contact their ophthalmologist promptly. The Amsler grid chart should be used to check the central part of your visual field, the area that can be damaged by macular degeneration.
Instructions for Use:
If you have any signs or symptoms of macular degeneration, contact us today to meet with a Mid Atlantic Retina specialist. While there is currently no cure for AMD, our team can work with you to protect your vision and minimize your complications.