You may have heard of an eye condition known as age-related macular degeneration (ARMD or AMD). Maybe you’ve had a parent or grandparent diagnosed with ARMD, or if you are of sufficient age, perhaps your own eye doctor has mentioned it to you. Macular degeneration is a medical condition which affects the macula, the part of the retina responsible for vision in the center of the visual field. Generally associated with aging, macular degeneration can be found in approximately 10% of people between the ages of 66 and 74, and 30% of those between the ages of 75 and 85. While macular degeneration does not cause total blindness, the loss of central vision can make everyday activities, such as recognizing faces and reading, difficult or even impossible.

 

Age-related macular degeneration can be classified into two forms: exudative, also referred to as “wet” macular degeneration; and non-exudative, also known as “dry” macular degeneration. While both forms of ARMD have similar outcomes – loss of central vision – they are quite different in their causes and treatment options.

 

The Types of ARMD, and How They are Treated

Dry macular degeneration is by far the more common of the two types of ARMD, accounting for approximately 90% of all cases. It occurs when cellular debris, known as drusen, accumulates between the choroid and the retina, causing the retina to detach. While there is no way to cure dry macular degeneration or reverse its effects, the National Eye Institute has suggested that vitamin supplements with high doses of antioxidants such as lutein and zeaxanthin may help prevent or delay its onset and progression. There are currently many multivitamins available over-the-counter that have been formulated to help slow or prevent ARMD, such as Ocuvite and iCaps.

Wet macular degeneration occurs when there is abnormal growth of blood vessels, known as choroidal neovascularization, below the macula. These abnormal blood vessels can leak blood and protein behind the retina, causing detachment. Compared to dry macular degeneration, the wet form can advance very quickly, causing rapid, permanent central vision loss. However, unlike dry AMD, the wet form is directly treatable. The most common treatment for wet AMD is injection, directly into the eye, of drugs that can cause the abnormal blood vessels to regress. Another treatment option is laser treatment, where a special drug (verteporfin) is administered intravenously. Laser light is then applied to the abnormal blood vessels, activating the drug and destroying the vessels.

Detection and Prevention

In the case of dry as well as wet macular degeneration, the key to maintaining best possible vision is early detection. Both forms of ARMD can be detected by a comprehensive eye exam. A simple Amsler Grid test, where a patient looks at a square grid of straight lines, can detect ARMD-related vision loss.

Left: Amsler grid as seen by normal eye; Right: Amsler grid distorted by ARMD

Optical coherence tomography (OCT), a 3-D image of the retina, is another excellent tool for diagnosing ARMD. Once ARMD has been detected, treatment (in the case of wet AMD), or supplementation (in the case of dry AMD) can begin. This is another great reason to have an annual eye examination performed by a qualified eye doctor.

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