All medical content reviewed by our Drug Safety Associate Patience Biesiot, RN, BSN.
Age Related Macular Degeneration (AMD) is one of the leading causes of vision loss in Americans 50 and older, and affects more than 10 million Americans today. Some estimates (although from 2009) expect the total number to double by the year 2050 due to the aging U.S. population.
AMD and low vision go hand in hand, unfortunately.
Because AMD directly impacts the macula, those effected begin to lose central vision—often in the form of decreasingly clear sight, which can progress to dark, splotchy areas in the center of your vision.
This slow-moving sight thief occurs in two forms: dry and wet.
Macular.org provides the following descriptions:
Dry Macular Degeneration
“About 90 percent of all people with Age-related Macular Degeneration have “dry” AMD, a condition in which layers of the macula (including the photoreceptors and the retinal pigment epithelium) get progressively thinner, functioning less and less as they do. This is called atrophy. In the early stage of dry AMD, the pigment or color of the macula changes. Tiny drusen appear on the retina: these are little piles of waste product of the cells of the eye. Drusen themselves may lead to deterioration and atrophy of the retina. Dry AMD often does not progress further than pigment discoloration and the presence of drusen. In fact, nearly everyone over 50 years of age has at least one small drusen.
Dry AMD is also called non-neovascular AMD and non-exudative AMD because it does not involve the exuding – that is, leakage – of fluids from blood vessels. Advanced cases – “late dry” AMD – are called geographic atrophy (GA) because large sections of the retina that are well demarcated (geographies) stop functioning.”
Wet Macular Degeneration
“About ten percent of all cases of Age-related Macular Degeneration become “Wet” AMD (typically a person has dry AMD first and progresses toward wet). Wet AMD is a condition in which new blood vessels grow in the choroid layer behind the retina. This condition is called choroidal neovascularization or CNV. The new vessels are weak, and they leak fluid, lipids (part of the structure of cells), and blood. The leaking gets into the layers of the retina – including the layers of the macula – and can cause scar tissue to form and retinal cells to stop functioning.
Wet AMD is also called neovascular AMD or exudative AMD because it involves the exudation or leakage of fluid and blood from new blood vessels.”
Stages of AMD
Macular.org provides the following definitions for the three stages of AMD:
Early AMD – Most people do not experience vision loss in the early stage of AMD, which is why regular eye exams are important, particularly if you have more than one risk factor (see below). Early AMD is diagnosed by the presence of medium-sized drusen (yellow deposits beneath the retina).
Intermediate AMD – At this stage, there may be some vision loss, but there still may not be noticeable symptoms. A comprehensive eye exam with specific tests will look for larger drusen and/or pigment changes in the retina.
Late AMD – At this stage, vision loss has become noticeable.
What Does Vision With AMD Look Like?
To get an idea of what AMD might look like, take a look at this short video produced by the National Eye Institute:
With February being declared AMD/low vision awareness month, make sure to maintain or establish a routine for visiting your eye care professional. Normally, it’s recommended that individuals should have a comprehensive eye exam every one or two years. Some individuals may benefit from more frequent visits.
Always visit your eye specialist if any changes to your vision occur.