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Age-related macular degeneration (AMD) is a degenerative condition that affects the macula, the region in the center of the retina responsible for all central vision. AMD can produce rapid and severe vision loss1 and is the leading cause of blindness in people over 50 in the Western world.2 With AMD, patients experience loss of central vision in varying degrees, while retaining their side or peripheral vision.
The 2 Types of AMD
AMD is classified into 2 types: the “dry” (atrophic) form, marked by the appearance of small yellowish deposits known as “drusen” within the retina, and the more severe “wet” (neovascular) form.
Dry AMD
Dry AMD accounts for about 90% of AMD cases in the United States.3 In dry AMD, drusen accumulate in the retinal pigment epithelium (RPE), causing the macula to thin and dry out. Although this form of the disease usually only produces mild vision loss, patients may progress to wet AMD and, therefore, must be monitored continually.
Wet AMD
Among patients with any sign of AMD, estimates indicate that only about 10% to 20% have the wet form of the disease.3,4 Nonetheless, wet AMD is responsible for 90% of the severe vision loss associated with this condition.3,4 Approximately 200,000 new cases of wet AMD occur each year worldwide.5
Dry AMD
About 90% of people with AMD in United States have the dry form
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Wet AMD
Wet AMD occurs less often but is more aggressive in nature
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In wet AMD, choroidal neovascularization (CNV) occurs, in which abnormal choroidal blood vessels break through Bruch’s membrane into the subretinal space and retinal pigment epithelium. These weak and underdeveloped vessels leak blood and fluid into tissue under the retina, causing damage to the macula. As a result of this process, patients can experience 1) detachment of the RPE or neurosensory retina, 2) formation of a fibrovascular scar, and/or 3) vitreous hemorrhage (see below).6
Wet AMD Progresses Rapidly
The visual prognosis for most patients with wet AMD is poor. As shown by the Macular Photocoagulation Study (MPS), severe loss of vision can be rapid, with most vision loss occurring within the first 6 months of diagnosis.7
As visual acuity deteriorates, patients’ ability to perform certain daily tasks may be diminished severely.8,9
Although AMD tends to occur in one eye at a time, approximately 42% of patients who have wet AMD in one eye will also develop this condition in their second eye within 5 years. 10 Untreated, the majority of eyes affected with wet AMD will become functionally blind within 2 years of diagnosis. 11
Worldwide estimates indicate that by 2020 as many as 8 million persons aged more than 65 years could suffer from AMD.12 Although there is no known cure for AMD, there are proven treatments that have been shown to reduce the risk of severe vision loss.
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