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ESSENTIALS OF DIAGNOSIS
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ESSENTIALS OF DIAGNOSIS
Older age group.
In one or both eyes; acute or chronic deterioration of central vision; distortion or abnormal size of images, sometimes developing acutely.
No pain or redness.
Classified as dry (“atrophic,” “geographic”) or wet (“neovascular,” “exudative”) macular degeneration.
Macular abnormalities seen by ophthalmoscopy.
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GENERAL CONSIDERATIONS
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Age-related macular degeneration is the leading cause of permanent visual loss in the older population. Its prevalence progressively increases over age 50 years (to almost 30% by age 75). Its occurrence and response to treatment are likely influenced by genetically determined variations, many of which involve the complement pathway. Other associated factors are sex (slight female predominance), family history, hypertension, hypercholesterolemia, cardiovascular disease, farsightedness, light iris color, and cigarette smoking (the most readily modifiable risk factor).
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Although both dry and wet age-related macular degeneration are progressive and usually bilateral, they differ in manifestations, prognosis, and management.
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Drusen are the hallmark of age-related macular degeneration (eFigure 7–43). Hard drusen appear ophthalmoscopically as discrete yellow subretinal deposits. Soft drusen are paler and less distinct. Large, confluent soft drusen are risk factors for neovascular (wet) age-related macular degeneration. Vision loss in age-related macular degeneration involves the central vision only in most patients. Peripheral fields, and hence navigational vision, are maintained, except in patients with severe neovascular age-related macular degeneration.
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“Dry” age-related macular degeneration is characterized by gradually progressive bilateral visual loss due to geographic atrophy of the outer retina, the retinal pigment epithelium, and the choriocapillaris, which supplies blood to both the outer retina and the retinal pigment epithelium (eFigure 7–44) (eFigure 7–45). In “wet” age-related macular degeneration, choroidal new vessels grow under either the retina or the retinal pigment epithelial cells, leading to accumulation of exudative fluid, hemorrhage, and fibrosis (eFigure 7–46). The onset of visual loss is more rapid and more severe than in atrophic degeneration. The two eyes are frequently affected sequentially over a period of a few years. Although “dry” age-related macular degeneration is much more common, untreated “wet” age-related macular degeneration accounts for about 90% of all cases of legal blindness due to age-related macular degeneration.
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