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Freeman, Cataract Surgery and Age-Related Macular Degeneration
INTRODUCTION
The most common cause of vision loss in the elderly in the United States is age-related
cataract,
1-2
whereas the most common cause of blindness in this group is age-related macular
degeneration (AMD)
3-4
. The visual prognosis for patients with cataract is very good. In fact,
96% have improved visual acuity 4 months after surgery
5
. In contrast, the prognosis for patients
with AMD is less optimistic, as there is only proven treatment for the less common neovascular
form.
Cataract surgery is the most common procedure performed in the Medicare population,
with over 1 million cataract surgeries performed per year in the United States
6
. Several large
epidemiological studies have assessed the question of a possible association between cataract
surgery and late AMD
7-10
. The Beaver Dam Eye Study, a population-based prospective study of
3,684 adults ages 40 and older, found that those individuals who had previous cataract surgery
had a higher 10-year risk of developing incident late age-related maculopathy (OR=3.8, 95% CI
1.9-7.7)
8
. However, the Blue Mountain Eye Study, a population-based survey of 3,654 adults
ages 49 and older, did not find an association
9
. In addition, the Visual Impairment project did
not find an association between cataract surgery and late AMD after adjusting for other
variables.
10
Some studies have found an association between the presence of a lens opacity in the eye
and late AMD, suggesting that cataract and late AMD may share one or more common risk
factors
7,11
. Why cataract surgery and late AMD may be associated is still unknown, although
some have suggested that surgery may increase the risk of late AMD in susceptible eyes
11, 12
.
Therefore, to evaluate whether cataract surgery and late AMD were associated, we
examined existing data from three independent, population-based studies in order to maximize
the number of individuals with late AMD.
