Age-related macular degeneration (AMD) is the leading cause of
irreversible vision loss in the developed world. In 2004, AMD
affected 1.75 million persons in the United States, a number which
is expected to rise to nearly 3 million by 2020 due to the aging of
the population. AMD is characterized by the appearance of
involutional changes (e.g. drusen) in the structure of the central
retinal pigment epithelium (RPE) leading to the loss of normal
central (macular) vision. AMD can be categorized as dry
(non-exudative) or wet (exudative). Dry AMD represents the great
majority of AMD patients (90%) and may lead to slow visual loss
over many decades, with the most severe cases developing geographic
atrophy and profound loss of central vision. Dry AMD can progress
to wet AMD with the development of neovascularization beneath the
diseased RPE leading to hemorrhage, scarring, and the devastating
loss of macular vision over a period of months. By convention,
there are four categories which describe the severity of macular
degeneration. Category 1 are those patients essentially free of
age-related macular abnormalities, with a total drusen area less
than five small drusen (63 m), and visual acuity of 20/32 or better
in both eyes. Category 2 patients have mild or borderline,
age-related macular features (multiple small drusen, single or
nonextensive intermediate drusen (63-124 m), pigment abnormalities,
or any combination of these) in one or both eyes, and visual acuity
of 20/32 or better in both eyes. Category 3 patients require the
absence of advanced AMD in both eyes and at least one eye with
visual acuity of 20/32 or better with at least one large drusen
(125 m), extensive (as measured by drusen area) intermediate
drusen, or geographic atrophy (GA) that does not involve the center
of the macula, or any combination of these. Category 4 patients
have visual acuity of 20/32 or better and no advanced AMD in one
eye, with the fellow eye having either lesions of advanced AMD, or
visual acuity less than 20/32 with AMD abnormalities sufficient to
explain reduced visual acuity as determined by examination of
photographs. Advanced AMD is defined as having GA involving the
center of the macula or features of choroidal neovascularization.
Observational studies suggest that people with dietary intakes
higher in various carotenoids, antioxidants and omega-3 fatty acids
have a lower risk of developing AMD. This has led to several
supplementation trials designed to examine the ability of
nutritional supplement with carotenoids, antioxidants, or omega-3
fatty acids to prevent the progression of AMD. Our report focuses
on the evidence documenting the potential benefits and harms of
certain dietary supplements in patients with AMD. Recommendations
to the Department of Veterans Affairs with regard to these
supplements will have important implications to that patient
population as well as to older U.S. adults. We conducted a
systematic review of published literature to address the following
key questions:1) In patients with age-related macular degeneration,
do nutritional supplements containing carotenoids, antioxidants, or
omega-3 fatty acids alone or in combination prevent functional
visual loss? 2) In adult populations, what are the harms of
carotenoid, antioxidant, and omega-3 fatty acid supplementation?
|Country of origin:
U S Department of Veterans Affairs
• Health Services Research & Deve Service
||280 x 216 x 3mm (L x W x T)
||Paperback - Trade
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