MONDAY, Nov. 9, 2009 (HealthDay News) -- Cataract surgery doesn't appear to speed the progression of age-related macular degeneration (AMD), according to a new study that challenges the belief that treating one cause of vision loss worsens the other.
"Because both conditions are strongly age-related, many individuals with cataract also have AMD," wrote Li Ming Dong, of Stony Brook University School of Medicine in New York, and colleagues. "There has been a long-standing controversy among clinicians as to whether cataract surgery is contraindicated in eyes with non-neovascular AMD. A major concern has been whether cataract surgery increases the risk of progression to neovascular AMD (an advanced form of the disease involving formation of new blood vessels) in eyes at risk of progression such as those with intermediate AMD."
In this study, the researchers examined 71 eyes of patients with non-neovascular AMD before, and at one week and one year after they had cataract surgery. After one week of follow-up, five eyes showed signs of neovascular AMD. But the researchers said the size and location of the neovascular AMD lesions suggest they may have been present before surgery but couldn't be detected due to the opaque eye lens caused by cataract.
When these eyes were excluded, progression to neovascular AMD occurred in 4.6 percent of the eyes between one week and one year after cataract surgery, compared with 3 percent for cataract-free eyes.
"Our findings suggest that previous reports of the association or progression of non-neovascular AMD to advanced AMD after cataract surgery could be biased," the researchers wrote.
"Subtle signs of neovascular AMD or geographic atrophy, even on an angiogram, may be obscured by lens opacity just prior to cataract surgery," the team explain. "In such cases, the neovascular disease or the geographic atrophy may contribute to the individual's vision loss, and this may erroneously be ascribed to the cataract and contribute to a decision to proceed with cataract surgery."
Dong's team concluded: "Our findings do not support the hypothesis that cataract surgery accelerates the progression of AMD."
The study results are published in the November issue of the journal Archives of Ophthalmology.
The U.S. National Eye Institute has more about age-related macular degeneration.