Cataract Surgery Does Not Worsen Age-Related Macular Degeneration

Fran Lowry

Cataract surgery does not appear to increase the progression of age-related macular degeneration (AMD). Instead, it might reveal pre-existing AMD that had been hidden by the cataract, suggests a new study published in the November issue of the Archives of Ophthalmology.

"There has been a longstanding controversy among clinicians as to whether cataract surgery is contraindicated in eyes with nonneovascular AMD," write Li Ming Dong, PhD, from Stony Brook University School of Medicine in New York, and associates from Johns Hopkins University School of Medicine in Baltimore, Maryland. "A major concern has been whether cataract surgery increases the risk of progression to neovascular AMD in eyes at risk of progression, such as those with intermediate AMD (extensive medium-sized drusen, large drusen, or nonfoveal geographic atrophy)."

The aim of this study was to evaluate the course of AMD during the year after cataract surgery in individuals with preconfirmed nonneovascular AMD.

The investigators analyzed 86 patients with nonneovascular AMD who underwent cataract surgery to note the incidence of neovascular AMD development in the 12 months after the operation. Only 1 eye from each patient was analyzed.

Fluorescein angiography was performed preoperatively, and at 1 week, 3 months, and 12 months postoperatively.

The median age of the patients was 76 years (range, 58 to 92 years); 48% were women, 97% were white, and nearly two thirds were current or former cigarette smokers. The median preoperative visual acuity (Snellen equivalent) was 20/50 (range, ≥20/40 to 20/400).

Photographic documentation of AMD status was done in 71 patients (83%) at the 12-month visit. Sixty-six patients (77%) also completed a clinical examination at this visit.

Neovascular AMD was observed in 9 eyes (12.7%; 95% confidence interval [CI], 6.0% - 22.7%) by 12 months, including 1 that was graded as probable neovascular AMD. Five eyes displayed signs of neovascular AMD at the 1-week follow-up, but the size and location of the lesions indicated that they might have been present before surgery but not visible because of the opacity caused by the cataract, the authors report.

One eye did not have a 1-week follow-up. After excluding this eye, as well as the 5 eyes that showed lesions at the first follow-up period, the rate of confirmed progression to neovascular AMD between week 1 and month 12 decreased to 3 (4.6%) of 65 eyes (95% CI, 1.0% - 12.9%), the investigators report.

The investigators also noted the progression to neovascular AMD in the study subjects' phakic contralateral eyes. They report that neovascular AMD developed in only 1 eye (3%) at 12 months.

Previous Reports Might Be Biased

"Our findings suggest that previous reports of the association or progression of nonneovascular AMD to advanced AMD after cataract surgery could be biased by the absence of immediate preoperative and postoperative fluorescein angiography to rule out pre-existing neovascular AMD or geographic atrophy," the study authors write, adding that a strength of their study — the first to their knowledge — was the use of color fundus photographs and fluorescein angiography in the immediate pre- and post-cataract surgery setting.

However, they point out, their study is limited by its small size and limited duration of follow-up to just 12 months. In addition 15 eyes (17%) at risk for neovascular AMD had to be excluded from the analysis because their postsurgery AMD status at 12 months could not be determined because of unavailable or ungradable images.

"Only a small percentage of study participants with AMD had definite progression to either neovascular AMD or geographic atrophy within 1 year of cataract surgery when eyes were carefully monitored with immediate preoperative and postoperative fundus photographs and fluorescein angiograms," the study authors conclude. "Our findings do not support the hypothesis that cataract surgery accelerates the progression of AMD."

In an accompanying editorial, Barbara E. K. Klein, MD, MPH, from the University of Wisconsin in Madison, writes that several reports have shown an association between cataract surgery and AMD since the late 1980s.

"Some report a cross-sectional association, some, incidence of AMD after surgery, and yet others report progression to more severe AMD. Still, there are some studies that do not find a significant association after controlling for relevant confounders. What might explain the disparate results? In my estimation, the diversity of findings in no small part begins with differences in study design," Dr. Klein noted."

Discussing these inconsistencies will help patients and their physicians make a more informed decision about the risks for progression to early AMD and development of late AMD after cataract surgery, she writes. "Until we have better information regarding the risk of developing AMD in those undergoing cataract surgery, it is the best we can do for our patients."

For more information go to www.maculardegenerationassociation.org