February 5 (HealthDay News) -- Cataract surgery doesn't hasten vision loss in people with age-related macular degeneration (AMD).

That's the conclusion of a new study that challenges the findings of several large epidemiological studies that suggested a link between cataract surgery and accelerated AMD progression.

AMD and cataracts are leading causes of vision impairment in the United States. Both are related to aging and share other risk factors. AMD affects the retina and leads to loss of central vision. Cataract is cloudiness in the eye's lens that interferes with clear vision.

For the new study, Dr. Emily Y. Chew, of the U.S. National Eye Institute, and colleagues analyzed data from 4,577 participants (8,050 eyes), ages 55 to 81, who took part in the Age-Related Eye Disease Study (AREDS). The researchers compared the risk of advanced age-related macular degeneration in people who had surgery to remove cataracts and in those who didn't have the surgery.

Chew and her team found little evidence that cataract surgery influences AMD progression. The study was published in the February issue of the journal Ophthalmology.

"These data may provide some reassurance to patients with AMD who are considering cataract surgery," Chew said in an American Academy of Ophthalmology news release.

Several possible factors may explain the conflicting conclusions of this new study and previous population-based research, Chew said. The most likely factor is that earlier studies may have had unintended biases or confounding variables. Chew also noted that cataract surgery and lens replacement techniques have advanced, and the AREDS participants' procedures were performed more recently than people included in earlier studies.

SOURCE: American Academy of Ophthalmology, news release, Feb. 2, 2009