Cataract Surgery and Age-Related Macular Degeneration in the 2008-2012 Korea National Health and Nutrition Examination Survey

Park SJ, Lee JH, Ahn S, Park KH

JAMA Ophthalmol. 2016;134:621-626

Cataract Surgery Connection

Two of the most common causes of vision loss in the industrialized world are cataracts and age-related macular degeneration (AMD). For decades, it has been thought that cataract surgery may actually cause patients with macular degeneration to progress from early to late AMD, further compounding the vision loss they already experience. Studies have theorized that postoperative inflammation or intraoperative damage may result in disruptions in the Bruch membrane, in turn leading to neovascularization. However, cataract surgery continues to evolve and become more sophisticated, potentially diminishing this risk.

Study Summary

In this cross-sectional study, the authors had access to Korean Ophthalmological Society survey data from nearly 18,000 patients (34,863 eyes) over a span of 5 years. Participants underwent a health interview, examination, and nutrition surveys. All patients also had fundus photos, as well as documentation of lens status and other demographic and health metrics.

In the end, the authors examined 314 pseudophakic eyes with signs of AMD on fundus photos and 1691 phakic eyes with AMD. There was no difference between phakic and pseudophakic eyes when the incidences of early, late, and all stages of AMD were examined. The authors did, however, note a significant difference between the phakic and pseudophakic eyes when they separated the groups into right and left eyes: The left eyes with cataract surgery were more likely to have late AMD (defined as geographic atrophy or neovascular AMD). The left eye association could be attributed to chance, according to the authors.

The authors believed that focusing on a nationally representative population by using survey findings from a Korean database would eliminate the biases that prior studies neglected (ie, selection bias). In doing so, they felt their conclusion that there is no clear association between late AMD and pseudophakic status would be more acceptable. The authors hypothesized that recent surgical techniques leading to decreased intraocular inflammation and new lenses with increased ultraviolet-blocking technology account for the lack of an association between cataract surgery and AMD.

Viewpoint

This is a cross-sectional study and cannot assess progression of AMD, but instead only analyze its association with cataract surgery. It was done in a predominantly Asian population who probably have different variants of AMD, which may not react in the same manner as forms of AMD observed in other previously studied populations.

Although the numbers in this database are impressive, the authors examined only approximately 300 eyes with any AMD that had cataract surgery. This is a decent number of eyes, but significantly smaller than prior studies on this subject.

This study provides a succinct update on the issue of cataract surgery and AMD, with conclusions hinting that newer techniques in cataract surgery are not associated with late stages of AMD (or any stage of AMD, for that matter). However, it is not a longitudinal study and cannot assess causation. Moving forward, prospective studies using newer cataract surgical techniques would probably give an even clearer picture on whether or not cataract surgery using today's technology causes progression of AMD.