Examining Absolute Risk of AMD in Relation to Cataract Surgery

Cataract surgery is a common procedure in older adults. It is becoming more common not only by virtue of increasing age of the population, but also because of trends in ophthalmic practice and higher prevalence and incidence of late age-related macular degeneration (AMD) in persons who have had cataract surgery as has previously been reported. In the study by Klein et al, the maximally adjusted odds ratio (OR) for incidence of late AMD after cataract surgery compared with eyes with ≥1 type of cataract was 1.96 (95% confidence interval, 1.28–3.02). Including the presence and severity of early AMD lesions in the model somewhat attenuated the overall OR; however, the effect of surgery remained significant (P<0.05). Knowledge of the approximate doubling of the odds of late AMD is of limited use when making recommendations or decisions in clinical practice because this does not place the increased odds in the context of the actual risk. In the current report, we have described the adjusted attributable risk (AR) estimate and number needed to harm (NNH) to provide a measure of absolute risk when evaluating the effect of cataract surgery on incidence of late AMD.