Cataract Surgery and the Risk of Conversion from Dry to Neovascular Age-related Macular Degeneration in the IRIS© Registry

Objective To evaluate the association between cataract surgery (CS) and risk of conversion from dry age-related macular degeneration (dAMD) to neovascular AMD (nvAMD), and to identify factors associated with conversion. Design Population-based retrospective time-to-event study Subjects Patients aged ≥55 years with early or intermediate dAMD and phakic status at baseline. Eyes with a history of CS, a prior diagnosis of nvAMD, or prior anti–vascular endothelial growth factor (anti-VEGF) therapy before cohort entry were excluded. Eyes that underwent CS were classified as exposed; those without CS during the study period were nonexposed. Methods Eyes were propensity score matched 1:1 on age, sex, race, and ethnicity, laterality, AMD stage, and smoking status. CS was modeled as a time-varying exposure. We used Cox proportional hazards regression to estimate the hazard of conversion to nvAMD over the 7-year study period. Main Outcome Measures Conversion from dAMD to nvAMD between exposed and nonexposed cohorts Results After matching, 40,053 eyes were included in each exposed and nonexposed cohort (total N = 80,106 eyes). CS was associated with a higher risk of nvAMD conversion (hazard ratio [HR] = 1.22; 95% CI, 1.16–1.30; P < 0.001). Time-varying analysis demonstrated that this association was strongest early in follow-up (HR ≈ 2.5 in year 1) and declined steadily, reaching non-significance (HR ≈ 1.0) by year 4. At year 6, the cumulative incidence of nvAMD was 17.7% in the exposed cohort versus 15.2% in the nonexposed cohort. Baseline AMD stage moderated the effect of CS, with weaker effects of CS for intermediate AMD (Interaction HR = 0.82, 95% CI, 0.78-0.92). Conclusions CS was associated with a modestly increased overall rate of conversion from dAMD to nvAMD; however, the time-dependent pattern suggests that the observed association likely reflects increased surveillance or unrecognized pre-existing nvAMD rather than a sustained biological effect of surgery. The absolute risk difference was small (~3.3% over six years). These findings support careful perioperative evaluation in dAMD patients but do not implicate CS as a long-term driver of neovascular conversion.