Neovascularization in Fellow Eye of Unilateral Neovascular Age-related Macular Degeneration According to Different Drusen Types

Purpose: To investigate the incidence of fellow eye (FE) neovascular age-related macular degeneration (nAMD) in patients with unilateral nAMD according to FE drusen type. Design: Retrospective cohort study. Methods: Between January 2013 and June 2016, 434 consecutive patients with naïve nAMD were enrolled. We selected 280 eligible patients with treatment-naïve, unilateral nAMD for analysis (280/280 = 100% patients were followed up at 2 years; 50/280 = 17.9% patients were followed up at 5 years). The incidence and hazard ratios (HR) of FE nAMD according to age, sex, choroidal thickness, nAMD subtype, and drusen type were analyzed. Results: The 5-year incidence of FE nAMD was 20.9%. The incidences of the soft plus subretinal drusenoid deposits (SDD), soft drusen only, and SDD only groups were 76.4%, 46.2%, and 25.7%, respectively; they were significantly higher than the no drusen group (vs 3.6%; P <.001, P <.001, P <.001). There was no significant difference between the pachydrusen and no drusen groups (7.1% vs 3.6%; P =.101). The multivariate Cox regression hazard model revealed older age (HR, 1.053; P =.031) and drusen type were significant (P =.001). Compared with the no drusen group, the soft drusen plus SDD, soft drusen only, and SDD groups showed an HR of 18.460 (P =.001), 8.302 (P =.015), and 5.465 (P =.082), respectively. Pachydrusen was not shown to be a significant risk factor compared to the no drusen group (HR, 2.417; P =.281). Conclusion: The incidence of FE nAMD was significantly different with respect to drusen type. Soft drusen plus SDD had the highest risk of neovascular AMD, followed by soft drusen only and SDD only.