Variations in nAMD and PCV Phenotypes and Treatment Outcomes Across Singaporean, Canadian Asian, and Canadian Caucasian Populations.

PURPOSE: To compare the frequency of polypoidal choroidal vasculopathy (PCV) features, treatment patterns, and one-year outcomes across Singaporean Asian, Canadian Asian, and Canadian Caucasian populations with neovascular age-related macular degeneration (nAMD) using optical coherence tomography (OCT)-based diagnostic criteria. DESIGN: Retrospective, multicenter, comparative study. PARTICIPANTS: A total of 327 treatment-naïve patients with nAMD: 181 from Singapore National Eye Centre and 146 from Vancouver, Canada (89 Caucasian, 57 Asian). METHODS: PCV was diagnosed using modified Asia-Pacific Ocular Imaging Society non-indocyanine green angiography OCT-based criteria (sharp-peaked pigment epithelial detachment and sub-retinal pigment epithelium ring-like lesion). Baseline OCT features, treatment patterns, and 12-month outcomes were compared across the three ethnic groups. MAIN OUTCOME MEASURES: PCV prevalence, OCT-based morphological features, treatment patterns, and change in best-corrected visual acuity (BCVA) at 12 months. RESULTS: PCV prevalence was similar between Singaporean Asian (42.5%) and Canadian Asian (42.1%) groups, both significantly higher than Canadian Caucasians (13.5%, P<0.01). OCT features in PCV eyes were consistent across ethnic groups, including macular predominance (79.2-83.3%), double-layer sign (83.3-93.5%), low soft drusen prevalence (4.2-8.3%), and subfoveal choroidal thickness >200 µm. Treatment patterns differed: bevacizumab predominated in Canada (65.0-70.0% for PCV), while Singapore used varied agents with photodynamic therapy in 31.1%. At 12 months, BCVA improved in Singaporean PCV eyes (-0.22 logMAR, P<0.01). In typical nAMD, BCVA improved significantly across all three groups. CONCLUSIONS: Ethnic differences in PCV prevalence persist regardless of geographic location, supporting a predominant genetic basis for PCV susceptibility. OCT-based PCV features are consistent across ethnicities, while treatment patterns vary substantially between healthcare systems. Non-invasive OCT-based diagnostic criteria enable reliable cross-ethnic PCV comparison when indocyanine green angiography is unavailable.