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

Abstract

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. Retrospective, multicenter, comparative study. A total of 327 treatment-naïve patients with nAMD: 181 from Singapore National Eye Centre and 146 from Vancouver, Canada (89 Caucasian, 57 Asian). 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. PCV prevalence, OCT-based morphological features, treatment patterns, and change in best-corrected visual acuity (BCVA) at 12 months. 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. 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.