Design and Baseline Characteristics of the Korean Age-Related Maculopathy Study (KARMS): A Nationwide Multicenter Prospective Observational Study

<h2>ABSTRACT</h2><h3>Purpose</h3> To describe the design and baseline characteristics of the Korean Age-Related Maculopathy Study (KARMS), a nationwide prospective cohort investigating age-related macular degeneration (AMD) in Koreans. <h3>Design</h3> A 5-year prospective observational study conducted across 33 tertiary hospitals and ophthalmology clinics in Korea. <h3>Participants</h3> A total of 1,159 Korean participants diagnosed with non-exudative or exudative AMD <h3>Methods</h3> Participants aged 50–80 years were assigned to the ASIANO arm (non-exudative) or KEATS arm (newly diagnosed exudative AMD). ASIANO Arm 1 included bilateral intermediate AMD with classic drusen (soft, reticular pseudodrusen, cuticular, or calcified drusen) without advanced AMD. ASIANO Arm 2 included pachychoroid spectrum disease with unilateral or bilateral findings such as pachydrusen with retinal pigment epithelium (RPE) undulation, focal attenuation of inner choroidal vessel and dilated outer choroidal vessels or pigmentary abnormalities corresponding RPE elevation or disruption in optical coherence tomography (OCT), without significant classic drusen. The KEATS arm comprised active exudative AMD, including typical exudative macular neovascularization, polypoidal choroidal vasculopathy, and retinal angiomatous proliferation. All underwent standardized multimodal imaging at baseline and are followed annually. <h3>Main Outcome Measures</h3> Baseline demographic, behavioral, and ocular characteristics across drusen-driven, pachychoroid-driven, and exudative AMD phenotypes. <h3>Results</h3> Of the 1,409 individuals screened, 1,159 were enrolled (ASIANO 1: 551; ASIANO 2: 317; KEATS: 291). ASIANO Arm 1 participants were older, predominantly female, and universally bilateral; Arm 2 participants were younger, more often male, and frequently unilateral. KEATS showed a high proportion of patients with polypodal choroidal vasculopathy (39.5%, patient-based) and male predominance. Behavioral profiles also differed: the KEATS arm had lower eye-supplement use, higher smoking exposure, and less frequent sunglasses/sun-visor use. Exploratory follow-up analyses suggested differing rates of exudative conversion between ASIANO Arm 1 and Arm 2. <h3>Conclusions</h3> KARMS is the first large-scale, nationally representative prospective cohort in Koreans, distinguishing drusen-driven and pachychoroid-driven maculopathies phenotypes and detailing exudative subtypes. These baseline data provide a foundation for future phenotype-specific progression analyses and management strategies in Asian populations.