A Simplified Classification for Age-Related Macular Degeneration Based on Optical Coherence Tomography

Background and objective: As optical coherence tomography (OCT) has enabled the identification of an expanding set of age-related macular degeneration (AMD) risk biomarkers and become central to routine clinical practice, there remains a need for a simplified grading scheme that allows physicians to communicate and synchronize AMD grading directly from standard OCT imaging rather than relying on traditional color fundus imaging. This study aims to establish a standardized OCT-based AMD classification that balances diagnostic accuracy with practicality for use across clinical and research settings.

Patients and methods: Spectral-domain OCT scans were independently graded by two retinal specialists following the newly proposed Stanford OCT-Based AMD Classification (SOAC). Discrepancies were adjudicated by a third independent retinal specialist. Inter-grader agreement was assessed using weighted kappa coefficients.

Results: Among the 109 eyes from 108 patients (mean age 79.61 ± 7.57 years; 41.7% men, 58.3% women), AMD staging based on SOAC was distributed as follows: normal aging in nine patients (8.3%), early AMD in 16 (14.7%), intermediate AMD in 32 (29.4%), neovascular AMD (nAMD) in 18 (16.5%), geographic atrophy (GA) in 20 (18.3%), and combined nAMD and GA in 14 (12.8%). The overall intergrader agreement demonstrated robust consistency, with a weighted kappa value of 0.95 (95% CI: 0.92-0.98), signifying excellent intergrader reliability and reinforcing the validity of SOAC.

Conclusion: SOAC provides a standardized, OCT-based framework for AMD grading that demonstrates high intergrader agreement. By enabling consistent classification from commonly acquired OCT scans, SOAC supports reliable disease staging and facilitates integration across clinical studies and translational research. As imaging and molecular data continue to expand, SOAC can serve as a common OCT-based reference for phenotype refinement and longitudinal AMD studies.