Japanese Strabismus Outcomes Assessment and Research Group Study

This retrospective multicenter cohort study collects clinical data from participating academic and high-volume centers in Japan. To minimize chronological bias and maintain feasibility, the observation period depends on the target disease. For common types of strabismus, data extraction is limited to a recent timeframe (e.g., the past 3 years) to avoid the influence of behavioral changes during the coronavirus disease 2019 (COVID-19) pandemic. For rare and complex strabismus, the extraction period extends up to 10 years (from January 2016 to the date of Institutional Review Board approval) to secure an adequate sample size. Statistical analyses will incorporate mixed-effects models to adjust for institutional clustering and differences in patient backgrounds. Missing data will be addressed via multiple imputation before developing prediction models with machine learning algorithms such as random forests.

Inclusion criteria

• Patients diagnosed with strabismus who underwent clinical evaluation or management (including observation for natural history, conservative treatment, or surgery) at participating institutions.
• Observation period for common strabismus: A restricted recent timeframe (e.g., the most recent 3 years) to minimize selection bias.
• Observation period for rare and complex strabismus: Up to 10 years (January 1, 2016, to the date of Institutional Review Board approval) to secure an adequate sample size.

Exclusion criteria

• Patients who formally opted out of data utilization for this study.