Four learning phases in cataract surgery revealed by complication rates among novice surgeons at a Japanese teaching center

Cataract surgery education requires balancing surgical training with patient safety, yet the precise phases of surgical skill development remain unclear. Here we analyze 4255 cataract surgeries performed by 15 novice surgeons to identify distinct phases in the learning curve based on complication rates. Using a custom smoothing filter and the PELT (Pruned Exact Linear Time) algorithm, we identified four distinct phases: Phase 1 (cases 1–87) with a complication rate of 3.18% (95% CI 3.13–3.24%), Phase 2 (cases 88–189) with 1.68% (95% CI 1.52–1.85%), Phase 3 (cases 190–534) with 0.79% (95% CI 0.77–0.81%), and Phase 4 (cases 535–711) with 0.18% (95% CI 0.16–0.20%). The experience speed stabilized after approximately 123 cases, and novice surgeons required 535 cases to achieve complication rates comparable to experienced surgeons (0.53%). Notably, surgeons with less than 535 cases accounted for 40.9% of all complications in our educational setting. The overall complication rate for the first 50 cases was 3.1%, lower than previously reported international rates (4.8–11.6%). These findings provide statistical evidence for the stages of surgical proficiency development and suggest that structured training programs should be tailored to these distinct learning phases to optimize surgical outcomes and patient safety.