Auckland Cataract Study IV: Practical application of NZCRS cataract risk stratification to reduce phacoemulsification complications.

IMPORTANCE: Reduction of intraoperative complications in phacoemulsification cataract surgery. BACKGROUND: To assess practicability of a risk stratification system, the New Zealand Cataract Risk Stratification (NZCRS) system, in a major teaching hospital service, without investigator oversight, to ascertain whether benefits identified in research studies are maintained in busy clinical practice. DESIGN: Prospective cohort study in a major public teaching hospital. PARTICIPANTS: Five hundred cases of phacoemulsification cataract surgery. METHODS: NZCRS system inserted into 621 consecutive preoperative cataract patient files. Recommendation to allocate higher-risk cases to experienced surgeons. MAIN OUTCOME MEASURES: NZCRS system uptake and adherence, appropriate identification of high risk cases and intraoperative complication rates. RESULTS: NZCRS scores calculated in 500 of 621 (80.5%) cases and 98 (19.6%) scored as "high risk." Cataract surgery (N = 500) performed by: 12 Registrars (20%), 4 Fellows (7.2%), 26 Consultants (72.8%). Risk scores adhered to in 99%. Overall intraoperative complications (3.0%) included iris prolapse 1.6% and posterior capsule tear 0.8%. No statistical difference in complication rates identified between surgeon grades. Mean best-corrected visual acuity was 6/10 (20/32). Postoperatively, cystoid macular oedema occurred in 3.2%. Rescoring by an experienced investigator noted a greater number of "high risk scores" (31.6% vs 19.6%) related to differences in subjective scoring of anterior chamber depth and cataract density. CONCLUSIONS AND RELEVANCE: Practical uptake of cataract risk stratification was promising in this study with NZCRS calculated in 80.5% with 99% adherence to scoring recommendations. Compared to baseline studies, in the day-to-day clinical setting, a continued, decreasing trend in frequency and severity of intraoperative complications was noted. Subjective variability of risk scoring may be further improved by better, objective, standardization.