Royal College of Ophthalmologists' National Ophthalmology Database study of cataract surgery: report 8, cohort analysis of the relationship between intraoperative complications of cataract surgery and axial length.

Objectives: To describe the relationships between axial length and intraoperative complications in patients undergoing cataract surgery.

Design: Cohort analysis of the Royal College of Ophthalmologists' National Ophthalmology Database (RCOphth NOD).

Setting: 110 National Health Service Trusts in England, Health Boards in Wales, Independent Sector Treatment Centres and Guernsey.

Participants: 820 354 patients, aged 18 years or older, undergoing cataract surgery. Eligible operations were those from centres with at least 50 operations with a recorded axial length measurement and age at surgery between 1 April 2010 and 31 August 2019.

Interventions: Phacoemulsification where the primary intention was cataract surgery alone.

Outcome Measures: Posterior capsule rupture (PCR) and other recorded intraoperative complications.

Results: 1 211 520 eligible operations were performed by 3210 surgeons. The baseline axial length was <21 mm (short eyes) for 17 170 (1.4%) eyes, 21-28 mm (medium eyes) for 1 182 513 (97.6%) eyes and >28 mm (long eyes) for 11 837 (1.0%) eyes. The median age at surgery was younger for patients with long eyes than those with short or medium eyes. The rate of any intraoperative complication was higher for short eyes than medium or long with complication rates of 4.5%, 2.9% and 3.3%, respectively (p<0.001). PCR occurred in 1.40% surgeries overall, and in 1.53%, 1.40% and 1.61% of short, medium and long eyes, respectively (p=0.043, not significant at the 1% level).

Conclusions: Overall PCR rates for cataract surgery in RCOphth NOD contributing centres are lower than previously reported and there is little change in PCR rates by axial length. Short eyes were more likely to have an intraoperative complication than medium or long eyes.