Effect of phaco‐tip orientation during phacoemulsification surgery ( TIPS ) on endothelial cell loss: Results of a randomized clinical trial

PURPOSE: To compare corneal endothelial cell (CEC) loss, central corneal thickness (CCT) and intraoperative complications 1 month post-phacoemulsification using bevel-up versus bevel-down tip orientation with the direct-chop technique. METHODS: Design: Multicentre, triple-masked, randomized controlled parallel group trial. PARTICIPANTS: Adults (≥18 years) with cataracts. METHODS: Participants were randomized 1:1 to undergo phacoemulsification with either a bevel-up (n = 241) or bevel-down (n = 239) using a standardized direct chop technique; Main outcome measures: Mean difference in CEC at 1 month, adjusted for baseline CEC using analysis of covariance with the intention-to-treat principle. Secondary outcomes included change in CCT and intraoperative complications. Subgroup analyses were conducted by cataract grade and baseline endothelial cell density (ECD). RESULTS: ; 95% CI: -54.37 to 64.46; p = 0.868; mean CEC loss %: 9.19 (95% CI: 7.7-10.7) (bevel-up) and 9.07 (95% CI: 7.2-10.9) (bevel-down); p = 0.919). Exploratory subgroup analyses by baseline endothelial cell count and cataract hardness showed no statistically significant differences in CEC loss between bevel orientations. Changes in CCT were comparable and complications infrequent across treatment arms (bevel-up (5.8%); bevel-down (5.0%)). CONCLUSION: In routine direct-chop phacoemulsification with adequate preoperative endothelial counts, bevel orientation (bevel-up vs. bevel-down) results in a negligible difference in one-month endothelial cell loss and infrequent intraoperative complication rates. Bevel orientation is not a major determinant of endothelial cell loss in uncomplicated cases, allowing surgeons to select either orientation based on personal preference.