Corneal endothelial cell loss during phacoemulsification: bevel-up versus bevel-down phaco tip.

PURPOSE To compare corneal endothelial cell loss during cataract extraction by phacoemulsification with 2 different phaco-tip positions. SETTING Ophthalmic Research Center and Department of Ophthalmology, Labbafinejad Medical Center, Shahid Beheshti Medical University, Tehran, Iran. DESIGN Randomized clinical trial. METHODS Eyes scheduled for cataract extraction were randomly assigned stop-and-chop phacoemulsification with the phaco tip in the conventional bevel-up position or with the phaco tip in the bevel-down position. During surgery, the effective phacoemulsification time (EPT) was recorded. Preoperative endothelial cell parameters were compared with measurements taken 3 months postoperatively. RESULTS Each group comprised 30 eyes (30 patients). There were no statistically significant differences in age, sex, anterior chamber depth, axial length, or EPT between the 2 groups. The mean preoperative endothelial cell density (ECD) was 2544 cells/mm(2) ± 64 (SD) in the bevel-up group and 2471 ± 59 cells/mm(2) in the bevel-down group (P=.610). Postoperatively, both groups had a significant decrease in ECD. The mean endothelial cell loss was 5.9% in the bevel-up group and 13.6% in the bevel-down group (P=.012). The percentage of hexagonal cells and coefficient of variation in cell size were not different between the 2 groups preoperatively or postoperatively; however, after surgery, there was a significant decrease in the percentage of hexagonal cells in both groups. CONCLUSION Corneal endothelial cell loss during phacoemulsification was significantly higher when the phaco tip was in the bevel-down position than in the conventional bevel-up position. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.