Comparison of conventional and torsional mode (OZil) phacoemulsification: randomized prospective clinical study

Abstract

To compare the amount of intraoperative energy used during conventional and torsional phacoemulsification surgery and investigate the changes in corneal endothelial cell density. In this study, a total of 100 eyes in patients with age-related cataract (mean age 68.9 years) were included. Patients were randomly allocated into conventional (group 1) or torsional (OZil, group 2) phacoemulsification. Mean nuclear grade made according to Lens Opacities Classification System II was not different in the 2 groups. Total ultrasound time (USTT), cumulative dissipated energy (CDE), and the percent of total equivalent power in position 3 (%USTEPiP3) were compared between the 2 groups. There were 47 eyes in group 1 and 53 eyes in group 2. Patient age and sex were matched between the 2 groups (p=0.49, p=0.08). Mean USTT was 1.6+/-1.1 minutes (m) in group 1 and 1.5 +/- 0.9 m in group 2 (p=0.55). Average CDE was 29.9+/-16.9 in group 1 and 25.2+/-19.1 in group 2 (p=0.20).Mean %USTEPiP3 was 27.0%+/-8.5% in group 1; however, it was 22.4%+/-6.6% in group 2 (p=0.003). At the first postoperative day, mean corneal edema was graded as 0.25+/-0.5 in group 1 and 0.18 +/- 0.4 in group 2 (p=0.47). At the first postoperative week, it was found to be 0.02+/-0.15 in group 1 and 0.03+/-0.27 in group 2 (p=0.71). ECD loss was 6.7%+/-3.3% in group 1 and 4.2%+/-5.7% in group 2 (p=0.56). No statistically significant difference was found between conventional and torsional phacoemulsification with respect to USTT and CDE. Torsional mode led to a significant reduction in US power in footswitch position 3. Torsional mode also appears to be associated with less loss of ECD.