1120-6721/984-06$25.00/0 © Wichtig Editore, 2009 European Journal of Ophthalmology / Vol.19 no. 6, 2009 / pp. 984-989 INTRODUCTION The introduction of phacoemulsification has revolutionized cataract surgery. However, the use of ultrasound energy is invariably associated with heat generation, which may cause unwanted damage to the ocular tissue wound and endothelium. Thermal damage to the wound compromises tissue apposition and leads to leakage, which will increase the risk of endophthalmitis. The collagen shrinkage asso- ciated with wound burn also increases surgically induced astigmatism. Use of high ultrasound power and creation of excessive frictional forces generated by contact of the vibrating phacoemulsification tip with the irrigation sleeve are the principal factors identified as risk factors for wound burns (1-6). In order to reduce the total amount of ultrasound energy, several power modulations (pulse, burst, hyperpulse mo- des) have been developed (7). Also, the use of sonic pha- coemulsification instead of ultrasound (8), different nucleus disassembling techniques such as quick chop (9, 10), mi- Comparison of conventional and torsional mode (OZil) phacoemulsification: randomized prospective clinical study ERCÜMENT BOZKURT, SUKRU BAYRAKTAR, SERPIL YAZGAN, MEHMET CAKIR, OSMAN CEKIÇ, HAVVA ERDOGAN, OMER F. YILMAZ Beyoglu Eye Training and Education Hospital, Beyoglu - Turkey PURPOSE. To compare the amount of intraoperative energy used during conventional and torsional phacoemulsification surgery and investigate the changes in corneal endothelial cell density. METHODS. 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. RESULTS. 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). CONCLUSIONS. No statistically significant difference was found between conventional and torsional pha- coemulsification 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 (Eur J Ophthalmol 2009: 19: 984-9) KEY WORDS. Phacoemulsification, Torsional mode (OZil) Accepted: April 2, 2009