PURPOSE: To evaluate efficacy and safety of phacoemulsification using Torsional modality with different parameters setting for hard nucleus cataract extraction.
DESIGN: A prospective, randomized clinical study.
METHODS: A clinical practice study conducted at the Cataract Service, Zhongshan Ophthalmic Center, Sun-Yat-Sen University, and Guangzhou. One eye each from 198 consecutive patients with cataract density grade IV according to Emery-Little system classification system, requiring phacoemulsification and intraocular lens (IOL) implantation were included. Eyes were randomly assigned to Linear Torsional combined with Ultrasound power group (Linear Tor+ US group, n=66), 100% Fixed Torsional group (Fixed Tor group, n=65) and conventional Ultrasound burst group (US group, n=67). All surgeries were performed by a single experienced surgeon and outcomes evaluated by another surgeon masked to treatment. Intraoperative parameters were Ultrasound Time (UST), Cumulative Dissipated Energy (CDE) and surgical complications. Patients were examined on post-op day 1, 7 and 30. Postoperative outcomes were final best corrected visual acuity (BCVA), average central and incisional corneal thickness and central endothelial cell counts.
RESULTS: Mean UST was lower in Fixed Tor group than in US group and in Lin US +Tor group (P≤0.0001). Mean CDE was lower in Lin Tor + US group and in Fixed Tor group than in US group (P≤0.0001). Comparing with the two Tor group, the US group had lower average BCVA on post-op 1, 7 (P≤0.0001) and 30 (P>0.01), greater average central corneal and incisional thickness on day 1, 7 (P≤0.0001) and 30 (P>0.01) and higher average corneal endothelial cell losses on day 7 and 30 days (P≤0.0001).
CONCLUSIONS: Torsional combined with Ultrasound power or high fixed Torsional amplitude can provide more effective hard nucleus phacoemulsification than conventional Ultrasound modality.