Comparison of system metrics using minimal threshold ultrasound settings in microcoaxial phacoemulsification
Objective: To determine if minimal threshold torsional ultrasound settings result in improved systemic metrics compared with standard linear torsional ultrasound in microcoaxial phacoemulsification. Materials and methods: Cataracts of similar density, 2+ or greater nuclear sclerosis, in both eyes of 18 patients (N = 36 eyes) needing bilateral cataract surgery were extracted using the OZil torsional handpiece. One eye had surgery performed with standard 100% linear torsional ultrasound (range, 0-100%), and the contralateral eye had surgery performed using threshold torsional ultrasound (range, 30-100%). All other settings were similar in each group. Intraoperative measurements reviewed included cumulative dissipated energy (CDE), infusion fluid use, torsional time, aspiration time, and average torsional amplitude. Results: On average, the CDE, infusion fluid use, aspiration time, and torsional time were significantly lower in the threshold torsional ultrasound setting group compared with the standard linear torsional ultrasound group. Conclusions: Threshold torsional ultrasound settings result in better systemic metrics in patients with 2+ or greater nuclear sclerotic cataracts. Lower CDE, torsional time, and balanced salt solution use may translate into improved clinical outcomes. Further studies are necessary to validate and expand upon these findings. © 2010 by Lippincott Williams & Wilkins.