The effect of increasing power when grooving using phacoemulsification

Rhett S Thomson,1,2 Brian A Bird,3 Lance A Stutz,4 Joshua B Heczko,1 Ashlie A Bernhisel,1 William R Barlow,1 Brian Zaugg,1 Randall J Olson,1 Jeff H Pettey1 1Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA; 2University of Utah School of Medicine, Salt Lake City, UT 84132, USA; 3University of Nevada Reno School of Medicine, Reno, NV 89557, USA; 4University of Texas Southwestern Medical School, Dallas, TX 75390, USA Purpose: To determine optimal power settings on the Centurion Vision System during the grooving step in cataract surgery.Methods: Intact porcine lenses hardened by formalin and placed in a chamber designed to simulate the anterior chamber of the eye were used to test longitudinal power at 40%, 70%, and 100% and torsional power at 0%. Flow rate was set at 40 mL/min. Vacuum was set at 400 mmHg, intraocular pressure was set at 50 mmHg, and a balanced phacoemulsification tip with a 20 degree tip and a 30 degree bevel was used. Efficiency (time to groove the lens in half) was determined.Results: Increasing longitudinal power from 40% to 70% increased efficiency by 28% (P<0.05), and by 32% (P<0.05) when increasing longitudinal power from 40% to 100%. There was no statistically significant increase in efficiency from 70% to 100%.Conclusion: For the tested variables, a longitudinal power of 70% was determined to be most efficient during the grooving step of cataract surgery for equivalent 3–4+ nuclei. Further increases in power demonstrated no statistically significant improvement in efficiency. Keywords: settings, longitudinal power, efficiency, porcine lens mode