Occlusion Break Surge Performance of a Next Generation Phacoemulsification System

PURPOSE: To compare occlusion break surge volumes of UNITY® Vitreoretinal Cataract System (UVCS) with CENTURION® Vision System with Active Sentry™ (CAS). SETTING: Alcon Research, Ltd., Lake Forest, California, USA. DESIGN: Experimental study. METHODS: An eye model representing average human eye compliance was used to determine average occlusion break surge volumes. UVCS was tested at target intraocular pressures (IOPs) of 20, 30, 40, 50, 60, and 80 mmHg; vacuum limits of 300, 400, 500, 600, and 650 mmHg; and aspiration flow rates of 20 and 40 cc/min. CAS was tested at target IOPs of 30, 40, 50, 60, and 80 mmHg, and at the same set vacuum limits and aspiration flow rates as UVCS. Additionally, a second order polynomial was fit to the entire data set to compare UVCS and CAS at a target IOP of 20 mmHg. RESULTS: After calculating sample means at each setpoint combination, the largest mean surge volume was 48 µL for UVCS and 75 µL for CAS, corresponding to 19% and 30%, respectively, of the average human phakic anterior chamber volume. For all common setpoint combinations, mean occlusion break surge volumes were 44% lower for UVCS than CAS. At a flow rate of 40 cc/min and IOP setpoint of 20 mmHg, UVCS showed a 46% average decrease across all vacuum limits. CONCLUSION: UVCS demonstrated lower mean surge volumes following occlusion break than CAS. This may give surgeons greater confidence operating at lower IOPs and may reduce the risk of posterior capsule rupture, especially in complex cases.