Evaluation of the Occlusion Break Surge Volume in Five Different Phacoemulsification Systems.

Abstract

Purpose: To compare surge volume after occlusion breaks in five phacoemulsification systems.

Methods: A mechanical spring-eye model was used to evaluate the Legion™ Vision System with the Single Use Fluidics Management System (FMS) (LEG), Infiniti™ Vision System with Intrepid™ Plus FMS (INF), Whitestar Signature Pro^® with the OPO73 pack (WSP), Compact Intuitiv^® with the OPO80 pack (CIS), and Stellaris PC^® with the StableChamber cassette (SPC). Transient occlusion break surge volume responses were assessed across a full range of system settings (IOP: 30 to 80 mmHg; vacuum limit: 300 to 650 mmHg; aspiration rate: 20 or 40 cc/min. Oscilloscope waveforms covered stable flow before occlusion, full occlusion, occlusion break, and full recovery to stable flow. Raw oscilloscope data were converted to volumetric and pressure measurements. Fitted average surge traces were generated for each test condition and used to develop an interpolation algorithm to predict transient occlusion break surge events.

Results: The minimum surge volume for all systems occurred at the highest IOP (80 mmHg) and the lowest tested vacuum limit (300 mmHg). Overall, the surge volume increased with increasing vacuum limit and decreasing IOP on the LEG, INF CIS, WSP, and SPC systems. The occlusion break surge volumes (µL [standard deviation]) at 60 mmHg IOP and vacuum limit of 500 mmHg were 70.4 [8.1] for LEG; 87.4 [9.7] for INF; 85.8 [7.2] for CIS; 69.5 [5.0] for WSP; and 151.7 [20.2]) for SPC. A Games-Howell post-hoc test showed significant differences between three groups: A) LEG/WSP, B) CIS/INF, and C) SPC.

Conclusion: The Legion system demonstrated comparable or lower predicted surge volume after occlusion breaks compared to the other phacoemulsification systems evaluated. Reductions in occlusion break surge volumes are expected to decrease the rate of complications and lead to improved outcomes in the clinical cataract surgery setting.