Post-Occlusion Surge Performance Of Leading Phaco Machines: A Comparison

Purpose

To compare the response to post-occlusion surge and fluidic efficiency of leading phacoemulsification machines including Alcon Centurion, Bausch & Lomb PC Stellaris, BVI new phaco-vitrectomy platform, DORC Eva Nexus.

Zacharias fixture simulating phaco tip occlusion cycles and measuring volume pressure changes within a collapsible model anterior chamber with calibrated impedance similar to the human eye was used. 

Each phaco handpiece mounting a straight 21G tip was mounted on the fixture equipped with pressure and volume sensor intended to describe the entire occlusion-disocclusion cycle and specifically the post-occlusion aspiration peak. All phaco handpieces were connected to their respective consoles and standard flow, aspiration vacuum and irrigation fluid pressure were compared. The Fixture, model anterior chamber was calibrated before each set of measures, to ensure repeatability. 

Volume loss after occlusion break varied between 15-180 microliters as aspiration pressure rose from 200-600 mmHg at 35 mmHg infusion pressure and between 15-160 microliters when infusion pressure was set at 55 mmHg. Different phaco machines showed significant differences in volume replacement capability: at challenging aspiration settings (600 mmHg) Alcon Centurion and BVI new platform behaved similarly, and significantly better than other consoles (p<0.05). Time needed to regain 90% of preset pressure after occlusion break also varied significantly among different manufacturers, between 0.30-4 seconds, and some consoles took more than 5 seconds to regain preset pressure (p<0.05). 

Active fluidics phacoemulsification consoles proved more efficient in minimizing the dangerous loss of volume and pressure after occlusion break, losing significantly less volume in a model collapsable anterior chamber, restoring more promptly the desired pressure.  Phaco consoles with active fluidics control regained preset pressure more promptly and significantly sooner that all other machines (<1 s regardless of aspiration pressure 200-600 mmHg both at 30 and 55 mmHg infusion pressure).