Improving Safety Of Phacoemulsification Cataract Surgery In High-Risk Patients Using Real-Time Anterior Chamber Pressure Sensing And Regulation

Microincision phacoemulsification surgery (MICS) is the standard of care for the treatment of the cataractous lens. Anterior chamber instability and/or posterior capsule protrusion remain the most important risk factors for complications like posterior capsular rupture and postoperative cystoid macular edema. An innovative phacoemulsification handpiece is available with a built-in fluidics pressure sensor detects pressure in real time to stabilize the anterior chamber during MICS. This study aims to compare anterior chamber flare (ACF) minimal corneal thickness (CCT) as indicators of surgical trauma between the Centurion vision system with active sentry (Centurion-AS) and the Eva phacoemulsification system  (DORC BV).

The Department of Ophthalmology of the Medical University of Innsbruck is an ophthalmological tertiary referral center serving a population of approximately 750.000 in Tyrol, Austria.

This was a prospective, randomized, controlled, observational study involving 134 patients with advanced or mature cataract scheduled for MICS. All patients were operated by three experienced phacoemulsification surgeons using an identical technique, and were randomly included in one of two study arms using the DORC Eva phacoemulsifier or the Centurion-AS at comparable fluidics settings. All patients received the same postoperative treatment. Primary endpoint was defined as the difference between pre- and postoperative ACF on days 1 and 7 comparing Centurion-AS and routine MICS. The secondary endpoints included minimal corneal thickness, central macular thickness, 5mm corneal volume and best spectacle corrected visual acuity.

In group 1 surgery was performed via Centurion-AS (n = 65), in group 2 DORC Eva phacoemulsifier was used for MICS (n = 62). 7 patients were lost in follow-up examination. Both groups showed comparable demographic parameters. Change of ACF on day 1 was significantly less in group 1 (6.2 +- 7.7 vs 9.8 +- 11.12 ph/ms; p = 0.037), as were 5 mm corneal volume (0.92 +- 1.0 versus 1.6 +- 1.1 mm3; p=0.004) and  MCT  (12.0 +- 28.8 versus 29.5 +- 25.9 ym; p < 0.001). CMT was not significantly different between the groups. On day 7 all primary and secondary endpoints showed no statistical significance between the groups.

This study confirmes that intraoperative fluidics and pressure sensing stabilizes the anterior chamber and is associated with relatively decreased postoperative ACF and measures of surgical trauma one day after surgery, increasing perioperative safety and feasibility of MICS in advanced or mature cataracts. This difference was no longer observed after one week.  No difference was observed for intraoperative surgical complications or macular thickness.