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 cataract. Anterior chamber instability and/or posterior capsule protrusion remain important risk factors for complications as posterior capsular rupture and postoperative cystoid macular edema. An innovative phacoemulsification handpiece is available with a built-in fluidics pressure sensor that detects pressure in real time to stabilize the anterior chamber during MICS. This study aims to compare anterior chamber flare (ACF), central corneal thickness (CCT) as indicators of surgical trauma between the Centurion vision system with active sentry (Centurion-AS; Alcon, Freiburg, CH) and the Eva phacoemulsification system  (DORC BV, Zuidland, NL).

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 is a prospective, randomized, controlled, observational study involving 134 patients with advanced or mature cataract scheduled for MICS. All patients are operated by three experienced phacoemulsification surgeons using identical techniques, and are randomly included in one of two study arms using the DORC Eva phacoemulsifier or the Centurion-AS at comparable fluidics settings. All patients receive the same postoperative treatment. Primary endpoint is defined as the difference of pre- versus postoperative ACF on day 1 and 7 between Centurion-AS and routine MICS. The secondary endpoints include CCT, central macular thickness (OCT derived) and 5mm corneal volume (Pentacam derived). Patient recruitment for this study is still ongoing. 

By now 67 patients have been enrolled in this study, representing 50 % of the determined overall power. In group 1 surgery was performed via Centurion-AS (n = 36), in group 2 via DORC Eva phacoemulsifier (n = 28). 3  patients were lost in follow-up examination. Both groups show comparable demographic parameters. On day 1 after surgery ACF changes were significantly less in group 1 (6.18 ± 7.9 vs. 11.42 ± 12.6 ph/ms; p = 0.048), as well as 5mm corneal volume (0.77 ± 0.8 vs. 1.36 ± 1.1 mm³; p = 0.015) and CCT (12.3 ± 21.7 vs. 28.2 ± 26.7 µm; p = 0.01). Central macular thickness was not significantly different for both groups. On day 7 after surgery all primary and secondary endpoints showed no statistical significance within the two groups.

We confirmed that intraoperative fluidics and pressure sensing stabilizes the anterior chamber and is associated with decreased postoperative ACF or measures of surgical trauma, thus increasing perioperative safety and feasibility of MICS in advanced or mature cataracts. 1 week after surgery no significant differences between Centurion-AS and routine MICS were observed regarding anterior and posterior ocular segments. Development of postoperative cystoid macular edema was not statistically higher in either one of the two groups, but may not be registered due to the limited observation period of 7 days. More data are needed to confirm these observations.