Objective: We assessed whether the immediate pressure adjustments provided by a phacoemulsification handpiece with a built-in pressure sensor (Active Sentry, AS) could decrease the amount of energy delivered in the eye during cataract surgery.Methods and analysis: The Study of Active Sentry in Cataract Surgery was a multicentre prospective clinical trial. The Centurion system (Alcon Labs) was used and we compared phacoemulsifications performed with the AS handpiece with procedures using a sensor placed in the phacoemulsifier (non-AS). The primary outcome measure was the cumulative dissipated energy (CDE) used during the procedures. The secondary outcome measures were the total, longitudinal and torsional ultrasound (US) times, the duration of the surgery and the amount of fluid used during the surgeries.Results: The study analysed 1432 (800 AS and 632 non-AS) procedures. The mean patient age was 72.4 +/- 10.0 years. The median CDE was respectively 6.3 (IQR 3.5-9.9) and 6.7 (IQR 4.5-11.5) with and without AS (p=0.0001). The median US time was, respectively, 48.0 s (IQR 34.0-68.0) and 55.0 s (IQR 38.0-80.0) with and without AS (p<0.0001). Torsional and longitudinal US times were reduced with AS. The median duration of the procedure was, respectively, 9.0 min (IQR 7.0-12.0) and 10.0 min (IQR 7.0-13.0) (p=0.0002) with and without AS. The median balanced salt solution volume used was 52.0 cm(3) (IQR 41.0-72.0) and 57.0 cm(3) (IQR 42.0-81.0) with and without AS (p=0.0018).Conclusion: The phacoemulsifications performed with a pressure sensor built in the handpiece delivered less energy in the eye and were shorter.
