Real-time dynamic changes in intraocular pressure after occlusion break: comparing 2 phacoemulsification systems

Purpose: To compare real-time intraocular pressure (IOP) response to occlusion break event in 2 phacoemulsification systems. Setting: Iladevi Cataract and IOL Research Center, India. Design: Randomized, experimental study. Methods: Rabbits were randomized to:Group I (n = 10 eyes), Centurion Vision system with active fluidics, or, Group II (n = 10 eyes), Centurion with Active Sentry. Within each group, parameter set 1 (IOP 30 mm Hg, aspiration flow rate [AFR] 20 mL/min, and vacuum 600 mm Hg) and parameter set 2 (IOP 50 mm Hg, AFR 25 mL/min, and vacuum 600 mm Hg) were tested. Real-time rate of drop and rise of IOP after occlusion break event (mm Hg per second) and percentage reduction of IOP from maximum during nuclear fragment removal were compared. Results: 10 rabbits (20 eyes) were included. Rate of drop of IOP after occlusion break was not significantly different between groups. Rate of rise of IOP was statistically significantly higher in Group II with both parameter sets (199.09 ± 69.28 vs 94.33 ± 45.66 in parameter set 1, P = .006; and 256 ± 45.05 vs 165.25 ± 51.80 in parameter set 2, P = .005), suggesting faster recovery to baseline IOP after occlusion break. The mean percentage reduction of IOP from maximum was significantly higher in Group I (P = .003). Conclusions: Rise of IOP to baseline after occlusion break event was faster and mean percentage reduction of IOP from maximum during nuclear fragment removal was lower when using the Centurion Vision system with the Active Sentry upgrade compared with the traditional handpiece. The ability to sense IOP at the level of the handpiece with the Active Sentry upgrade allows faster mitigation of surge response.