Real-Time Dynamic Changes in Intraocular Pressure following Occlusion Break: Comparing Two Phacoemulsification Systems

PURPOSE Compare realtime intraocular pressure(IOP) response to occlusion break event in two phacoemulsification systems. SETTING Iladevi Cataract & IOL Research Centre,India. DESIGN Randomized,experimental study. METHODS 10 rabbits(20 eyes) randomized to one of two groups: group I(n=10 eyes), Centurion Vision system with active fluidics, or, group II(n=10 eyes), Centurion with Active Sentry upgrade. Within each group, parameter set 1(IOP 30mmHg, aspiration flow rate(AFR) 20cc/min, vacuum 600mmHg) and parameter set 2(IOP 50mmHg, AFR 25cc/min, vacuum 600mmHg) were tested. Realtime rate of drop and rise of IOP following occlusion break event(mmHg/second) and percentage(%) reduction of IOP from maximum during nuclear fragment removal were compared.Results:Rate of drop of IOP following 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=0.006; and 256 + 45.05 vs 165.25 + 51.80 in parameter set 2,p=0.005), suggesting faster recovery to baseline IOP following occlusion break. Mean % reduction of IOP from maximum was significantly higher in group I(P=0.003). CONCLUSION Rise of IOP to baseline following occlusion break event was faster and mean % reduction of IOP from maximum during nuclear fragment removal was lower when using the Centurion Vision system with the Active Sentry upgrade compared to 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.