Experimental study comparing 2 different phacoemulsification systems with intraocular pressure control during steady-state flow and occlusion break surge events.

PURPOSE: To compare peak surge and surge duration time after occlusion break, incision leakage compensation, and passive vacuum for 2 phacoemulsification systems. SETTING: Carl Zeiss Meditec AG, Oberkochen, Germany. DESIGN: Laboratory study. METHODS: A spring-eye model was used to test Alcon Centurion Vision and Zeiss Quatera 700 systems. Peak surge and duration was measured after an occlusion break. Quatera tested in flow and vacuum priority modes. Vacuum limits ranged from 300 to 700 mm Hg with intraocular pressure (IOP) set at 30 mm Hg, 55 mm Hg, and 80 mm Hg. IOP vs incision leakage rates of 0 to 15 cc/min and passive vacuum were measured. RESULTS: At 30 mm Hg IOP set point and vacuum limits ranging 300 to 700 mm Hg, the surge duration time after occlusion break ranged 419 to 1740 milliseconds (ms) for Centurion, 284 to 408 ms for Quatera in the flow mode, and 282 to 354 ms for Quatera in the vacuum mode. At 55 mm Hg, values ranged 268 to 1590 ms for Centurion, 258 to 471 ms for Quatera in the flow mode, and 239 to 284 ms for Quatera in the vacuum mode. At 80 mm Hg, values were 243 to 1520 ms for Centurion, 238 to 314 ms for Quatera in the flow mode, and 221 to 279 ms in the vacuum mode. Centurion exhibited slightly less peak surge than the Quatera. At 55 mm Hg: incision leakage rates 0 to 15 cc/min, Quatera held the IOP within ±2 mm Hg of target; Centurion was unable to hold IOP target allowing a 11.7 mm Hg decrease with 32% higher passive vacuum. CONCLUSIONS: Quatera demonstrated slightly higher surge peak values and notably shorter surge duration times after occlusion break than Centurion. Quatera demonstrated better incision leakage compensation and lower passive vacuum than Centurion.

Phacoemulsifier occlusion break surge volume reduction.

PURPOSE: To compare the volumetric occlusion break surge responses of phacoemulsification units from 1 company over 3 generations under varying vacuum limits and target intraocular pressure (IOP) settings. SETTING: Alcon Research, Ltd., Lake Forest, California, USA. DESIGN: Experimental study. METHODS: Three generations of phacoemulsification units (Infiniti Vision System, Centurion Vision System, and Centurion Vision System with Active Sentry upgrades) were tested. Volumetric surge responses were measured after occlusion breaks at vacuum limits of 200 mm Hg, 300 mm Hg, 400 mm Hg, 500 mm Hg, and 600 mm Hg and target IOPs of 30 mm Hg, 55 mm Hg, and 80 mm Hg. An acrylic test chamber with a piston attached to 3 springs modeled the human eye in this study. The springs were calibrated to mimic volumetric changes in the eye over a wide range of IOPs. RESULTS: Occlusion break surge volumes varied from 17.4 µL to 153 µL, corresponding to 7% and 61%, respectively, of the aqueous volume in the average phakic eye and to 4% and 33% of the aqueous volume in the average aphakic eye. CONCLUSION: Occlusion break surge volumes decreased with increasing target IOP, decreasing vacuum limit, and each generational increment in the phacoemulsification system.

Aqueous volume loss associated with occlusion break surge in phacoemulsifiers from 4 different manufacturers.

PURPOSE: To evaluate aqueous volume losses associated with occlusion breaks at varying vacuum limits in phacoemulsification systems from 4 different manufacturers. SETTING: Alcon Research Ltd., Lake Forest, California, USA. DESIGN: Experimental study. METHODS: The anterior chamber was modeled using the spring eye model. Systems tested included the Centurion, Whitestar Signature, Stellaris PC, and EVA. Occlusion breaks were actuated at vacuum limits of 200, 300, 400, 500, and 600 mm Hg and a target intraocular pressure of 55 mm Hg. RESULTS: The model eye piston reached its measurement limit just below 600 mm Hg on the EVA and just above 400 mm Hg on the Stellaris PC. Higher vacuum limits could not be tested on these 2 units. Surge volumes varied from 17 to 77 µL on the Centurion, 30 to 103 µL on the Whitestar Signature, 67 µL to 163 µL on the Stellaris PC, and 47 to 165 µL on the EVA. Assuming an average phakic eye aqueous volume of 250 µL, these µL values correspond to percent aqueous volume losses of 7% to 31% on the Centurion, 12% to 41% on the Whitestar Signature, 27% to 65% on the Stellaris PC, and 19% to 66% on the EVA. Surge responses increased on all machines with each increment in vacuum limit. The Centurion had the lowest surge volumes across all vacuum limits. CONCLUSIONS: Occlusion break surge volumes vary considerably across phacoemulsification platforms. Severe chamber shallowing might occur if an occlusion break occurs under high vacuum on some systems.

Comparison of occlusion break responses and vacuum rise times of phacoemulsification systems.

BACKGROUND: Occlusion break surge during phacoemulsification cataract surgery can lead to potential surgical complications. The purpose of this study was to quantify occlusion break surge and vacuum rise time of current phacoemulsification systems used in cataract surgery. METHODS: Occlusion break surge at vacuum pressures between 200 and 600 mmHg was assessed with the Infiniti® Vision System, the WhiteStar Signature® Phacoemulsification System, and the Centurion® Vision System using gravity-fed fluidics. Centurion Active FluidicsTM were also tested at multiple intraoperative pressure target settings. Vacuum rise time was evaluated for Infiniti, WhiteStar Signature, Centurion, and Stellaris® Vision Enhancement systems. Rise time to vacuum limits of 400 and 600 mmHg was assessed at flow rates of 30 and 60 cc/minute. Occlusion break surge was analyzed by 2-way analysis of variance. RESULTS: The Centurion system exhibited substantially less occlusion break surge than the other systems tested. Surge area with Centurion Active Fluidics was similar to gravity fluidics at an equivalent bottle height. At all Centurion Active Fluidics intraoperative pressure target settings tested, surge was smaller than with Infiniti and WhiteStar Signature. Infiniti had the fastest vacuum rise time and Stellaris had the slowest. No system tested reached the 600-mmHg vacuum limit. CONCLUSIONS: In this laboratory study, Centurion had the least occlusion break surge and similar vacuum rise times compared with the other systems tested. Reducing occlusion break surge may increase safety of phacoemulsification cataract surgery.