Purpose To validate a porcine lens model by comparing density and ultrasound (US) with known human standards using the Infiniti Ozil with Intelligent Phacoemulsification (torsional), Whitestar Signature Micropulse (longitudinal), and Ellips FX (transversal) modalities. Setting Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Design Experimental study. Methods Lens nuclei were formalin soaked in hour-based intervals and divided into 2.0 mm cubes. Density was characterized by crushing experiments and compared with known human measures. Efficiency and chatter were examined. Results The mean weight to cut thickness in half ranged from 16.9 g ± 5.5 (SD) in the 0-hour group to 121.3 ± 47.5 gm in the 4-hour group. Lenses in the 2-hour group (mean 70.2 ± 19.1 g) best matched human density ( P =.215). The mean efficiency ranged from 0.432 ± 0.178 seconds to 9.111 ± 2.925 seconds; chatter ranged from zero to 1.85 ± 1.927 bounces. No significant difference was detected when comparing the 2-hour formalin group with human lenses in torsional and transversal US. There was no significant difference between transversal and torsional modalities, consistent with human studies. Although longitudinal (6 milliseconds on, 12 milliseconds off) was significantly more efficient at 50% power than at 25%, there was no significant difference compared with transversal or torsional US. Conclusions Animal lenses soaked for 2 hours in formalin were most comparable to human lenses. Longitudinal US may be an acceptable alternative to torsional and transversal US. Financial Disclosure Dr. Olson has been a consultant to Abbott Medical Optics, Inc., Becton, Dickinson and Co., and Allergan, Inc., and received grant support from Abbott Medical Optics, Inc. and Allergan, Inc. No author has a financial or proprietary interest in any material or method mentioned.

Porcine lens nuclei as a model for comparison of 3 ultrasound modalities regarding efficiency and chatter

PURPOSE To compare cumulative dissipated energy between two phacoemulsification machines. SETTING An ambulatory surgical center, Honolulu, Hawaii, USA. DESIGN Retrospective chart review. METHODS A total of 2,077 consecutive cases of cataract extraction by phacoemulsification performed by five surgeons from November 2012 to November 2014 were included in the study; 1,021 consecutive cases were performed using the Infiniti Vision System, followed by 1,056 consecutive cases performed using the Centurion Vision System. RESULTS The Centurion phacoemulsification system required less energy to remove a cataractous lens with an adjusted average energy reduction of 38% (5.09 percent-seconds) (P<0.001) across all surgeons in comparison to the Infiniti phacoemulsification system. The reduction in cumulative dissipated energy was statistically significant for each surgeon, with a range of 29%-45% (2.25-12.54 percent-seconds) (P=0.005-<0.001). Cumulative dissipated energy for both the Infiniti and Centurion systems varied directly with patient age, increasing an average of 2.38 percent-seconds/10 years. CONCLUSION The Centurion phacoemulsification system required less energy to remove a cataractous lens in comparison to the Infiniti phacoemulsification system.

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Comparison of cumulative dissipated energy between the Infiniti and Centurion phacoemulsification systems.

Purpose To evaluate the optimum on time for the most efficient removal of lens fragments using micropulsed ultrasound (US). Setting John A. Moran Eye Center Laboratories, University of Utah, Salt Lake City, Utah, USA. Design Experimental study. Methods Twenty porcine lens nuclei were soaked in formalin for 2 hours and then divided into 2.0 mm cubes. Using an US machine with a 0.9 mm bent and a 30-degree bevel tip, the on time was varied every millisecond (ms) from 2 ms to 10 ms with the off time kept constant at 10 ms. Efficiency (time to lens removal) and chatter (number of lens fragment repulsions from the tip) were determined. Results The most efficient phacoemulsification was achieved with an on time of 6 ms. On times shorter than 6 ms were significantly less efficient (R2 = .82, P=.04). Greater on times did not result in a significant difference in efficiency (R2 = .03, P=.78) but did appear to have more chatter events when comparing 9 to 10 ms with 2 to 8 ms (P Conclusions With micropulsed longitudinal US, a 6 ms on time was equally as efficient as longer on times, while shorter on times (2 to 5 ms) had decreased efficiency. At 9 ms and 10 ms on time, significantly more chatter was noted. Therefore, to maximize phacoemulsification, an on-time setting of 6 ms is recommended. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Optimum on-time duty cycle for micropulse technology

Determining optimal torsional ultrasound power for cataract surgery with automatic longitudinal pulses at maximum vacuum ex vivo.

Purpose To evaluate the optimum off time for the most efficient removal of lens fragments using micropulse ultrasound (US). Setting John A. Moran Eye Center Laboratories, University of Utah, Salt Lake City, Utah, USA. Design Experimental study. Methods Porcine lens nuclei were soaked in formalin for 2 hours and then cut into 2.0 mm cubes using the Signature US machine with a bent 0.9 mm phaco tip with a 30-degree bevel. The on time was 7 milliseconds (ms), and the off time was varied from 2 to 20 ms in 2 ms steps. Phacoemulsification efficiency (time for fragment removal) and chatter (number of times the fragment bounced from the tip) were measured. Results A nonsignificant linear increase in efficiency was observed with 2 to 6 ms of off time ( R 2  = .87, P  = .24). A significant linear decrease in efficiency was observed with 6 to 20 ms ( R 2  = .74, P  = .006). Conclusions With micropulse longitudinal US, 6 to 7 ms of off time was as efficient as shorter off times; longer off times (8 to 20 ms) showed decreased efficiency. Chatter was minimal and statistically similar throughout. To maximize phacoemulsification US efficiency, an off-time setting of 6 ms is recommended. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Determining optimal ultrasound off time with micropulse longitudinal phacoemulsification

Purpose To compare efficiency and chatter of Infiniti Ozil with and without Intelligent Phacoemulsification (IP) and the Signature Ellips with and without FX. Setting John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Design Experimental study. Methods Brunescent 2.0 mm human lens cubes were created by an instrument devised for this study. Cubes were tested (10 per test) for time of particle removal (efficiency) and for the number of times the lens particle bounced off the tip (chatter) at 300 mm Hg and 550 mm Hg, 50% and 100% power, and 50% and 100% amplitudes (amplitude for Ozil only). Results Of the ultrasound settings, efficiency varied from a mean of 3.3 seconds ± 1.4 (SD) to 50.4 ± 11.7 seconds and chatter from 0.0 to 52.0 ± 16.7 bounces per run. The Ozil-IP was generally more efficient than the Ozil and the Ellips FX more efficient than the Ellips. At optimized values, the Ozil-IP and Ellips-FX were similar. In general, efficiency and chatter were better at 550 mm Hg and at 50% power. The amplitude effect was complex. Efficiency closely correlated with chatter (Pearson r2 = .31, P Conclusions Objective comparison of phacoemulsification efficiency and chatter found that optimized Ozil-IP and Ellips-FX were similar in both parameters and in general, both performed better than preceding technology. The study parameters can significantly affect efficiency and chatter, which strongly correlate with each other. Financial Disclosure Dr. Olson has been a consultant to Abbott Medical Optics, Inc., Becton, Dickinson and Co., and Allergan, Inc., and has received grant support from Abbott Medical Optics, Inc., and Allergan, Inc. No author has a financial or proprietary interest in any material or method mentioned.

Objective comparison of 4 nonlongitudinal ultrasound modalities regarding efficiency and chatter

BACKGROUND To evaluate the effect of varying levels of power on phacoemulsification efficiency using the CENTURION Vision System. METHODS Formalin-soaked porcine lenses were divided into 2-mm cubes; 0.9-mm, balanced tips were used. Torsional power levels were tested from 10% to 100% at 10% intervals. Vacuum was set to 550 mmHg, aspiration to 50 ml/min, and intraocular pressure at 50 mmHg. Efficiency (time to lens removal) and chatter (number of lens fragment repulsions from the tip) were determined. RESULTS Increasing torsional power up to 60% increased efficiency. This effect was linear from 30 to 60% power (R2  = .90; P < 0.05). There were no significant differences in efficiency past 60%. Chatter was highest at 10% power and decreased linearly (R2  = .87; P = 0.007) as power was increased up to 60% power, and chatter did not improve above this power level. CONCLUSIONS Power improved efficiency only up to a 60% power level, and then was negligible. Chatter correlated well with power up to the 60% level, so that as power was increased, chatter decreased. Because there are no additional benefits in efficiency past 60% power, and because chatter is minimal at 60% power, we recommend torsional ultrasound at 60% as the optimal power setting for using the CENTURION System for phacoemulsification.l.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/ceo.12748

Jason D. Jensen

Papers

Objective comparison of 4 nonlongitudinal ultrasound modalities regarding efficiency and chatter

Porcine lens nuclei as a model for comparison of 3 ultrasound modalities regarding efficiency and chatter

Optimum on-time duty cycle for micropulse technology

Determining optimal ultrasound off time with micropulse longitudinal phacoemulsification

Torsional power study using CENTURION phacoemulsification technology.