Laboratory Evaluation of a Next Generation Transversal Ultrasound System

1. Laboratory Evaluation of a Next Generation Transversal Ultrasound System Mark E. Schafer, Ph.D. President and Principal Scientist, Sonic Tech, Inc. Chief Technology Officer and VP, R&D, Sound Surgical Technologies, LLC I am a consultant to several phaco companies, and have received research funding for this work Contact email: marks@sonictech.com

2. Purpose & Outline Purpose: • To provide baseline comparative data for different phaco devices, specifically for a newly introduced transversal system – AMO Whitestar Signature with Ellips FX • Testing focused on Clinically Relevant settings Outline: • Measurement results using several previously studied approaches: • Needle Shaft Temperature Rise (non-frictional) • Cutting Effectiveness into artificial lens material • Acoustic Output • Compare results with another non-longitudinal phaco device – Infiniti Torsional Ozil • Discussion and Conclusion

3. Standard “Longitudinal” phaco is an in/out motion “Torsional” or “T-phaco” uses a twisting motion of the tip rather than a longitudinal motion (only one of the two modes can operate at a time, therefore the need to switch back and forth) “Transverse” or “Ellips” uses a combination of side to side and in/out simultaneously; may be used with either straight or bent tips What are the technologies/modes?

4. Thermal Measurements: Materials & Methods • Full computer control and acquisition of thermal images for analysis • Irrigation and aspiration flows balanced to mimic closed system in eye: Fluid rate precisely measured at 30ml/min, at temperature of 22±0.5°C • Systems run for 5 second foot pedal time; results scaled to 0.5 or 1 sec • High resolution thermal imaging (FLIR) camera records thermal image of hub, needle, and tip • An open fluid chamber allows the entire length of the needle to be examined • Cup designed so that fluid would only touch tip, to allow aspiration, but not interfere with thermal imaging • Inner cutaway cup maintained fluid at desired level; outer cup held overflow • Hub, shaft, and tip tracked and separately recorded

5. Thermal Testing: Results • Thermal imaging showed distributed heat sources for transversal mode included both the hub region and the shaft • In longitudinal mode, the heat source was predominantly in the hub transition region • Hyperpulse (WhiteStar) modes reduced the thermal rise • Analysis was scaled to the one second on-time point, as shown in the graph by the vertical line • Multiple experiments were conducted under the same conditions and the results averaged

6. Thermal Testing: Results • The one-second temperature rise for Elllips at typical clinical settings of 25-50% amplitude, in a WhiteStar 6-12 mode, ranged from 2.1 to 3.5°C • In Longitudinal mode, for the same WS mode, the temperature rise was lower, on the order of 0.5 to 1.0°C • The difference is due to the location of the heat source • Note that this does not account for friction between the shaft and the sleeve, which would be significantly higher in longitudinal mode than in transversal or torsional

7. Measuring Cutting: Materials & Methods • Custom cutting force system • Full computer control of motor and high resolution acquisition of position and force data for analysis • Simulated lens target material • Constant force (60g weight), measure displacement as a function of time • Fluid rates maintained at 30cc/min • 10 second experiment; initial 2 seconds to establish position baseline; systems then run for 8 second foot pedal time • Systems operated over a range of clinically relevant/recommended settings

8. Cutting Effectiveness: Results • Multiple test runs conducted for each measured condition • Penetration measured and analyzed to find a cutting rate in terms of millimeters per second • Ellips cutting rates varied from 0.35mm/sec at 25% setting to 1.7mm/sec at the 50% setting

9. Acoustic Output: Materials & Methods • Acoustic measurement system captures both the low frequency (handpiece drive) energy as well as the cavitational energy • Rotational fixture allows mapping the distribution of energy, which relates to the motional direction of the tip • Data can correlate to cutting efficiency depending upon cavitation readings

10. Acoustic Output: Results • Drive energy levels match theory for longitudinal; for transversal, less acoustic energy is generated because of the acoustic dipole pattern, as confirmed by angular data • Difference between theory and measurement represents low frequency ultrasonic energy converted into Cavitation • In Transveral mode, Cavitation is generated in region around the tip including the sides, rather than just at the front, as is the case for Longitudinal • The front panel setting which denotes the start of Cavitation action matches the setting which demonstrates increased cutting effectiveness

11. Comparison to Torsional • Transversal mode produces less internal heating, with improved cutting performance, in comparison with Torsional, at clinically relevant/recommended amplitude settings • This is due in part because Transversal motion preserves some longitudinal component • Transversal mode can also be used with straight tips, which permits more choices for the surgeon; bent tips would be expected to have slightly better cutting performance, and higher acoustic output, without significantly higher thermal rise

12. Discussion / Conclusion • This study provided an initial investigation into this new phaco modality, which was only introduced into the market this year • Additional work will be required to examine all the interdependent configuration possibilities, such as drive setting/mode and tip size and configuration • Preliminary data suggest that Transversal mode demonstrates superior characteristics in terms of the balance of safety and efficacy, relative to other non-longitudinal modalities • Ultimate goal is to provide users with a consistent set of metrics by which to compare different systems, permitting a better understanding of energy input and clinical outcome