1. Corneal Endothelial Cell Loss Results in a Comparison of Longitudinal vs. Torsional with Vacuum Demand Interjected Longitudinal (IP) Phacoemulsification in Eyes with Hard Cataracts James A. Davison, MD FACS Wolfe Eye Clinic Marshalltown, Iowa ASCRS Poster 2011 Alcon Paid Consultant No Financial Interest

2. Background Torsional ultrasound appears to use less metered ultrasonic energy and keep nuclear material on its tip more constantly creating a more efficient process for the removal of average nuclei than longitudinal ultrasound. However, torsional ultrasound is not efficient in the removal of very firm nuclei so longitudinal ultrasound must be used in those cases. Interjected longitudinal ultrasonic segments into the torsional ultrasound stream (IP) creates a process which seems to combine the efficiency of torsional and the effectiveness of longitudinal ultrasound. In firm nuclei only, how does IP compare with longitudinal ultrasound with respect to corneal endothelial cell loss?

3. LOCS III NC 3.7 Torsional LOCS III NC 3.7 Soft Nucleus. Nuclear material is most efficiently withdrawn by higher vacuum which increases after larger torsional ultrasonic tip oscillations bore the tip into nuclear material occluding its aperture.

4. LOCS III NC 3.9 Torsional LOCS III NC 3.9 Firm Nucleus. Torsional ultrasonic tip oscillation allows the tip to bore into new nuclear material occluding its aperture. Increasing tip oscillation and high vacuum create a “dynamic occlusion” encouraging firmer material to become deformed as it is emulsified allowing it to be drawn through the aperture and shaft. The torsional movement and vacuum keep new material presenting to the tip without bouncing it away but the process is slower with firm nuclear material and does lead to eventual release of the sustained high vacuum level.

5. LOCS III NC 3.8 IP LOCS III NC 3.8 Medium Nucleus. Torsional ultrasonic tip oscillation and vacuum create aperture occlusion as the tip bores into nuclear material. When 90% of the 400 mmHg preset vacuum trigger is reached, 10 msec pulses of longitudinal ultrasonic oscillation are interjected. They alternate with 90 msec segments of torsional oscillation. This alternation creates an instantly more effective emulsification of material in the tips aperture and shaft and chugs it through more efficiently. The briefer process avoids prolonged periods of high vacuum experienced with dynamic (material moving) or static (material stalled) occlusion and the problems attendant with high vacuum release.

6. Previous Study Our similar 2010 Study of 18 cases using Obliquely Horizontal Divide and Conquer DuoVisc technique* Konan Robo SP 9000 with 50 central cell manual counting method 3 months after surgery demonstrated corneal endothelial cell density changes of - 4.4% + 4.4 for longitudinal and + 2.8% + 3.9 for IP Equivalency demonstrated but ECD reliability and comparisons threatened by low case numbers and cell counting technology * Presented at the ASCRS 2010 by James A. Davison, MD

7. New Study Methods 40 cases LOCS III NC > 3.8 Corneal ECD comparison –Preoperative and 3 months postoperative –Konan NSP-9900 non-contact camera –Automated 100+ central cell counting method Phaco software-tip motion random assignment for quadrant removal –Continuous longitudinal –Continuous torsional with interjected longitudinal segments –Programmed on demand at 90% of 400 mm Hg, 10 msec segments alternating with 90 msec torsional segments, 1.0 longitudinal/torsional ratio Single surgeon, DuoVisc, Same Obliquely Horizontal Oriented Divide and Conquer technique

8. Debulk Corners in Situ (Longitudinal) Horizontal Aperture Orientation (IP) Firm Nucleus Horizontal Divide and Conquer

9. Centralize Fragments and Remove with Aperture Oriented Obliquely Horizontal (IP) Firm Nucleus Horizontal Divide and Conquer

10. New Study Results Results pending Spring 2011

11. Thank you James A. Davison, MD FACS Wolfe Eye Clinic Marshalltown, Iowa