1. Thermal Study of Longitudinal and Torsional Ultrasound Phacoemulsification : Tracking the Temperature of Corneal Surface, Incision and Handpiece Bokkwan Jun MD, John P Berdahl MD, Terry Kim MD* Duke University Eye Center Duke University Eye Center Durham, North Carolina Supported by a research grant from Alcon, Inc., Consultant, Alcon, Inc.*

2. Purpose  To investigate the change and difference in temperature at the corneal surface, incision, and handpiece Two different modalities of ultrasound Two different modalities of ultrasound LongitudinalLongitudinal TorsionalTorsional Two different sizes of incision Two different sizes of incision Standard (2.75mm)Standard (2.75mm) Microincisional (2.2mm)Microincisional (2.2mm)  To observe thermal effect on the wounds Operating microscopy Operating microscopy Scanning electron microscopy (SEM) Scanning electron microscopy (SEM)

3. Methods  Prospective study Twelve human cadaver eyes Twelve human cadaver eyes Four groups of 3 eyes/group Four groups of 3 eyes/group Group 1: 2.75mm, 100% longitudinalGroup 1: 2.75mm, 100% longitudinal Group 2: 2.2mm, 100% longitudinalGroup 2: 2.2mm, 100% longitudinal Group 3: 2.75mm, 100% torsionalGroup 3: 2.75mm, 100% torsional Group 4: 2.2mm, 100% torsionalGroup 4: 2.2mm, 100% torsional  System settings and accessories Fluidics: Vacuum: 300mmHg, Aspiration: 12cc/min, Bottle height: 100cm and simulated On/Off occlusion approx. every 7 seconds Fluidics: Vacuum: 300mmHg, Aspiration: 12cc/min, Bottle height: 100cm and simulated On/Off occlusion approx. every 7 seconds Phacoemulsification time: ~ 40 seconds with full power and instrument manipulation to simulate surgical use Phacoemulsification time: ~ 40 seconds with full power and instrument manipulation to simulate surgical use Tip: Mini-Flared 30° Kelman tip Tip: Mini-Flared 30° Kelman tip Sleeve: MicroSleeve for 2.75mm, UltraSleeve for 2.2mm Sleeve: MicroSleeve for 2.75mm, UltraSleeve for 2.2mm

4.  Thermocamera (ThermaCAM TM, FLIR system, Danderyd, Sweden) (ThermaCAM TM, FLIR system, Danderyd, Sweden) Thermal images were captured every 5 sec Thermal images were captured every 5 sec The temperature of three areas was measured The temperature of three areas was measured 1.Corneal surface 2.Incision 3.Handpiece  Operating microscopy To observe wound burn with OR microscope To observe wound burn with OR microscope (whitening and edema of the wound edge) (whitening and edema of the wound edge)  Scanning electron microscopy (SEM) Methods 123

5.  The average of maximum temperature of incision, handpiece and corneal surface in each group Results Max temperature (°C) IncisionHandpieceCorneal surface Group 1 (2.75mm, 100% longitudinal)45.943.739.5 Group 2 (2.2mm, 100% longitudinal) 47.744.741.9 Group 3 (2.75mm, 100% torsional)33.227.425.5 Group 4 (2.2mm, 100% torsional)37.230.229.8

6. Results Group 1 Group 1 (2.75mm, 100% longitudinal) Group 2 Group 2 (2.2mm, 100% longitudinal) Group 1 Group 1 (2.75mm, 100% torsional) Group 1 Group 1 (2.2mm, 100% torsional)  Comparison of Thermal images at maximum temperature

7. Results  Temperature changes of corneal surface, incision and hand piece Group 1 Group 1 (2.75mm, 100% longitudinal) Group 3 Group 3 (2.75mm, 100% torsional) Group 2 Group 2 (2.2mm, 100% longitudinal) Group 4 Group 4 (2.2mm, 100% torsional)

8.   Comparison of incision temperature with 2.75mm and 2.2mm incision Results Group 1 (2.75mm, 100% longitudinal) vs Group 2 (2.2mm, 100% longitudinal) Group 3 (2.75mm, 100% torsional) vs Group 4 (2.2mm, 100% torsional) (p=0.002) (p<0.001)

9.   Comparison of incision temperature between longitudinal and torsional groups Results Group 1 (2.75mm, 100% longitudinal) vs Group 3 (2.75mm, 100% torsional) Group 2 (2.2mm, 100% longitudinal) vs Group 4 (2.2mm, 100% torsional) (p<0.001)

10. Results  Operating microscopy Group 1 and 2 (longitudinal US groups) Wound burn (whitening and edema of the wound edge) was observed in 6/6 Incision temperature was 43~45 ℃ when the first sign of wound burn was observed Group 3 and 4 (torsional US groups) No wound burn was evident in 0/6

11. Results (SEM, endothelial view)  SEM images demonstrating wound gap of inner surface and partial loss of Descemet’s membrane Group 1 Group 1 (2.75mm, 100% longitudinal) Group 2 Group 2 (2.2mm, 100% longitudinal) Group 3 Group 3 (2.75mm, 100% torsional) Group 4 Group 4 (2.2mm, 100% torsional)

12. Conclusions  Incision temperature Can be influenced by ultrasound modality. Can be influenced by ultrasound modality. Was significantly lower in torsional ultrasound as compared to longitudinal ultrasound. Was significantly lower in torsional ultrasound as compared to longitudinal ultrasound. To a lesser extent, smaller incisions may also increase incision temperature, but not to a significant degree. To a lesser extent, smaller incisions may also increase incision temperature, but not to a significant degree.  The combination of torsional ultrasound and small incisions A safe way to decrease the risk of wound burn in patients with dense cataracts. A safe way to decrease the risk of wound burn in patients with dense cataracts.