Don Davis, MD, Peter Ness, MD, Surekha Maddula, MD, Liliana Werner, MD, PhD, Nick Mamalis, MD

1. Don Davis, MD, Peter Ness, MD, Surekha Maddula, MD, Liliana Werner, MD, PhD, Nick Mamalis, MD Analysis of Intraoperative Capsular Trauma Induced by a New Single-Use Polymer Irrigation/Aspiration Tip During Posterior Capsule Polishing The authors have no financial interest in this product This project was supported in part by a grant from Alcon and by an unrestricted grant from Research to Prevent Blindness to the Department of Ophthalmology at the University of Utah

2. Background Posterior capsule rupture is a serious complication of cataract surgery. Roughly one-third of posterior capsule ruptures occur during the irrigation/aspiration stage of phacoemulsification1. Although posterior capsular polishing does not influence rates of posterior capsule opacification2, anterior capsular polishing can decrease rates of anterior capsule opacification/fibrosis3 and capsular contraction4. Because of this effect, some have advocated the use of routine capsular polishing with implantation of multifocal and other premium intraocular lenses that are extremely susceptible to decentration from mild capsular contraction5. The single-use polymer tip studied here was manufactured to decrease posterior capsular trauma during irrigation/aspiration and capsular polishing.

3. Purpose A B To compare the safety and capsular friendliness of a new single-use polymer irrigation/aspiration (I/A) port with a standard metal I/A port in a Miyake cadaver eye model. A. Photomicrograph (20X) of metal I/A tip used in the Pathology laboratory for research purposes. Note the small metal discontinuity on the proximal irrigation port opening that is common to reusable metal I/A tips. B. Photomicrograph (20X) of single-use polymer I/A tip without sleeve. Note the smooth irrigation port opening. The tip is distensible with moderate pressure, and the aspiration port edges are regular and smooth.

4. Material/Methods • One eye of each cadaver pair was treated with a standard metal I/A tip (OD) while the contralateral eye was treated with a single–use polymer I/A tip (OS). • Nine pairs of cadaver eyes were prepared using the Miyake/Apple technique under open sky for better capsular visualization. • Following capsulorrhexis, and nucleus expression by hydrodissection, cortex was removed by each respective I/A tip. • The aspiration port was then occluded on the posterior capsule and swept in several 2-3 mm arcs in order to induce either capsular rupture or zonular dehiscence. B A Miyake view of posterior capsule cleaned with metal (A) or silicone polymer tip (B). Note the striae in the posterior capsule as the aspiration port is occluded and swept in 2-3mm arcs.

5. Material/Methods II • If the posterior capsule/ zonular apparatus remained intact, the vacuum was increased in a stepwise fashion to a maximum of 600 mmHg. • Flow rate and bottle height were fixed. • The eyes were assessed by subjectively documenting zonular stretching/ dehiscence and objectively measuring maximum vacuum withstood without capsular rupture. Due to the small sample size and combination of two variables into one graded scale (with emphasis on maximum vacuum), the data was analyzed with the Wilcoxon Ranked Sum test for non-parametric data. Miyake view of posterior capsule occluded within the aspiration port of the I/A tip. Note zonular compromise.

6. Results: Table of Study Data *Eye Numbers with the same color represent eye pairs †Data was discarded because of tear in posterior capsule prior to study inception §Zonular Stretching from 0-4+ was noted in the study. No zonular dehiscence was noted.

7. Results Summary • Ten of 18 eyes were able to tolerate a maximum I/A vacuum of 600 mmHg (3/9 metal tips and 7/9 polymer tips) without structural compromise (zonular dehiscence or posterior capsular rupture). • Metal I/A tips induced 5 capsular tears and one zonular dehiscence • Polymer I/A tips induced 2 capsular tears. • There is a statistically significance difference between the metal and polymer tips with respect to structural compromise (p= 0.015). Miyake view of posterior capsule after capsular rupture was induced by a metal I/A tip.

8. Conclusion • Cortical removal and capsular polishing with the new single-use polymer I/A port is a safe alternative to using metal I/A tips and may induce less trauma than metal I/A tips. • Utilization of single-use I/A tips is also suitable to reduce the likelihood of toxic anterior segment syndrome (TASS)6. Anterior segment photo of a patient with TASS – Post-operative Day 1 from phacoemulsification with intraocular lens placement.

9. References 1. Gimbel H, Sun R, Ferensowicz M, Penno EA, Kamal A. Intraoperative Management of Posterior Capsule Tears in Phacoemulsification and Intraocular Lens Implantation. Ophthalmology. 2001;108:2186–92. 2. Shah SK, Praveen MR, Kaul A, Vasavada AR, Shah GD, Nihalani BR. Impact of anterior capsule polishing on anterior capsule opacification after cataract surgery: a randomized clinical trial. J Cataract Refract Surg. 2010 Feb;36(2):208-14. 3. Sacu S, Menapace R, Wirtitsch M, Buehl W, Rainer G, Findl O. Effect of anterior capsule polishing on fibrotic capsule opacification: three-year results. J Cataract Refract Surg. 2004 Nov; 30(11):2322-7. 4. Tadros A, Bhatt UK, Karim A, Zaheer A, and Thomas PW, Removal of lens epithelial cells and the effect on capsulorhexis size. J Cataract Refract Surg. 2005 Aug; 31(8):1569–74. 5. Ossma IL, Galvis A, Vargas LG, Trager MJ, Vagefi MR, McLeod SD. Synchrony dual-optic accommodating intraocular lens. Part 2: pilot clinical evaluation. J Cataract Refract Surg. 2007 Jan;33(1):47-52. 6. Mamalis N, Edelhauser HF, Dawson DG, Chew J, LeBoyer RM, Werner L. Toxic Anterior Segment Syndrome. J Cataract Refract Surg. 2006 Feb;32(2):324-33.