Nepafenac-Assisted Mydriasis During Cataract Surgery in a Rabbit Model

1. Nepafenac-Assisted Mydriasis During Cataract Surgery in a Rabbit Model Michael K. Yoon, MD and Stephen McLeod, MD UCSF Laser Vision Center, San Francisco, CA

2. Financial Disclosures M. Yoon Alcon (D,E) My research is fully or partially funded by a company that makes/develops/provides ophthalmic products or services. My travel expenses have been reimbursed, paid in full or subsidized, by a company that makes/develops/provides ophthalmic products or services. S. McLeod Alcon (D) My research is fully or partially funded by a company that makes/develops/provides ophthalmic products or services.

3. Introduction • Safe cataract surgery requires excellent visualization throughout the surgical procedure, as complication rates are related to pupil size and quality of visualization during surgery. • Inadequate mydriasis produces an increased risk of surgical trauma, postoperative inflammation,and posterior capsule rupture.1-3 • NSAIDs are commonly used to maintain mydriasis during cataract surgery.4 1Stewart R et al. Clin Ther. 1999 Apr;21(4):723-32. 2Drolsum L et al. Acta Ophthalmol (Copenh). 1994 Feb;72(1):21-6. 3Goodman DF et al. Ophthalmic Surg. 1989 Feb;20(2):132-40. 4Schalnus R et al. Ophthalmologica. 2003 Mar-Apr;217(2):89-98.

4. Purpose • To compare the effectiveness of the NSAID nepafenac 0.1% to that of flurbiprofen and placebo at achieving and maintaining pupil dilation in a rabbit model of cataract surgery.

5. Methods • Eighteen adult pigmented rabbits were randomized to 3 treatment groups (n=6 each): nepafenac 0.1%, flurbiprofen 0.03%, and placebo. • Cataract surgery was performed on both eyes of the rabbits in randomized order by a surgeon who was blinded to group assignment. • Treatment with NSAID or placebo was administered 1 day prior (3 times daily) and immediately prior to surgery (every 5 minutes x 3). • 10% phenylephrine was administered to all rabbits immediately prior to surgery (every 5 minutes x 3). • Phacoemulsification was performed in standard fashion. • Pupil measurements were recorded using calipers immediately before and after surgery. • A two-tailed student’s t-test was used to compare mean pupil diameters between each group.

6. Baseline Pupil Size

7. Preoperative Pupil Size * *P < 0.001, nepafenac vs. flurbiprofen P < 0.005, nepafenac vs. placebo The nepafenac group had a significantly larger mean pupil size preoperatively than either the flurbiprofen group or the placebo group.

8. Postoperative Pupil Size * *P < 0.05, nepafenac vs. flurbiprofen P < 0.001, nepafenac vs. placebo The nepafenac group had a significantly larger mean pupil size immediately after surgery than either the flurbiprofen group or the placebo group.

9. ANCOVA Analysis of Postoperative Pupil Size Difference ANCOVA controls for preoperative pupil size, group effect, and fellow eye P = 0.009 P = 0.21 P = 0.046

10. Other Variables • No statistically significant differences between nepafenac and control or between nepafenac and flurbiprofen for: • Time between first dilation drop and incision • Total surgical time • Phacoemulsification time or average power • Preoperative IOP, postoperative IOP, or change in IOP

11. Conclusions • The use of nepafenac 0.1% starting 1 day prior to cataract surgery in rabbits was more effective at achieving maximal preoperative pupil mydriasis (P < 0.005) than an identical regimen using either flurbiprofen 0.03% or placebo. • Nepafenac maintained postoperative mydriasis significantly better than placebo, even when controlling for preoperative pupil size, group effect, and fellow eye