Floral Park Ophthalmology Winthrop University Hospital Six-Year Cumulative Experience of Selective Laser Trabeculoplasty as Repeat Therapy in Patients with Glaucoma ASCRS 2009 Joseph A. Donnelly Hofstra University Elaine M. Miglino Floral Park Ophthalmology Lawrence F. Jindra, MD Columbia University Winthrop University Hospital Kristina E. Fittipaldi Hofstra University 1st Author has no financial disclosure 2nd and 3rd Coauthors have no financial disclosure 4th Coauthor has independently conducted and financed clinical research study presented and was a consultant to Lumenis Corporation with the past year

Introduction Selective Laser Trabeculoplasty (SLT) uses a Q-Switched frequency-doubled (532 nm) Nd:YAG laser, which targets melanocytes in the trabecular meshwork1,2 SLT treatment induces a biologic response in the trabecular meshwork, which involves the release of cytokines that trigger macrophage recruitment and other changes, leading to IOP reduction2 SLT treats the meshwork without causing any thermal or coagulative damage to surrounding structures1,2 1. Latina MA, et al. Selective targeting of trabecular meshwork cells: in vitro studies of pulsed and CW laser interactions. Exp Eye Res. 1995;60:359-372. 2. Latina MA, et al. Q-switched 532-nm Nd:YAG laser trabeculoplasty (selective laser trabeculoplasty): a multicenter, pilot, clinical study. Ophthalmology. 1998;105:2082-2090.

Purpose and Methods Purpose Methods To examine the cumulative incidence of repeat therapy over six years with Selective Laser Trabeculoplasty (SLT) for patients with glaucoma. Methods Retrospective chart review was performed on 1595 eyes from a consecutive case series of 2056 eyes treated with SLT over six years. Eyes were divided into those treated with primary and secondary therapy, then into subgroups of 0-2, 2-4, and 4-6 years of follow up, and then were randomly selected for analysis. The rates of repeat and times until repeat were recorded and analyzed.

Results (Repeat Rates) Eyes which had SLT as primary treatment, with follow up of 0-2, 2-4, and 4-6 years had repeat rates of 5%, 10%, and 9%, respectively. Eyes which had SLT as secondary treatment, with follow up of 0-2, 2-4, and 4-6 years had repeat rates of 40% , 60%, and 46%, respectively. Years of Follow up Primary Patients Repeat Rates (%) Secondary Patients Repeat Rates (%) 0-2 5 40 2-4 10 60 4-6 9 46 Results were significant with p < 0.01

Results (Time to Repeat) Eyes which had SLT as primary treatment, with follow up of 0-2, 2-4, and 4-6 years, average days to repeat were 325, 1005, and 1837 days, respectively. Eyes which had SLT as secondary treatment, with follow up of 0-2, 2-4, and 4-6 years, average days to repeat were 298, 901, and 1619 days, respectively. Years of Follow up Primary Patients Time to Repeat (Days) Secondary Patients Time to Repeat (Days) 0-2 325 298 2-4 1005 901 4-6 1837 1619 Results were significant with p < 0.01

Discussion The Glaucoma Laser Trial Established efficacy of laser trabeculoplasty in lowering IOP in previously untreated glaucoma patients1 The Ocular Hypertensive Treatment Study & The Early Manifest Glaucoma Trial Established efficacy of early and effective treatment to preserve long-term visual function in glaucoma patients2,3 Our findings build on these studies and suggest repeat rates were significantly less in eyes treated with SLT as primary therapy than in eyes treated with SLT as secondary therapy. Further study with controlled clinical trials is indicated. 1. The GLT Research Group. GLT. Ophthalmology. 1990;97:1403-1413. 2. Kass MA, et al. OHTS. Arch Ophthalmol. 2002;120:701-713. 3. Heijl A, et al. EMGT. Arch Ophthalmol. 2002;120:1268-1279.

Conclusion In this series over the long-term: Repeat rates after primary SLT at all time intervals examined, were significantly less than repeat rates after secondary SLT. Time to repeat after primary SLT at all time intervals examined, was significantly more than time to repeat after secondary SLT. Results were significant with p > 0.01.