EFFECT OF EYE COLOR ON SELECTIVE LASER TRABECULOPLASTY Elaine M. Miglino Arusha Gupta, MD Lawrence F. Jindra, MD

Financial Disclosures 1st and 2nd authors have no financial disclosure. 3rd author has independently conducted and financed clinical research study presented and provides technical advice and consultant services to Lumenis Corporation.

Introduction Selective Laser Trabeculoplasty (SLT) uses a Q-Switched frequency-doubled (532 nm) Nd:YAG laser which targets melanocytes in the pigmented trabecular meshwork.1,2 When treated with SLT, a primarily biologic response is induced in the trabecular meshwork which involves the release of cytokines that trigger macrophage recruitment and other changes leading to IOP reduction.2 It treats the meshwork without causing any thermal or coagulative damage to surrounding structures.1,2 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.

Objective and Methods To examine the effect of eye color (blue or brown) on SLT, in decreasing intraocular pressure (IOP) in patients with glaucoma. A retrospective chart review was performed on 137 eyes treated with SLT over 5 years; eyes were grouped as blue or brown. Two-tailed paired t-test and ANOVA were used to compare maximum pre- and post-SLT IOP.

Results: Blue Eyes 53 blue eyes were treated with SLT for glaucoma; mean follow-up was 388 days. IOP decreased from a mean of 18.5 to 13.6 mm Hg; this represents a 26% decrease in IOP. Data were significant with P < 0.05.

Results: Brown Eyes 84 brown eyes were treated with SLT for glaucoma; mean follow-up was 306 days. IOP decreased from a mean of 19.5 to 13.3 mm Hg; this represents a 32% decrease in IOP. Data were significant with P < 0.05.

Data Blue Eyes Brown Eyes Number of eyes (n) 53 84 Mean follow-up (days) 388 306 Pre-SLT IOP (mm Hg) 18.5 19.5 Post-SLT IOP (mm Hg) 13.6 13.3 IOP change (mm Hg) 4.9 6.2 % ↓ IOP 26% 32% P-value < 0.05

Eye Color vs Decrease in Post-SLT IOP Data Eye Color vs Decrease in Post-SLT IOP % Decrease in IOP Blue Eyes (n = 53 eyes) Brown Eyes (n = 84 eyes)

Summary Mean Post-SLT Reduction in IOP: Brown Eyes 32% Blue Eyes 26% The results were significant with P < 0.05.

Conclusion In this series, SLT significantly lowered mean IOP more in brown eyes and less in blue eyes, suggesting a direct relationship between eye pigment and post-SLT reduction of IOP in patients with glaucoma.