Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. A Randomized Clinical Trial of Selective Laser Trabeculoplasty Versus Argon Laser Trabeculoplasty in Patients With Pseudoexfoliation Shefalee S. Kent, MD, FRCSC,* Cindy M. L. Hutnik, MD, PhD, FRCSC,* Catherine M. Birt, MD, FRCSC,w Karim F. Damji, MD, FRCSC,z Paul Harasymowycz, MD, FRCSC,y Francie Si, MD, MSc,* William Hodge, MD, PhD, FRCSC,* Irene Pan, MSc,* and Andrew Crichton, MD, FRCSC8 Purpose: To evaluate the efficacy of selective laser trabeculoplasty (SLT) versus argon laser trabeculoplasty (ALT) in lowering the intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension secondary to pseudoexfoliation. Design: Multicentered randomized clinical trial. Participants A total of 76 eyes from 60 patients with pseudoexfo- liation and uncontrolled IOP were recruited from 5 Canadian academic institutions. Patients with prior laser trabeculoplasty, ocular surgery within 6 months, previous glaucoma surgery, an advanced visual field defect, current steroid use, and monocular patients were excluded. Methods: Eyes were randomized to receive either 180-degree SLT or 180-degree ALT by a nonblocked randomization schedule stratified by center. Main Outcome Measurement: The primary outcome was the change in IOP at 6 months versus baseline and secondary outcomes included change in number of glaucoma medications after laser. Baseline variables included age, sex, angle grade, angle pigmenta- tion, and number of glaucoma medications. Results: Of the 76 eyes, 45 eyes received SLT and 31 eyes received ALT. The overall age was 72.9 years (65% females). The baseline IOPs in the SLT and ALT groups were 23.1 and 25.2 mm Hg, respectively (P = 0.03). The IOP reduction 6 months after SLT was  6.8 mm Hg. Key Words: SLT, ALT, RCT, glaucoma, pseudoexfoliation (J Glaucoma 2013;00:000–000) P seudoexfoliation (PXF) glaucoma is the most common identifiable form of secondary open-angle glaucoma accounting for 25% of all open-angle glaucomas world- wide. 1 First described in 1917, it is a generalized basement membrane disease of the extracellular matrix characterized by the progressive, stable deposition of abnormal fibrillar material in various intraocular and extraocular tissues. 2 It is most commonly seen in certain ethnic groups (eg, Scandi- navians, Bantus of South Africa, the Nahavo Indians, and the Aboriginals of Australia), and is most notable for the challenge it presents in managing intraocular pressure (IOP). Clinically, all tissues of the anterior segment of the eye are involved with deposition of white dandruff. Clin- ically, all tissues of the anterior segment of the eye are involved with deposition of white dandruff-like material on the lens, iris and ciliary epithelium, and trabecular mesh- work. The etiology of open-angle glaucoma associated with PXF is a blockage created within the trabecular meshwork from pseudoexfolative material and pigment, and an obstruction of Schlemm canal, narrowing of the canal and ultimately the collapse of its walls. 1 There are usually no symptoms until visual field defi- cits characteristic of advanced glaucoma develop. Treat- ment for PXF includes glaucoma medications, laser trabeculoplasty, and incisional surgery. Two types of laser trabeculoplasties are generally utilized: argon laser trabe- culoplasty (ALT) and selective laser trabeculoplasty (SLT). ALT is thought to use thermal energy directed toward the trabecular meshwork causing focal scarring of trabecular beams and thereby opening intervening and adjacent spaces. 3 The inflammatory cytokines induce structural changes and allow repopulation of the trabecular meshwork with dividing trabecular epithelial cells from untreated areas, which are more effective in phagocytosis and produce a dif- ferent composition of extracellular matrix with improved outflow facility properties. In 1995, SLT was introduced as an alternative choice to ALT. 4 SLT uses a nonthermal laser to achieve similar results without causing visible damage to the trabecular meshwork structures. 5,6 The goal of this randomized clinical trial (RCT) was to compare the effectiveness of SLT versus ALT in lowering IOP up to 6 months after treatment in patients with PXF who have open angles. The results will be useful in guiding clinical practice choices. METHODS Patients were recruited consecutively from 5 academic ophthalmology institutions across Canada (the University of Western Ontario, the University of Calgary, the Uni- versity of Toronto, the University of Ottawa, and the University of Montreal) to participate in this prospective RCT. Each institution had 1 glaucoma specialist as local Received for publication October 12, 2012; accepted May 12, 2013. From the *Department of Ophthalmology, University of Western Ontario, London; wDepartment of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON; zDepartment of Ophthalmology, University of Alberta, Edmonton; 8Department of Ophthalmology, University of Calgary, Calgary, AB; and yDe- partment of Ophthalmology, University of Montreal, Montreal, QC, Canada. Disclosure: The authors declare no conflict of interest. Reprints: Cindy M. L. Hutnik, MD, PhD, FRCSC, Department of Ophthalmology, University of Western Ontario, Ivey Eye Institute, SJHC 268 Grosvenor Street London, ON, Canada N6A 4V2 (e-mail: cindyh@sjhc.london.on.ca). Copyright r 2013 by Lippincott Williams & Wilkins DOI: 10.1097/IJG.0b013e31829e55e4 ORIGINAL STUDY J Glaucoma  Volume 00, Number 00, ’’ 2013 www.glaucomajournal.com | 1