Predictors of Success in Selective Laser Trabeculoplasty

Abstract

Purpose: Selective laser trabeculoplasty (SLT) is a common procedure to lower intraocular pressure (IOP) in patients with glaucoma. However, reports are conflicting regarding what factors contribute to SLT success. The purpose of this study was to determine predictors of SLT success.

Design: Retrospective case series.

Participants: All patients treated with SLT between January 1, 2012, and June 30, 2018.

Methods: Baseline, demographic, procedural, and ophthalmic examination data were recorded at the time of first SLT treatment. Intraocular pressure and medication data were recorded at all follow-up visits.

Main outcome measures: Selective laser trabeculoplasty success was defined as IOP decrease of 20% or more from baseline at the 3-month, 6-month, and 12-month follow-up visits. Eyes were considered to have failed and were censored when additional SLT or glaucoma surgery was performed. Patients were excluded if they had less than 3 months of follow-up.

Results: A total of 997 eyes from 677 patients were included in the study. Mean age was 70.2±11.5 years. Selective laser trabeculoplasty success was achieved in 227 eyes (22.8%), whereas 770 eyes (77.2%) did not meet success criteria. Intraocular pressure before SLT was 21.9±5.2 mmHg while taking 2.0±1.2 medications in eyes with successful SLT, compared with 19.0±5.0 mmHg (P < 0.0001) while taking 2.1±1.3 medications (P = 0.52) in eyes with SLT failure. At the 1-year follow-up, mean IOP in eyes with SLT success was 14.7±3.2 mmHg with 2.0±1.2 medications, compared with 16.3±4.7 mmHg (P = 0.008) with a mean of 1.9±1.3 medications (P = 0.37) in eyes with SLT failure. Eyes with SLT success more often showed greater angle pigment (P = 0.03). Age, glaucoma severity, total SLT power, type of glaucoma, severity of glaucoma, visual field mean defect, and retinal nerve fiber layer thickness were not found to correlate with success. No difference was found between the rate of success based on treatments before SLT, whether surgical or medical.

Conclusions: In this large cohort of eyes undergoing SLT, greater IOP and angle pigment before SLT correlated positively with SLT success. Age, total SLT power, severity of glaucoma, and prior treatments were not associated with SLT success or failure.