To investigate the effect of topical prostaglandin analogue use on the efficacy of selective laser trabeculoplasty (SLT) intraocular pressure (IOP) lowering in patients with open-angle glaucoma.This retrospective study included 123 consecutive patients who underwent 180 degrees SLT for the first time. Eyes were grouped into those that received prostaglandin analogues before and after SLT (n=74) and those that did not (n=49). The main outcome measure was IOP lowering after SLT. Success was defined as > or =20% reduction in IOP without further glaucoma intervention.There was no significant difference in IOP lowering at 6 months post-laser between the prostaglandin and non-prostaglandin groups (3.9+/-4.8 vs 4.6+/-3.6 mm Hg, P=0.43). Long-term SLT success rates were also not significantly different between the treatment groups (Kaplan-Meier survival analysis, P=0.68). IOP lowering at 6 months was similar in eyes that received no glaucoma medications, monotherapy with or without a prostaglandin analogue, or combination therapy with or without prostaglandin analogues (P=0.81). Logistic regression analysis showed that various patient characteristics including age, sex, type of glaucoma, previous glaucoma surgery, and other glaucoma risk factors did not predict a successful SLT outcome. However, higher pre-operative IOP was found to predict SLT success (odds ratio=1.12, 95% CI=1.02-1.24, P=0.02).The IOP lowering efficacy of SLT is not influenced by the use of topical prostaglandin analogues.