Contrary to current thinking, concurrent topical therapy for glaucoma may augment the intraocular pressure (IOP)-reducing effect of selective laser trabeculoplasty (SLT), according to a new study presented last week at ARVO 2019 in Vancouver. Researchers from San Antonio studied 45 eyes of 39 patients undergoing SLT, under the assumption that coexisting topical therapy might blunt the IOP-reducing effect of SLT. However, data shows IOP reduction in eyes receiving topical therapy was two-fold greater than in those that had no prior history of IOP-reducing therapy, regardless of the number of topical agents applied.

For their study, they divided the participants—undergoing SLT during a four-year interval—into three groups: no medication, one topical anti-glaucoma agent and two or more agents agents. The researchers assessed IOP at pre-treatment baseline and three months post-SLT. While baseline IOP wasn’t significantly different between the three groups, it was post-SLT. Those on no medication had a -3.0 ± -0.7mm Hg reduction, while those on one pre-op medication had a -6.9 ± -1.0mm Hg change, and two more more meds led to IOP reduction of -5.9 ± -1.4mm Hg post-SLT. 

“This finding may be of immediate clinical benefit, but also opens up interesting new physiological questions regarding the effects of topical mediations on the eye’s outflow system for future investigation,” the researchers noted in their study abstract.