Topical NSAIDs May Reduce Laser Glaucoma Treatment’s Effectiveness

Although SLT patients may experience discomfort after the procedure, topical NSAID treatments may interrupt the IOP-lowering mechanism of the treatment.

Selective laser trabeculoplasty (SLT) does not benefit from postprocedural topical application of nonsteroidal anti-inflammatory drugs (NSAID), according to a study published in Acta Ophthalmologica. In fact, the study shows NSAIDs have the potential to reduce the laser glaucoma treatment’s efficacy.

“For years, there has been concern that anti-inflammatory treatment after SLT may reduce treatment efficacy,” according to researchers. “This was based on the hypothesis that the mechanism of action of SLT includes inflammatory mediators and mechanisms, such as secretion of interleukins and recruitment of monocytes. The current study is the first to consistently demonstrate that in clinical practice.”

The study looked at 192 eyes of 192 patients, with 96 being given topical NSAIDs drops after SLT (mean age, 71.8±10.8 years; 46% women; using 0.84±1.0 glaucoma medications) and 96 patients who were not given drops considered a control group (mean age, 73.4±9.7 years; 48% women; using 0.99±1.0 glaucoma medications). All patients had a baseline intraocular pressure (IOP; measured on the day of SLT) of at least 18 mm Hg. Their IOPs were monitored weekly for 3 to 12 weeks postoperatively with Goldmann applanation tonometry. All SLT treatments were performed in 270˚ to 360˚ degrees, with at least 75 laser spots. 

Patients in the NSAID group experienced a mean relative IOP reduction (defined as reduction relative to baseline IOP, expressed as a percentage) of 17.5±13.0% (95% CI, 14.9–20.1), whereas those in the control group experienced a mean IOP reduction of 21.8±14.8% (95% CI, 18.8–24.8). That 4.3 percentage point difference is statistically significant, the study authors explain (P =.033, t-test).

The mechanism of action of SLT includes inflammatory mediators and mechanisms.

The researchers also conducted extensive subgroup analyses, including a multiple linear regression analysis — which shows NSAID treatment can be a negative predictor of IOP reduction after adjustment for covariates (P =.023) — and Kaplan–Meier survival analysis regarding time to treatment escalation — which shows a longer median time to treatment escalation in patients who did not received NSAIDs, although that finding was not statistically significant.

While patients commonly experience low-grade pain or discomfort in the days following the intraocular-pressure lowering laser treatment, adverse events are rare, making postoperative topical NSAID regimen a clinical consideration. Prior research shows conflicting data on whether NSAID pain management aids in SLT’s IOP-lowering effect, or detracts from it — at least 1 piece of research, the 2019 Steroids After Laser Trabeculoplasty for Glaucoma (SALT) trial (ClinicalTrials.gov Identifier: NCT00981435), suggests a significantly greater mean IOP reduction after 12 weeks in patients treated with steroidal or NSAID drops after SLT, compared with a placebo. However, the authors of this study say that the prior research had “a slight imbalance between groups, with more patients treated with SLT in 180 degrees in the placebo group (45%, compared to 25% and 37%), [that] may have had an impact on [the study’s] results.”

Limitations of this research include its retrospective study design and its lack of randomization, possibly leading to systematic selection bias.

References:

Dahlgren T, Ayala M, Zetterberg M, et al. The impact of topical NSAID treatment on selective laser trabeculoplasty efficacy. Acta Ophthalmol. Published online October 18, 2022. doi:10.1111/aos.15276