Direct SLT Failed to Demonstrate Non-inferiority to SLT in Recent Study Finds

Conventional SLT requires laser treatment delivery with a gonioscopy lens with a coupling medium placed on the cornea, with manual administration of 50 to 100 laser shots. DSLT does not need a gonioscopy lens and coupling medium. Photo: Belkin Vision. Click image to enlarge. A promising alternative to selective laser trabeculoplasty (SLT) known as direct SLT (DSLT) may provide a widely accessible and convenient option across many different clinical settings. The procedure’s efficacy could warrant consideration for first-line therapy in the wake of global glaucoma prevalence increases and the increased recognition of SLT as initial treatment.A prospective study—titled GLAUrious—was conducted in which researchers compared DSLT with conventional SLT in efficacy to reduce intraocular pressure (IOP) in both open-angle glaucoma and ocular hypertension. In their Ophthalmology paper on the work, researchers describe outcomes in patients aged ≥40 years with open-angle glaucoma or ocular hypertension; those involved were randomly assigned 1:1 to be treated with DSLT or SLT.At six months post-op, washout IOP reduction from baseline of the 156 participants without major protocol deviations (81.3%) was 5.5mm Hg (-20.6%) for DSLT and was 6.2mm Hg (-23.6%) for SLT. Between-group difference in mean IOP reduction was -0.7mm Hg, which was less than the noninferiority margin determined at -1.95mm Hg. At 12 months post-procedure, non-washout IOP reduction from baseline of the 161 participants without major protocol deviations (83.9%) was 3.2mm Hg (-12.2%) for DSLT and was 3.2mm Hg (-9.4%) for SLT. Between-group difference in mean IOP reduction was 0.01mm Hg. Safety profiles were comparable among the groups, although non-significant punctate subconjunctival hemorrhage was more frequent following DSLT; ocular adverse events in general were mild and resolved without intervention.  Although the six-month primary endpoint did not achieve statistical non-inferiority, DSLT was well-tolerated and effectively reduced IOP at 12 months. Optimistically, the authors write that “failure to demonstrate noninferiority does not prove inferiority; DSLT remains an effective option in the early treatment paradigm and can be considered as a first-line treatment when SLT is not readily accessible.” One potential rationale offered by the researchers is that the study yielded a “greater than anticipated” standard deviation of baseline IOP measurements, which would have required a sample size of 289 subjects (vs. the 156 evaluated here) to maintain the same statistical power.Despite the result, the authors expand in their paper on how these findings have important implications for worldwide healthcare systems. Early IOP reduction is paramount in glaucoma management, having been linked with sustained IOP control and less frequent glaucoma progression than delayed treatment. However, nonadherence limits long-term effectiveness of topical medications and widespread SLT use is limited by lack of access in certain areas as well as a relatively small number specialists able to perform said procedure. DSLT, they argue, has the potential to overcome each of those constraints.The authors offer the sentiment that DSLT “may also provide a desirable alternative for patients who struggle with adherence to daily eye drop medications or suffer from common side effects, and for those who experience the financial burden of daily glaucoma medication or don’t have access to a glaucoma specialist,” adding that “accessibility is crucial to relieving the burden of glaucoma, and DSLT is a treatment modality that has the potential to significantly change glaucoma management by expanding access to treatment across the world, especially in resource-limited settings.”Click here for the journal source. Gazzard G, Congdon N, Azuara-Blanco A, et al. Randomized non-inferiority trial of direct selective laser trabeculoplasty in open-angle glaucoma and ocular hypertension: GLAUrious. Ophthalmology. May 9, 2025. [Epub ahead of print].