Direct selective laser trabeculoplasty in glaucoma: insights from the GLAUrious study

Introduction

Glaucoma is a leading cause of irreversible vision loss worldwide (1). Traditionally, treatment relied on starting with topical medications, followed by laser or surgery. However, over the last decade the treatment paradigm for glaucoma has shifted, particularly after the Laser in Glaucoma and Ocular Hypertension (LiGHT) trial, which demonstrated that selective laser trabeculoplasty (SLT) is a more effective and cost-efficient first-line alternative to topical medications in the treatment of open angle glaucoma (OAG) and ocular hypertension (OHT) (2,3). Despite this evidence, widespread adoption of SLT has been limited by the time required for the procedure, which can be a challenge in busy clinical settings where time constraints are already a concern. More recently, a novel approach, direct selective laser trabeculoplasty (DSLT), has emerged (4). Unlike conventional SLT, DSLT is an automated, noncontact, image-guided technique that delivers laser energy through the limbus without gonioscopy. By removing procedural barriers inherent to conventional SLT, DSLT aims to streamline the workflow while maintaining efficacy.

Discussion

The GLAUrious study is the first randomized multicenter noninferiority trial comparing DSLT with conventional SLT in patients with OAG or OHT and assessed intraocular pressure (IOP) reduction at the 6-month and 12-month periods (5). Although the primary endpoint of statistical noninferiority at 6 months was not met due to greater than anticipated variability, both treatment groups demonstrated comparable IOP reductions, when compared to the non-washout baseline, and similar medication reduction profiles through 12 months (5). These findings prompt an important discussion regarding how automated laser delivery may influence the future of glaucoma care delivery.

Although DSLT did not meet the noninferiority criteria, it still achieved clinically meaningful IOP reductions. At 6 months, the average washout IOP reduction was 5.5±0.5 mmHg (−20.6%) for DSLT, compared to 6.2±0.5 mmHg (−23.6%) for conventional SLT (5). The authors set a noninferiority margin of −1.95 mmHg, noting that IOP differences within 2 mmHg are often due to measurement variability and unlikely to be clinically significant (5). However, factors such as loss to follow-up and increased variability in IOP measurements can widen the confidence interval, leading to the results exceeding the margin and causing failure to meet the noninferiority threshold. According to the authors, the failure to reach statistical significance is largely attributed to greater than expected variability in IOP response, rather than true clinical inferiority (5). Notably, more than 15% of patients after being assigned to their treatment groups were lost to follow-up at both timepoints, resulting in reduced statistical power, particularly at 6 months (5). Despite this, the difference in IOP reduction between the two treatments was small, less than 1 mmHg, making it unlikely to be clinically meaningful (5).

From a clinical standpoint, DSLT’s appeal lies in its ability to improve workflow efficiency. Conventional SLT requires gonioscopic lens placement, precise visualization, and operator experience to deliver treatment across the trabecular meshwork (6,7). DSLT, by contrast, is automated and noncontact, potentially reducing procedure time and operator dependence (8). This simplification may allow for the delivery of treatment to a greater number of patients.

The issue of accessibility is increasingly relevant. Global glaucoma prevalence continues to rise, and many health systems already struggle to meet demand for routine care (9-11). Simultaneously, guideline recommendations favoring SLT as first-line therapy have increased procedural demand. This demand may be further increased, depending on the findings of the current ongoing COAST (Clarifying the Optimal Application of SLT Therapy) trial, which is seeking to investigate the utility of annual repeated SLT (12,13). Technologies that allow efficient scaling of effective treatments may therefore become central to future glaucoma service delivery.

The safety data from this study was overall reassuring, with adverse events being largely mild and transient. Aside from the higher rate of punctate subconjunctival hemorrhage with DSLT, complication profiles were comparable across the two treatment modalities. There were no serious adverse events in the DSLT group. However, important unanswered questions remain regarding long-term safety, durability beyond 1 year, and the repeatability of treatment, which is especially relevant in light of the ongoing COAST trial.

An important procedural distinction between conventional SLT and DSLT relates to the ability to titrate treatment energy. During conventional SLT, direct gonioscopic visualization of the trabecular meshwork allows the operator to titrate laser energy in real time, typically guided by the appearance of champagne bubbles, enabling adjustment according to angle pigmentation and tissue response (2,14). In contrast, DSLT delivers a standardized energy profile circumferentially without direct visualization of the angle (4). This difference may be clinically relevant in eyes with heavily pigmented trabecular meshwork, where lower energy settings may be preferred to reduce the risk of excessive inflammatory response or post-procedural IOP spikes. Similarly, in patients with pseudoexfoliation glaucoma, careful examination of the angle and titration of energy is important (15). Notably, the GLAUrious study population was composed predominantly of White participants (98%), a group generally less likely to exhibit heavy trabecular pigmentation, raising the question of whether outcomes and safety profiles would be similar in more diverse populations where trabecular meshwork pigmentation patterns differ (13). Given that DSLT is applied transsclerally, the presence of conjunctival melanosis near the limbus could potentially influence its efficacy. However, the impact of significant melanosis in these areas remains unclear, and further research is needed to better understand how it might affect treatment outcomes.

Another consideration is that the medication washout requirements may have led to a selection bias for patients with milder disease who could safely tolerate temporary cessation of therapy. Real-world efficacy in patients with more advanced disease remains unclear and requires further investigation. The GLAUrious study required medication washouts, and it remains unclear how well DSLT would perform in patients who are simultaneously using topical medications (13). While the findings suggest promising potential as a first-line therapy for mild and moderate disease, its effectiveness in more advanced cases, where patients remain uncontrolled despite being on several topical medications, needs further research. Additionally, although DSLT does not require a gonioscopic lens on the eye, it does require the use of a speculum, which may also cause discomfort for the patient. This is also important to consider given the concern that speculum use could contribute to the development of ptosis.

Finally, economic considerations are likely to influence adoption. While procedural simplification may lower the costs of delivering treatment, factors such as device acquisition, reimbursement policies, and integration into practice workflows remain critical determinants of uptake (16). The DSLT device, for instance, is generally more expensive and incurs a per-treatment fee, which may impact its cost-effectiveness depending on patient volume (13). The per-treatment fees may make it more difficult to gain widespread adoption among ophthalmologists; however, this model is becoming more common in other ophthalmic subspecialties, such as retina, where the photobiomodulation device for age-related macular degeneration also carries similar fees (17). Future health economic analyses comparing DSLT, SLT, and long-term medication therapy will be valuable in guiding clinical decision-making.

Conclusions

The GLAUrious study demonstrated that DSLT achieved IOP reductions and a safety profile broadly similar to conventional SLT, although statistical noninferiority at 6 months was not achieved. Clinical outcomes through 12 months suggested comparable effectiveness between approaches, but uncertainty remains regarding longer term durability, repeatability, and effectiveness in more diverse patient populations. Automated, noncontact approaches like DSLT could potentially simplify treatment delivery, but further studies, including those with longer follow-up durations and cost-effectiveness analyses, are needed to determine its role in routine clinical practice.

Acknowledgments

None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, Annals of Translational Medicine. The article has undergone external peer review.

Peer Review File: Available at https://atm.amegroups.com/article/view/10.21037/atm-2026-1-0036/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://atm.amegroups.com/article/view/10.21037/atm-2026-1-0036/coif). The authors have no conflicts of interest to declare.

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