Design and Baseline Characteristics of Participants in the Clarifying the Optimal Application of Selective Laser Trabeculoplasty (SLT) Therapy (COAST) Trial 1.

PRECIS

COAST was designed to investigate alternate approaches to SLT to provide more effective long-term disease control without the need for alternate therapies such as medications or surgery. Methodology and baseline participant characteristics are described.

PURPOSE

To describe the hypothesis and methodology for the ongoing Clarifying the Optimal Application of Selective Laser Trabeculoplasty (SLT) Therapy (COAST) trial 1 and participants' baseline characteristics.

METHODS

COAST Trial 1 is a multicenter randomized trial comparing standard-energy versus low-energy SLT as initial therapy for newly-diagnosed ocular hypertension (OHT) or mild-moderate primary open-angle glaucoma (POAG). The hypothesis is that 12-month survival following low energy SLT will be non-inferior to 12-month survival with standard energy SLT.

RESULTS

When enrollment ceased, 418 participants had been randomized to low-energy (n=203) or standard-energy (n=215) SLT. Demographic and clinical characteristics were similar between groups. Most participants were White (66.5% and 67.9%, respectively) or Black/African American (25.1% and 21.4%, respectively). Qualifying diagnoses were mild POAG (59.6% and 62.1%, respectively), ocular hypertension (32.8% and 30.5%) and moderate POAG (7.6% and 7.4%). Mean optical coherence tomography retinal nerve fiber layer thickness was 81.9 and 82.0 µm, respectively; mean visual field mean deviation was -1.6 dB in both groups. Mean baseline IOP was highest among eyes with ocular hypertension (24.5 and 24.4 mmHg, respectively) and lower in eyes with mild (21.8 and 21.4 mmHg) and moderate POAG (22.0 and 21.0 mmHg).

CONCLUSIONS

COAST is a timely and potentially highly impactful trial that will clarify the optimal utilization of SLT for long-term glaucoma management without the need for alternative therapies such as medications or surgery. The COAST sample closely resembles the population of newly-diagnosed POAG/OHT patients for whom primary SLT would be appropriate, optimizing generalizability of study results when available.