Goals

Purpose

The COAST trial seeks to compare the efficacy and safety of standard versus low energy primary selective laser trabeculoplasty (SLT) in eyes with mild-moderate open-angle glaucoma or high-risk ocular hypertension and to determine the optimal interval and energy for repeat SLT.

Rationale

The Laser in Glaucoma and Ocular Hypertension Trial (LiGHT) recently demonstrated that primary SLT was at least as effective as medical therapy in treating newly-diagnosed glaucoma while avoiding the well-known limitations and inconveniences of daily topical medical therapy. Additional studies have suggested that lower energy SLT provides similar outcomes to standard energy SLT with a potentially more favorable safety profile. Anticipating a paradigm shift to a laser-first approach to glaucoma management, the COAST research team designed this study to clarify the optimal energy and frequency of SLT therapy with the goal of avoiding the need for medical therapy as long as possible. More details on the scientific rationale for the design of the COAST trial can be found here.

Approach

This randomized clinical trial will enroll approximately 635 treatment-naïve patients at up to 20 sites. Patients will receive either standard or low energy SLT, and 12-month success rates will be compared. At 12 months, patients will undergo repeat SLT either annually at low energy or as needed at initially assigned energy, and 48-month success rates will be compared. A synopsis of the study design is available here.

Impact

If we validate an SLT treatment strategy that extends the duration of medication-free disease control, we move one step closer to the possibility of a drop-free lifetime for our patients. Delaying the need for medications by 3, or 5, or 7 years not only confers all the benefits of medication-freedom during this period—which will be all that many patients would need in their lifetimes—it also allows time for the development of safer and more effective drugs dosed infrequently via sustained-release delivery systems, as well as better surgical options, for patients whose lifespans exceed SLT responsiveness.

Thus, a new treatment paradigm consisting of SLT, then sustained-release medications, then surgery, could offer the majority of glaucoma patients the very real possibility of a drop-free lifetime of therapy.