Pinpointing a first-line treatment for glaucoma

Glaucoma laser procedures are increasingly appealing to patients—particularly those seeking to reduce or avoid the burden of lifelong topical medications. At our hospital, laser therapy plays an essential role across the continuum of glaucoma care.

First-line therapy

For newly diagnosed patients with mild glaucoma, I very often initiate treatment with selective laser trabeculoplasty (SLT) rather than medical therapy. We were early adopters of SLT over 20 years ago, initially using it as an adjunct to drops. Since the publication of the LiGHT trial data, which showed SLT to be as effective as topical medications,¹ the procedure has become a frequent first-line approach.

Figure. With proprietary high-definition gonioscopic and optical coherence tomography imaging, the ViaLuxe Laser System creates a precise aperture through the trabecular meshwork to enable direct aqueous outflow and reduce IOP—all without the need for an incision. (Image courtesy of ViaLase)

For many years, SLT was the only laser-based option available for patients with glaucoma. But today, we are seeing exciting innovations in laser technology that addresses some of the limitations of earlier approaches.

One example is the ViaLuxe femtosecond laser (ViaLase), which I recently had the opportunity to evaluate in a clinical trial. This advanced system enables FLiGHT (femtosecond laser image–guided high-precision trabeculotomy)—a novel, incision-free procedure that creates precise trabeculotomies or drainage channels in the trabecular meshwork without entering the eye surgically. FLiGHT is performed in a clean room setting, eliminating the need for an operating theater and potentially reducing the risks associated with incisional interventions.

With micrometre-level accuracy, the ViaLuxe system integrates real-time high-resolution optical coherence tomography and gonioscopic imaging, allowing unmatched visualisation of the iridocorneal angle (Figure). This imaging enables precise treatment planning and placement, which is critical to achieving consistent outcomes in both phakic and pseudophakic eyes.

Based on my experience, FLiGHT has the potential to become a first-line treatment for glaucoma—particularly if ongoing trials confirm that its IOP-lowering effect is more durable than SLT. In a recently published 2-year study, 82% of eyes achieved a greater than 20% IOP reduction, and 53% of eyes achieved a greater than 25% reduction.² If these results hold over time, FLiGHT could offer a compelling new option for early-stage disease management—one that is incision free and image guided, offering patients earlier intervention without the trade-offs of incisional surgery.

Another relatively new laser is the Voyager DSLT device (Alcon, formerly
Eagle by Belkin Vision). In my short experience, direct SLT (DSLT) is much faster than conventional SLT and does not require gonioscopy. These features make it
convenient for the patient and easy to use for the clinician. The first GLAUrious study found that DSLT’s IOP-lowering effect was comparable to that of conventional SLT at 12 months.³ A longer-term follow-up study is underway. If IOP results are comparable, DSLT could broaden adoption of SLT as first-line or adjunctive therapy.

Adjunctive therapy

All these lasers can also be used as adjunctive therapy. I also use SLT for patients who are on one topical medication but for whom the response is not quite good enough to reach their target IOP. Adding a laser procedure can hopefully get the patient into the normal pressure range and avoid adding a second medication. Another strong clinical case for laser treatment is in patients who are on topical medications but who struggle with compliance or who have ocular surface problems that would benefit from a reduction in topical medications. It is still not fully understood how often laser retreatment can be performed, for whom it is appropriate and what the optimal energy level for repeated procedures should be. The COAST trials are investigating these questions.⁴

We do know that adverse events with laser procedures are quite low, making them a good option for patients because they provide a very good balance of efficacy and safety. Even for patients who are well controlled on drops, I am looking forward to being able to offer new procedures like FLiGHT. We pride ourselves in our department on being early adopters of advanced technology. The femtosecond laser has already demonstrated in other fields of ophthalmology that it is extremely precise and effective; I anticipate that it will have the same advantages in glaucoma but, of course, we have to wait for study results to understand exactly how it will fit into our treatment regimens.

Patients with cataract

For patients with significant cataract, undergoing cataract surgery presents a unique opportunity to perform one of the many minimally invasive glaucoma surgery (MIGS) procedures, including trabecular bypass stents, excimer laser trabeculostomy and other trabecular procedures that improve outflow. Although there are a number of factors, including patient characteristics and comorbidities, that affect which MIGS procedure we choose, cataract surgery is a once-in-a-lifetime chance to further decrease IOP without meaningfully increasing the risk of an already-planned surgery. Typically these patients are early or mild glaucoma cases without significant visual disability and, therefore, we have a responsibility to use the least invasive procedure possible. If the patient has not yet undergone SLT, a laser procedure can be reserved for the future if their glaucoma continues to progress after cataract surgery.

Advanced glaucoma

Laser treatment can also be a good option for the patient with more advanced glaucomatous damage who is not a good candidate for surgery. We have many patients who are too sick or too elderly to undergo more invasive surgery in the operating theater, but who still require better IOP control. Rather that performing an invasive surgery that would add unacceptable risk, laser is a more conservative approach that may be successful in further reducing IOP. Again, more research is needed to understand the comparative performance of SLT, DSLT and FLiGHT in this type of patient.

As laser options continue to expand, I think we will be performing laser surgery even more frequently in all these categories of patients, giving our patients the option to reduce IOP without surgery or topical drops.

References:

1. Gazzard G, Konstantakopoulou E, Garway-Heather D, et al, for the LiGHT Study Group. Selective laser trabeculoplasty versus eye drops for first-line treatment of ocular hypertension and glaucoma (LiGHT): a multicentre randomized controlled trial. Lancet. 2019;393:1505-1516.

2. Nagy ZZ, Kranitz K, Ahmed IK, et al. First-in-human safety study of femtosecond laser image guided trabeculotomy for glaucoma treatment: 24-month outcomes. Ophthalmol Sci. 2023;3(4):100313.

3. Congdon N, Azuara-Blanco A, Solberg Y, et al. Direct selective laser trabeculoplasty in open angle glaucoma study design: a multicentre, randomised, controlled, investigator-masked trial (GLAUrious). Br J Ophthalmol. 2023;107(1):62-65.

4. Realini T, Gazzard G, Latina M, Kass M. Low-energy selective laser trabeculoplasty repeated annually: rationale for the COAST trial. Glaucoma 2021;30(7):545-551.

José María Martínez de la Casa, MD | E: jmmartinezcasa@gmail.com

Martínez is head of the Glaucoma Department at Hospital Clínico San Carlos and professor of ophthalmology at the Universidad Complutense de Madrid in Madrid, Spain. He is principal investigator of ViaLase clinical trial and has received research grants and honoraria from Alcon and Lumenis.