Glaucoma Bonus Issue
February 2025

by Ellen Stodola
Editorial Co-Director

When discussing the use of lasers in glaucoma, Arsham Sheybani, MD, said you first want to separate the options based on incisionless lasers versus lasers that require an incision because those are two very different things. The incisionless lasers include those that perform SLT and direct SLT (DSLT, Alcon) and the femtosecond laser (ViaLase). These, Dr. Sheybani said, shouldn’t be confused with things like ELT or excimer-based lasers that require an incision. “People generally try to lump all these lasers together, but that’s not how it works. Each has its own place.”

Dr. Sheybani thinks that several new technologies will find their place in the glaucoma treatment paradigm as time goes on and more research is done. Awareness of the benefits of SLT for early glaucoma is growing, with increased data to show its efficacy. Dr. Sheybani thinks that something like ELT might be more competitive with goniotomies and stents, while using the femtosecond laser might be somewhat competitive to SLT but may be used before and after incisional glaucoma surgery. How these new options fit in with SLT and other glaucoma procedures will depend on how the technologies develop and are proven through clinical results. 

Gus Gazzard, MD, MBBChir, FRCOphth, was the chief investigator of the LiGHT trial.¹ Looking at 3-year results comparing primary SLT as the first choice, he said it has been shown that laser treatment seems to work better than eye drops at controlling eye pressure and preserving visual field loss. “I would say that everyone should try laser, if the angle is open and there are no contraindications,” he said. 

Prof. Gazzard said that using laser as a first-line treatment is now mandated by clinical guidance in the U.K., and he thinks this is a treatment that should be implemented. “In addition, for the many people who have already been diagnosed and are on eye drops, in mild to moderate or even severe glaucoma, laser can also work very well,” he said. However, he added that the laser may not be enough to be the sole treatment. 

Prof. Gazzard mentioned additional 6-year results comparing SLT and drops, and he said that even if patients had the same overall pressure, the patients who had laser treatment had less deterioration of their visual field. “Their visual field gets worse more slowly, and that’s possibly because laser is better at flattening out the day-to-day variation in eye pressures,” he said. Additionally, Prof. Gazzard said that many people might assume that laser treatment is only for mild disease and won’t work for severe disease, but he doesn’t think this is true. “It won’t be enough on its own for severe disease,” he said. “It still works, but you need something else as well.”

Dr. Sheybani noted that laser treatment could be indicated in various stages of glaucoma, but that’s contingent on which laser you’re talking about. “I think for a new diagnosis and early disease or pre-perimetric disease, it does seem that it should be offered, at least SLT,” he said. Additionally, he likes to consider SLT for moderate to advanced patients who are newly diagnosed. “They’ve never been treated. That’s a patient in whom I think there should be a talk about laser treatment,” he said. 

“The difference when we start discussing disease severity is we lump disease severity, but people with severe disease have often been treated chronically,” Dr. Sheybani said. “The more chronically you’re treated, the less likely it is that some of the treatment modalities, like trabeculectomy, work. There is some thought that this applies to angle procedures; the longer you have been on eye drops, the less likely you will respond to laser or angle surgery,” he said. “Everyone thinks of disease severity, but the other side of the coin is chronicity of treatment that we should be considering.”

Prof. Gazzard said the results of the LiGHT trial have spurred an uptick in SLT, which he thinks will continue. “There’s a clear, rapid increase in the number of SLTs being done around the world,” he said. “In the U.K., that’s true. In other countries, I haven’t seen the data. In some countries, it’s being held back because they don’t have a laser, or doctors aren’t being paid to do laser. I think the uptick will continue as people get increasingly more comfortable with it and the number of patients showing how good the laser is increases.” 

In terms of shifting to standard of care, Prof. Gazzard said that SLT is now standard of care in the U.K. Not everyone gets the treatment, but everyone probably should, he said. “If you ask a room full of glaucoma specialists, three-fourths of them are using SLT as first-line treatment routinely,” he said. “If you ask a room of comprehensive ophthalmologists, the number is lower.”

Prof. Gazzard noted that there may still be some barriers to adopting SLT. The main concern is that it’s not being done enough, but he noted that some barriers vary depending on location and include payment, availability, the time to do the treatment, and who is available to do the treatment. Continued education and continuing to collect and publish data are important. 

“I think a big push that we need to make is those frontline providers, who are doing a huge chunk of the work; they need to make that referral to a comprehensive ophthalmologist or a glaucoma specialist for laser, and I think that’s one of the bigger barriers.”

Arsham Sheybani, MD

Dr. Sheybani said he doesn’t think the increase in SLT procedures has been huge yet, and he attributed this to the technical component with gonioscopy. “It does take time to do SLT, and people might not have the machine,” he said. “Just because the data’s there, I don’t expect it to immediately change how patients are getting treated. I do think that’s unfortunate. It’s such a low-risk procedure, but it does require a technical skill and decent amount of expense to own the laser.”

Dr. Sheybani thinks that at this time, drops are still the first-line treatment in the U.S. because the vast majority of patients are being treated for the first time by optometrists. He expects this to change slowly, but it will require making that initial referral where “you can start a drop but also get that patient over to someone who can do SLT, who can do gonio properly, and give the patient that chance.” 

He said the evidence shows that patients who have laser treatment and repeat treatment do better than those who are just medicated. “I think a big push that we need to make is for those frontline providers, who are doing a huge chunk of the work; they need to make that referral to a comprehensive ophthalmologist or a glaucoma specialist for laser, and I think that’s one of the bigger barriers,” he said, adding that SLT might be first-line treatment for glaucoma specialists and ophthalmologists who are well versed in gonioscopy and who have the machine, but they’re not necessarily the first to see the patient. Most people are going in to get checked for glasses by the optometrist.

Prof. Gazzard discussed other applications for lasers and new lasers being developed for glaucoma, adding that there are a few ways to address this. One way of thinking about it is that laser trabeculoplasty, treating the trabecular meshwork to increase drainage, used to be done with argon laser. It’s now done with SLT and may work via stimulation of trabecular stem cells.

Another area of interest is DSLT, which doesn’t go through a contact lens; it goes directly onto the surface of the eye. Prof. Gazzard said more data is needed on DSLT, but a recent randomized controlled trial was very promising. 

There are other forms of direct laser treatment to the trabecular meshwork. A laser from Carl Zeiss Meditec is a new type of SLT laser, which seems to be working well and is certainly of interest because it may be more reliable, he said. Prof. Gazzard added that more evidence is needed on this technology, but it may be more reproducible. 

There is a procedure where a hole is made with an excimer laser during surgery though the trabecular meshwork, which is more like MIGS, he said, specifically mentioning the ELIOS ab interno excimer laser (Elios Vision, acquired by Bausch + Lomb).

Prof. Gazzard added that there are explorations being done for applications with the femtosecond laser, specifically the femtosecond laser image-guided high-precision trabeculotomy (FLigHT) procedure from ViaLase.

Dr. Sheybani is also looking forward to these products currently in development and further research in the glaucoma laser space. Hopefully DSLT does open up a portal for doctors to be able to offer this laser to patients who are newly diagnosed, he said. 

Dr. Sheybani thinks the ViaLase procedure shows promise. “If there’s a chance to do a goniotomy-level procedure without opening up tissue, that’s very exciting, but we have to wait and see what the data show.” 

Having used the ELIOS laser, Dr. Sheybani noted the safety profile because if you’re in the wrong spot, you can stop instead of continuing to slide and creating more damage. “From a teaching perspective, this might be the safest way to jump into MIGS or trabecular meshwork-based surgery,” he said. 

All of these procedures require technical skills, and as far as being able to do gonioscopy, that’s paramount, Dr. Sheybani said. 

He added that many of these available and upcoming glaucoma laser procedures are accessible to the comprehensive ophthalmologist as well as the glaucoma specialist, and Dr. Sheybani thinks it will be valuable for a variety of surgeons to learn how to perform them. 

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About the physicians 

Gus Gazzard, MD, MBBChir, FRCOphth
Consultant Ophthalmic Surgeon and Director of Surgery
Moorfields Eye Hospital NHS Foundation Trust
London, U.K.

Arsham Sheybani, MD
Associate Professor of Ophthalmology and Visual Sciences
Washington University School of Medicine in St. Louis
St. Louis, Missouri

Reference

1. Gazzard G, et al. Selective laser trabeculoplasty versus eye drops for first-line treatment of ocular hypertension and glaucoma (LiGHT): a multicentre randomised controlled trial. Lancet. 2019;393:1505–1516.

Relevant disclosures

Gazzard: AbbVie, Alcon, Balance Ophthalmics, Bausch + Lomb, Belkin Vision, Carl Zeiss Meditec, Ciliatech, Essential Pharma, Eyetronic, Genentech, Glaukos, Haag-Streit, Iantrek, iStar Medical, Ivantis, Lumenis, McKinsey Consulting, Merck & Co., Nova Eye Medical, Oertli, Quantel/Ellex Lumibird, Rayner, Reichert, Ripple Therapeutics, Santen, Sight Sciences, Thea, Topcon, ViaLase, VISUfarma 
Sheybani: AbbVie, Alcon, Glaukos, Nova Eye Medical

Contact 

Gazzard: g.gazzard@nhs.net
Sheybani: arsham.sheybani@gmail.com