Glaucoma
April 2022
by Liz Hillman
Editorial Director
In some glaucoma practices, selective laser trabeculoplasty (SLT) has become a mainstay option at various stages of disease and treatment. However, some ophthalmologists say that despite its diverse utility, SLT adoption has been slow in other practices, and a more recent advancement in related technology could increase adoption.
Thomas Samuelson, MD, said he was a relatively early adopter of SLT, beginning to use it when Mark Latina, MD, and colleagues developed the technology. At the time, Dr. Samuelson said clinicians were excited that SLT seemed less disruptive to target tissue and more user friendly, while equally as efficacious as ALT.
“This user friendliness is now coupled with compelling clinical results and trials, including the LiGHT trial1 as well as the ongoing COAST trial,2 which has prompted the adoption of laser trabeculoplasty as a primary therapy by major glaucoma societies,” Dr. Samuelson said. He added later, “This is a significant development in glaucoma treatment, as now we should consider SLT not only equal to but potentially more efficacious than eye drops. We can inform patients that SLT has a better tolerability profile compared to drops, which are deterred by poor patient adherence, side effects, and high prescription costs. Based on the LiGHT data, patients receiving SLT are also less likely to require secondary surgical intervention.”
Constance Okeke, MD, said she uses SLT often in her practice, with a mix of early, moderate, and advanced glaucoma. She offers it as a first-line treatment to recently diagnosed candidates, she’s used it as an adjunct therapy to patients uncontrolled on drops, and she has offered it to patients who have had previous glaucoma surgery.
“I openly offer SLT as an option and let patients know it is considered a first-line treatment for glaucoma,” Dr. Okeke said. “… I also use it in settings where the patient is on drops and there is need to advance treatment. … I use it in patients who may have already had glaucoma [surgery], such as a MIGS procedure or even a tube shunt or trabeculectomy, if their angle is viable for that. I also often consider it in patients who have allergies or dry eye issues, patients who have issues with compliance.”
Where SLT stands
Despite its utility, Dr. Okeke and Dr. Samuelson said the adoption of it has been slow, compared to other treatments. Dr. Okeke hypothesized that this could be because of the long-time paradigm that drops are the first thing you do to lower IOP before proceeding to the next step, which she said could be laser or surgery.
“I think the uptick has been slow, but it is increasing,” she said, noting that the LiGHT trial has already increased adoption of SLT as a first-line treatment.
Dr. Samuelson speculated on a few reasons for slow SLT adoption. “Before now, specialized training was needed in order to perform SLT, specifically mastering gonioscopy. While gonioscopy should be within the scope of all ophthalmologists, it is widely thought to be underutilized,” he said. Even so, Dr. Samuelson thinks that anyone treating glaucoma should be adept at gonioscopy.
“Another barrier to SLT is chair time to discuss risks, benefits, and alternatives,” he said. “Also, the procedure itself can be time consuming, especially if treating bilaterally. SLT may be considered invasive, at least to patients, because of the need to utilize a focusing lens in direct contact on the patient’s eyes.
“Moreover, some surgeons have continued using ALT, citing that SLT is not necessarily more efficacious. Many ophthalmologists were comfortable staying with ALT because it was a known entity, and they were not convinced of the need to invest in a new laser. Ultimately, despite the downfalls of eye drops, drops are easy to prescribe,” Dr. Samuelson said.
New kid on the block: DSLT
Direct select laser trabeculoplasty (DSLT), which is being developed by Belkin Vision, has the potential to deliver a faster, more patient-friendly SLT process. According to Dr. Okeke, this technology, not yet FDA approved, doesn’t need a gonioprism, which could reduce some of the learning curve and eliminates the potential for discomfort or abrasion from the lens.
“With DSLT, there is no contact lens. You use a beam of light energy directly on the ocular surface tissue and aim this light at the edge of the limbus. The circular beam of light touches the edge of the cornea, and you do this around the limbus, 360 degrees,” she said. “… The energy level used in DSLT is less than it is in SLT, so theoretically that could be better for the tissue. In the studies, which are few, the efficacy of SLT vs. DSLT is the same, and the same type of laser technology is used to do both procedures.”
Dr. Samuelson described the device as “easy to use” and requiring less specialization among care providers to set up the patient. The physician can confirm the settings, alignment, and ultimately deliver the treatment, which he said takes about 1 second.
“As a shorter, more efficient procedure without direct contact, DSLT should result in an improved patient experience compared to SLT and with fewer side effects than eye drops. DSLT lends itself more for use in general ophthalmology practices. Its straightforward delivery system and built-in safety features mean that most comprehensive ophthalmologists can easily adopt the technology,” Dr. Samuelson said.
Discussing SLT with patients
Dr. Okeke said she doesn’t use the word laser in the initial conversation about SLT with patients. She opts instead for the term “light energy treatment,” explaining that she thinks laser carries the connotation of cutting. SLT, she said, uses a gentle laser that doesn’t damage the tissue and cause scarring.
“I’ll tell them how it doesn’t cut or burn but helps to expand the outflow system. I tell them how the procedure is done … usually in the clinic setting, sitting upright. I let them know what to expect during and afterward, what they need to do to take care of their eye. They usually use anti-inflammatory eye drops for a few days. I talk about the effectiveness of the treatment, how long it can last, and the repeatability of it in the future. I also mention the side effect profile, inflammation, and potential of eye pressure spikes and being able to pre-treat that and help avoid it,” Dr. Okeke said.
Dr. Samuelson said when he talks about SLT with patients, he tells them to imagine a medication, a single drop of which controls pressure 80% of the time for a year or two. He said patients generally say, “That would be great, sign me up!”
“I then ask them to imagine that the single eye drop was actually a gentle laser rather than a drop. One application of this treatment, and it might give a year or two, or more in some instances, of pressure control,” he said. “When you present it that way, that’s appealing to a glaucoma patient. Most would say yes to the possibility of coming into the office, putting in an eye drop, and having an 80% chance of having pressure controlled for a year or two. While not directly comparable, this analogy helps patients understand the concept.”
Final considerations
Dr. Okeke said she thinks it’s important for clinicians to make patients more involved in the decision-making process.
“I think it’s imperative for us to let them know what their options are. Those options include SLT or light energy treatment. There are other types of laser treatments. There are diode lasers,” she said. “When I present to them the options of laser treatments and drops and ask which way they want to go, I will have a recommendation, but I open it up to them because sometimes people might be more amenable to new technology while others might be more reserved and want to go with drops. I lean toward their thought processes. … It creates a good doctor/patient relationship.”
Along similar lines, Dr. Samuelson said that while clinicians can make a strong case for laser being the best initial therapy for glaucoma, and he often recommends it, he “stop[s] short of trying to persuade them.”
“If they are set on drops, I do not talk them into laser treatments. But on the occasions that I have the opportunity to initiate treatment, I have a conversation about medical and laser therapy. I explain to patients that traditionally we have considered them equal choices, but there is compelling evidence that SLT may be a better initial treatment. If they are ambivalent, I will provide them a reference to review: the LiGHT trial, in which 11 patients in the drop therapy as initial treatment went on to require invasive glaucoma surgery compared to zero patients in the SLT group. Often with this awareness, they will come around to doing laser first,” Dr. Samuelson said.
About the physicians
Constance Okeke, MD
Assistant Professor
Eastern Virginia Medical School
Norfolk, Virginia
Thomas Samuelson, MD
Minnesota Eye Consultants
Bloomington, Minnesota
References
- 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. The Lancet. 2019;393:1505–1516.
- Realini T, et al. Low-energy selective laser trabeculoplasty repeated annually: Rationale for the COAST trial. J Glaucoma. 2021;30:545–551.
Relevant disclosures
Okeke: None
Samuelson: Belkin Vision
Contact
Okeke: iglaucoma@gmail.com
Samuelson: twsamuelson@mneye.com
