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Study yields no difference in IOP between SLT, drugs as initial therapy
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After 9 to 12 months of follow-up, the difference in mean IOP achieved by patients with glaucoma randomized to either selective laser trabeculoplasty or medical therapy was not statistically significant, according to a study.
The prospective, multicenter trial included 127 eyes of 69 patients with open-angle glaucoma or ocular hypertension. The mean IOP at baseline was 24.5 mm Hg in the SLT group and 24.7 mm Hg in the group that received medical therapy, which consisted primarily of prostaglandin analogues.
At the last of six follow-up visits over 1 year, the SLT group attained a mean IOP in both eyes of 18.2 mm Hg, for an overall reduction of 6.3 mm Hg. The final follow-up results were comparable for the medical group, in which mean IOP in both eyes was 17.7 mm Hg, for an overall reduction of 7 mm Hg.
“For a long time now, we have been trying to figure out where SLT fits in the treatment paradigm for glaucoma,” lead study author L. Jay Katz, MD, told Ocular Surgery News. “Traditionally, SLT has always been used after failing medical therapy. But is this the best place to position SLT for every patient?”
The study was published in the Journal of Glaucoma.
The U.S.-based Glaucoma Laser Trial in the 1980s and 1990s compared argon laser trabeculoplasty to medical treatment for initial therapy.
“That study showed laser to be a very reasonable first-line option, at least in some patients,” Katz said. “But there were a lot of criticisms of the study, including how it was designed. As a result, the study never truly impacted how clinicians practiced. The adoption rate for first-line therapy remained low.”
The current study was fashioned in a slightly different manner to make the results more applicable, Katz said.
“Similar published studies, including from Israel, Canada and the United Kingdom, have shown that laser as a first-line option is comparable to our best class of medication, at least during the first year, in lowering IOP. So our study was confirmatory rather than surprising,” Katz said.
Katz said that the medical community as a whole is conservative, and it is difficult for clinicians to embrace novel treatment options.
“Still, there has been a gradual evolution of using laser trabeculoplasty earlier and earlier, before waiting for all the medications to fail,” he said. “Our study should bolster confidence in recommending SLT as an alternative to medical therapy for a lot of patients.”
Medical therapy for glaucoma poses challenges.
“It costs patients money and requires them to use the medication every day for the rest of their lives with potential side effects, so there is concern about adherence or compliance. But with laser, there is no issue of compliance,” Katz said.
By final follow-up, 11% of study eyes had received SLT re-treatment, and 27% of eyes required additional medication.
Katz, who along with Wills Eye Institute colleagues performed 20 of the initial SLT procedures, said only patients with early to moderate disease were candidates for the trial.
“SLT may be inadequate for advanced glaucoma cases where one wishes to quickly decrease IOP,” he said. “So for people with more advanced disease, it is probably better to initiate drug therapy, sometimes multidrug therapy, then consider SLT or surgery depending on how much further the IOP needs to be reduced.”
Clinicians should be flexible in discussing treatment options with patients.
“Leave SLT as a reasonable choice for certain patients as initial therapy,” Katz said. – by Bob Kronemyer