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SLT significantly lowers IOP for glaucoma patients, study finds
Researchers found no adverse effects of selective laser trabeculoplasty in glaucoma patients, according to a recent Journal of Glaucoma study.
Klamann and colleagues also reported that, in conjunction with local therapy, SLT significantly lowered intraocular pressure.
Researchers evaluated 64 eyes of 64 patients with primary open-angle glaucoma that had not been controlled with medical treatment.
Patients underwent comprehensive ophthalmological examinations in which researchers recorded various measurements including IOP. Researchers also graded anterior chamber cells, anterior chamber flare, vitreous cells and vitreous haze according to the Standardization of Uveitis Nomenclature Working Group. Additionally, they measured macular thickness in nine areas with the Spectralis OCT (Heidelberg Engineering) in accordance with the Early Treatment Diabetic Retinopathy Study.
Researchers noted that SLT was "performed 360 degrees with the Trabeculas SLT (ARC Laser), using 95 to 105 spots applied to the trabecular meshwork."
As detailed in the study, participants were treated with topical 1% pilocarpine 1 hour before the surgery. Patients were not treated with corticoids or nonsteroidal anti-inflammatory drugs before or after surgery. Participants continued their antiglaucoma medical treatment after surgery.
Researchers examined the patients 24 hours, 14 days, 6 weeks and 3 months after SLT.
Results showed that IOP at baseline was 19.1 ± 3.972 mm Hg, a number that decreased post-SLT. IOP at 24 hours, 14 days, 6 weeks and 3 months post SLT was 12.9 ± 2.513 mm Hg, 13.2 ± 3.331 mm Hg, 14.1 ± 2.731 mm Hg and 13.9 ± 2.922 mm Hg, respectively. They also showed no statistically significant increase in the retinal thickness from baseline measurements. Researchers also noted a decrease in glaucoma medications, ranging from 15% to 27% 3 months post-SLT.
"The present study shows that SLT treatment produces no clinical relevant inflammation when the eyes were treated in 360 degrees," the authors stated. "Neither inflammation in the anterior chamber nor in the vitreous and retina were found. In this study, no postoperative medication was used, neither nonsteroidal nor corticoids.
"SLT has the potential to effectively lower IOP in eyes with moderate POAG in addition to nonsufficient local therapy," they concluded. “If inflammatory processes are inherent to the mechanism of action of SLT, this may affect the anterior chamber as described in a previous paper, but seems not to affect the vitreous or retina."
Disclosure: The authors have no relevant financial disclosures.
Perspective
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Argon laser trabeculoplasty (ALT) was introduced as a treatment for open-angle glaucoma in the late 1970s and gained acceptance through the Glaucoma Laser Trial 15 years later. More recently, selective laser trabeculoplasty (SLT) has proved to be ‘… a safe and effective initial therapy … equally efficacious as latanoprost … in open-angle glaucoma or ocular hypertension …,’ according to McIlraith.
Katz reported that by targeting pigmented trabecular meshwork, SLT reduces IOP by up to 30%. Klamann and colleagues report a 27% reduction at 3 months in an already relatively low IOP.
The authors also confirm its excellent safely profile, noting that no post-treatment inflammation of any nature (including cystoid macular edema) was encountered, despite treating 360 degrees. Further, SLT dampens diurnal IOP fluctuation, is “nonpreserved,” guarantees treatment compliance, may be repeated and is not adversely impacted by previous or concurrent topical medication use, as Klamann and colleagues demonstrate through its use in OAG previously deemed “insufficiently treated.”
For reasons including efficacy, compliance and medication intolerance, many are rethinking the traditional “medicine before laser before surgery” paradigm and positioning SLT anywhere within the OAG treatment spectrum.
References:
Glaucoma Laser Trial Research Group. The Glaucoma Laser Trial (GLT) and Glaucoma Laser Trial Follow-up Study: 7. Results. Am J Ophthalmol. 1995;120:718-731.
Katz LJ, et al. J Glaucoma. 2012;21:460-468.
McIlraith I, et al. J Glaucoma. 2006;15:124-130.