Selective Laser Trabeculoplasty in the Treatment of Ocular Hypertension and Open-Angle Glaucoma: Clinical Review

Outcomes of Micropulse Laser Trabeculoplasty Compared to Selective Laser Trabeculoplasty: A Systematic Review and Meta-Analysis

Purpose

To perform a meta-analysis and systematic review to compare the efficacy and complications of micropulse laser trabeculoplasty (MLT) and selective laser trabeculoplasty (SLT) in adult patients with open-angle glaucoma (OAG) and ocular hypertension (OHT).

Methods

We performed a systematic review utilizing PubMed, Embase, and Scopus, on April 8, 2024. Meta-analyses were performed for the mean change in intraocular pressure (IOP) at one-month, six-month, and one-year follow-up visits, rate of IOP spikes (>5 mmHg increase from the pre-procedure baseline IOP), rate of treatment failure (<20% or <3 mmHg reduction in IOP or requiring additional medications or procedures), and mean change in number of medications.

Results

Six studies, with a total of 593 eyes, were included: 283 underwent MLT, while 310 underwent SLT. A statistically significant difference in the efficacy of MLT versus SLT at one-month and six-month follow-ups was present, with SLT reducing IOP by 0.83 mmHg (95% CI: 0.20, 1.47; P = 0.01) more and 0.55 mmHg (95% CI: 0.02, 1.08; P = 0.04) more than MLT, respectively. At the one-year follow-up, there was no significant disparity in IOP reduction between SLT and MLT (WMD = 0.16; 95% CI: -0.40, 0.71; P = 0.58). There was a significantly lower rate of IOP spikes in the MLT treatment group (RR = 0.37; 95% CI: 0.16, 0.89; P = 0.03). There was no statistically significant difference in the rate of treatment failures (RR = 1.05; 95% CI: 0.68, 1.62; P = 0.84) or number of topical medications reduced (WMD = 0.06; 95% CI: -0.13, 0.26; P = 0.53).

Conclusion

While SLT may offer greater short-term reductions in IOP, it may be associated with more postoperative IOP spikes when compared to MLT. At one-year follow-up, there were no significant differences in IOP reduction or failure rates between the MLT and SLT groups.

180- Versus 360-Degree Selective Laser Trabeculoplasty in Open Angle Glaucoma and Ocular Hypertension: A Systematic Review and Meta-Analysis

PRCIS

This systematic review and meta-analysis found that 360-degree selective laser trabeculoplasty (SLT) is significantly more effective than 180-degree SLT at reducing intraocular pressure at 1-month and 1-year follow-ups without increased serious adverse event risk.

PURPOSE

To determine the efficacy of 180- versus 360-degree selective laser trabeculoplasty (SLT) in adults with open angle glaucoma (OAG) and ocular hypertension (OHT).

METHODS

A systematic review was performed using PubMed, Embase, and Scopus databases, from 1995 to December 30, 2023, for studies comparing 180 and 360-degree SLT in adults with OAG and OHT (PROSPERO ID: CRD42024497832). Meta-analyses were performed to calculate nominal percent and raw reductions in intraocular pressure (IOP) between treatment groups at 1-month, 1-year, and 2-year follow-ups, as well as success rates, defined as a 20% or greater IOP reduction.

RESULTS

Nine studies with 1044 eyes were included; 491 received 180-degree SLT, and 553 received 360-degree SLT. At the 1-month follow-up, 360-degree SLT reduced IOP by 3.45% more (WMD=3.45; 95% CI: 2.02-4.88; P <0.00001) and 0.87 mm Hg more (WMD=0.87; 95% CI: 0.35-1.38; P =0.0010). At the 1-year follow-up, 360-degree SLT reduced IOP by 4.33% more (WMD=4.33; 95% CI: 2.35-6.32; P <0.0001) and 1.15 mm Hg more (WMD=1.15; 95% CI: 0.25-2.04; P =0.01). At 2 years of follow-up, 360-degree SLT reduced IOP by 4.86% more (WMD=4.86; 95% CI: -0.32, 10.0; P =0.07) and 1.25 mm Hg more (WMD=1.25; 95% CI: -0.29, 2.79; P =0.11); however, the difference was not statistically significant. Compared with 360-degree SLT, 180-degree SLT had a significantly lower success rate (OR=0.50; 95% CI: 0.35-0.72; P =0.0002). There was no difference in serious complications between interventions.

CONCLUSIONS

360-degree SLT is more effective than 180-degree SLT at lowering IOP at 1-month and 1-year follow-ups as well as achieving successful IOP control without increased risk of serious complications.

Clinical prediction nomogram for steroid-induced ocular hypertension risk in patients with intravitreal dexamethasone implant

Background

Recognizing the risk factors and understanding the mechanisms underlying steroid-induced ocular hypertension (SIOH) are vital to prevent potent vision loss and ensure the safety and effectiveness of dexamethasone (DEX) injections. The study aimed to develop a novel nomogram for predicting the risk of SIOH and determining safety zones for steroid injections.

Methods

This single-center, retrospective, case-control study included a total of 154 eyes with available measured axial length that had undergone AS-OCT and DEX implantation at the Yonsei University Health System. The eyes were categorized into the SIOH (n = 39) and post-steroid normal IOP (n = 115) groups. We measured intraocular pressure (IOP) for all eyes prior to DEX implantation, at 1 week post-implantation, and at 1, 2, 3, 6, and 12 months thereafter. We used AS-OCT to analyze the trabecular meshwork (TM) height and ocular parameters.

Results

The predictive nomogram, including TM height, yielded an AUC of 0.807 (95 % confidence interval [CI], 0.737-0.877) and demonstrated significantly higher predictive accuracy than that of previous nomograms, which did not consider TM height and had an AUC of 0.644 (95 % CI, 0.543-0.745) (p = 0.031). The calibration plot demonstrated a strong predictive accuracy for a predicted value of approximately 0.4. We established cutoff values to ensure different levels of sensitivity and specificity within the safety zone following DEX implantation.

Conclusion

Our improved nomogram incorporating TM height as a newly identified risk factor, established a safety threshold for intravitreal DEX implantation, helping identify safe individuals from those who require caution.

Mechanism of selective laser trabeculoplasty: a systemic review

Although selective laser trabeculoplasty (SLT) is a recognized method for the treatment of glaucoma, the exact changes in the target tissue and mechanism for its intraocular pressure lowing effect are still unclear. The purpose of this review is to summarize the potential mechanisms of SLT on trabecular meshwork both in vivo and in vitro, so as to reveal the potential mechanism of SLT. SLT may induce immune or inflammatory response in trabecular meshwork (TM) induced by possible oxidative damage etc, and remodel extracellular matrix. It may also induce monocytes to aggregate in TM tissue, increase Schlemm's canal (SC) cell conductivity, disintegrate cell junction and promote permeability through autocrine and paracrine forms. This provides a theoretical basis for SLT treatment in glaucoma.

Optimal Performance of Selective Laser Trabeculoplasty: Results from the Swedish Optimal SLT Multicenter Randomized Controlled Trial

PURPOSE

Selective laser trabeculoplasty (SLT) is a first-line treatment for glaucoma and ocular hypertension. However, due to insufficient comparative evidence in efficacy and safety, several SLT treatment protocols are currently used in practice. The objective of this trial was to compare the clinical outcomes of the 4 most significant SLT variants.

DESIGN

Prospective, multicenter, masked, randomized controlled trial (RCT).

PARTICIPANTS

Four hundred patients with glaucoma or ocular hypertension. The cohort consisted of both treatment-naive patients and patients undergoing glaucoma treatment, at different stages of disease.

METHODS

Selective laser trabeculoplasty was performed with 50 ± 5 laser spots in 180 degrees or with 100 ± 10 spots in 360 degrees. The laser power was titrated to either just below the cavitation bubble level ("standard energy") or to a level producing cavitation bubbles at 50% to 75% of laser applications ("high energy"). Thus, 4 different treatment protocols were included - 180/standard, 180/high, 360/standard, and 360/high. The study adhered as close as possible to regular clinical management, but within a scientific framework.

MAIN OUTCOME MEASURES

Reduction of intraocular pressure (IOP) 1 to 6 months after SLT. The proportion of patients achieving a 20% IOP reduction without any further intervention. Time to glaucoma treatment escalation in a Kaplan-Meier survival analysis.

RESULTS

SLT performed with the 360/high protocol was shown to be superior regarding all primary endpoints. The IOP reduction 1 to 6 months after SLT was 5.4 mmHg in the 360/high group, compared to 3.4, 3.2, and 4.2 mmHg with the 180/standard, 180/high, and 360/standard protocols, respectively (P < 0.001). Furthermore, the success rate after 6 months was significantly higher -58.3%, compared with 30.2%, 29.3%, and 41.7% (P < 0.001). The median time to glaucoma treatment escalation was more than twice as long with 360/high SLT -1323 days, compared to 437 days, 549 days, and 620 days (P < 0.001). Although postoperative discomfort was more frequent with the 360/high protocol, symptoms were generally mild and transient. Adverse events were rare in all groups.

CONCLUSIONS

The magnitude and longevity of SLT results increases substantially if SLT is performed according to the 360/high protocol, without compromising safety. Therefore, we recommend that 360/high SLT be considered as standard treatment.

FINANCIAL DISCLOSURES

The authors have no proprietary or commercial interest in any materials discussed in this article.