Micropulse Laser Trabeculoplasty (MLT) Versus Selective Laser Trabeculoplasty (SLT) for Treatment of Open Angle Glaucoma

Phase IV Study of Micropulse Laser Trabeculoplasty Versus Selective Laser Trabeculoplasty for Treatment of Open Angle Glaucoma

The purpose of this study is to evaluate the effectiveness of a new laser (called Micropulse Laser Trabeculoplasty or MLT) in the treatment of glaucoma compared to the conventional laser presently used which is called selective laser trabeculoplasty or SLT. Both lasers (SLT and MLT) are used as standard of care in the treatment of open angle glaucoma.

Study Overview

• Status: Completed
• Conditions: Open Angle Glaucoma
• Intervention / Treatment: Device: Micropulse Laser Trabeculoplasty; Device: Selective Laser Trabeculoplasty

Detailed Description

Glaucoma is the 2nd leading cause of blindness worldwide and affects over 2.5 million Americans over the age of 40. It is thought that elevated intraocular pressure causes damage to the optic nerve fibers which leads to silent vision loss in glaucoma. Therefore, the primary approach to managing this disease process is through intraocular pressure reduction with a) topical drops that decrease intraocular fluid production or increase fluid outflow, b) laser therapy to the outflow structures in the eye (trabecular meshwork) to increase fluid egression, c) or incisional surgery with or without placement of setons to create a new pathway for fluid outflow. When medical therapy has been maximized or patients do not tolerate topical therapy, laser trabeculoplasty is common applied to achieve further intraocular pressure reduction. There are two types of laser therapies: argon laser trabeculoplasty (ALT) and selective laser trabeculoplasty (SLT). The former involves applying laser to create outflow pathways in the trabecular meshwork (TM) and induces thermal damage to the TM. The latter selectively applies energy which induces inflammatory restructuring of the TM without creating a burn. Studies have shown comparable results between the two treatment modalities with SLT offering the advantage of repeatable treatment. Studies have also shown laser trabeculoplasty to be comparable to the effect of topical drops in intraocular pressure reduction. Side effects for both types of laser trabeculoplasty include post procedure intraocular pressure elevation and intraocular inflammation which is treated with topical drops after the procedure.

This study aims to evaluate the effectiveness of micropulse laser trabeculoplasty in intraocular pressure reduction in patients with open angle glaucoma as compared to conventional selective laser trabeculoplasty. Secondary aims would be to determine whether its reduction is comparable to that of topical intraocular pressure lowering drops, length of therapeutic intraocular pressure reduction, and incidence of side effects commonly encountered with traditional laser trabeculoplasty including intraocular inflammation and intraocular pressure spikes.

• Study Type: Interventional
• Enrollment (Actual): 81
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • District of Columbia
    • Washington, District of Columbia, United States, 20037
      • George Washington University Medical Faculty Associates

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Patients of any ange age
• Diagnosis of open angle glaucoma who have not had recent changes in their medication regimen.

Exclusion Criteria:

• Patients with active neovascularization of the angle, angle closure glaucoma, angle recession, or anterior uveitis

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Micropulse Laser Trabeculoplasty; Patient's randomized to MLT would be treated with the following settings: 300 micron spot size, 0.3 second duration, 15% duty cycle, and 1000 milliWatt power. They would be treated with confluent laser spots across the entire 360 degrees of the trabecular meshwork. Each patient would receive pre-treatment with a drop on iopidine or brimonidine to prevent post-operative intraocular pressure (IOP) spikes as per standard pre-laser trabeculoplasty protocol.	Device: Micropulse Laser Trabeculoplasty; Other Names: MLT; Laser
Active Comparator: Selective Laser Trabeculoplasty (SLT); Patient's randomized to SLT would be treated with the following settings: 400 micron spot size, 0.3 second duration, and 1.00 milliWatt (mW) power. They would be treated with confluent laser spots across the entire 360 degrees of the trabecular meshwork. Each patient would receive pre-treatment with a drop on iopidine or brimonidine to prevent post-operative IOP spikes as per standard pre-laser trabeculoplasty protocol.	Device: Selective Laser Trabeculoplasty; Other Names: SLT; Laser

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Intraocular Pressure Reduction	evaluate the effectiveness of micropulse laser trabeculoplasty in intraocular pressure reduction in patients with open angle glaucoma as compared to conventional selective laser trabeculoplasty The aim of this study was to prospectively compare the efficacy, safety, and tolerability of selective laser trabeculoplasty (SLT) vs micropulse laser trabeculoplasty (MLT) in reducing intraocular pressure (IOP) in open-angle glaucoma patients.	within 6 weeks to 3 months after the laser procedure is completed
Intraocular Pressure (IOP) Reduction Comparison Between MLT and SLT	Intraocular pressure (IOP) reduction comparison between MLT and SLT	24-52 week interval
Intraocular Pressure (IOP) Reduction	Percentage of participants with a decrease of greater or equal to 3 mmHg intraocular pressure from baseline	52 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Measurement of Pain/Inflammation by a Pain Scale Post Laser Treatments From Micropulse and Selective Laser Trabeculoplasty.	The measurement of pain commonly encountered with traditional laser trabeculoplasty including intraocular inflammation will be measured and compared between both lasers (SLT vs. MLT). Standardized pain survey (scale of 0=none and 10=severe) Higher number, the more pain was being experienced by subject	at the time of treatment and at 1 week following the laser procedure

Collaborators and Investigators

• Sponsor: David Belyea
• Investigators: Principal Investigator: David Belyea, MD, George Washington University

Publications and helpful links

General Publications

• Detry-Morel M, Muschart F, Pourjavan S. Micropulse diode laser (810 nm) versus argon laser trabeculoplasty in the treatment of open-angle glaucoma: comparative short-term safety and efficacy profile. Bull Soc Belge Ophtalmol. 2008;(308):21-8.
• Juzych MS, Chopra V, Banitt MR, Hughes BA, Kim C, Goulas MT, Shin DH. Comparison of long-term outcomes of selective laser trabeculoplasty versus argon laser trabeculoplasty in open-angle glaucoma. Ophthalmology. 2004 Oct;111(10):1853-9. doi: 10.1016/j.ophtha.2004.04.030.
• Fea AM, Bosone A, Rolle T, Brogliatti B, Grignolo FM. Micropulse diode laser trabeculoplasty (MDLT): A phase II clinical study with 12 months follow-up. Clin Ophthalmol. 2008 Jun;2(2):247-52. doi: 10.2147/opth.s2303.

Study record dates

Study Major Dates

• Study Start: August 1, 2013
• Primary Completion (Actual): July 1, 2017
• Study Completion (Actual): July 24, 2017

Study Registration Dates

• First Submitted: September 30, 2013
• First Submitted That Met QC Criteria: September 30, 2013
• First Posted (Estimated): October 8, 2013

Study Record Updates

• Last Update Posted (Estimated): June 13, 2023
• Last Update Submitted That Met QC Criteria: May 19, 2023
• Last Verified: May 1, 2023

More Information

Terms related to this study

• Keywords: LASER; GLAUCOMA; MICROPULSE; TRABECULOPLASTY; OPEN ANGLE; INTRAOCULAR PRESSURE
• Additional Relevant MeSH Terms: Eye Diseases; Ocular Hypertension; Glaucoma; Glaucoma, Open-Angle
• Other Study ID Numbers: 041310