A Trial to Compare the Laser Treatment (SLT vs. ALT) in Glaucoma Patients (SLTRepeat)

A Randomized Clinical Trial of Selective Laser Trabeculoplasty (SLT) in Open Angle Glaucoma Who Had Been Previously Treated With Complete SLT

Lasers are important therapy in glaucoma. They are a pivotal point in treatment between medical and surgical care. Over the last 10 years a new laser has emerged as the usual laser treatment: Selective laser trabeculoplasty (SLT). SLT works as well as the older laser used: argon laser trabeculoplasty (ALT). However SLT has many theoretical benefits over ALT including causing less damage to the tissue it affects. One of the potential patient centered benefits of this laser is that it may be repeatable. It is even possible that the old laser ALT may be useable after an SLT treatment. This study aims to uncover whether repeat laser is possible after SLT and if so which laser is more effective (ALT vs SLT). The potential of repeating laser therapies may delay surgical treatment and its complications. Also understanding which laser to use will help eye doctors know how to treat their patients at this point of the disease.

Study Overview

• Status: Unknown
• Conditions: Glaucoma
• Intervention / Treatment: Procedure: Argon laser trabeculoplasty; Procedure: Selective laser trabeculoplasty

• Study Type: Interventional
• Enrollment (Actual): 139
• Phase: Phase 3

Contacts and Locations

Study Locations

• Canada
  • Alberta
    • Calgary, Alberta, Canada, T3E 7M8
      • Rockyview General Hospital, University of Calgary
    • Edmonton, Alberta, Canada, T5H 3V9
      • Royal Alexandra Hospital, University of Alberta
  • Nova Scotia
    • Halifax, Nova Scotia, Canada, B3H2R1
      • Eye Care Centre, Dalhousie University
  • Ontario
    • Hamilton, Ontario, Canada, L8G 5E4
      • McMaser University, St. Joseph's Healthcare Hamilton, CAHS Regional Eye Institute
    • London, Ontario, Canada, N6A 4V2
      • Ivey Eye Institute, St. Joseph's Hospital, Western University
    • Toronto, Ontario, Canada, M4N 3M5
      • Sunnybrook Health Sciences Centre, University of Toronto
  • Quebec
    • Montreal, Quebec, Canada, H3A 1A1
      • McGill University, Dept. of Ophthalmology, Royal Victoria Hospital,

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Over age of 18 yo.
• OAG including pigmentary dispersion syndrome and pseudoexfoliation
• OAG has been treated with 360 degrees of SLT
• two sighted eyes,
• willing to participate after being informed of and reading the patient information material.

Exclusion Criteria:

• Narrow angle glaucoma
• Previous glaucoma surgery
• Eye surgery expected in the next 12 months
• Severe corneal disease
• On or anticipated steroid in 6 months
• Pregnant or breast feeding

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Argon laser trabeculoplasty; Up to the year 2005, the vast majority of ophthalmologists used Argon laser trabeculoplasty (ALT) as the mode of laser therapy. ALT is effective but its most significant problem is that its effectiveness decreases with re-treatment since the tissue it targets (the trabecular meshwork) is changed by the laser rendering repeat treatments less effective.	Procedure: Argon laser trabeculoplasty; With Argon laser trabeculoplasty (ALT), thermal energy is used directed towards the Trabecular Meshwork (the site of aqueous drainage from the eye),which causes focal scarring of trabecular meshwork, thus enable fluid drainage more effectively. However, this procedure may not be repeatable since it causes too much damage to the trabecular meshwork.; Procedure: Selective laser trabeculoplasty; Selective laser trabeculoplasty is a relatively newer technology that uses a Nd:YAG laser to target specific cells within the trabecular meshwork. SLT does not cause coagulative damage to the trabecular meshwork, and thus has the advantage of being repeatable.
Active Comparator: selective laser trabeculoplasty; Post 2005, a newer mode of laser therapy, selective laser trabeculoplasty (SLT) has emerged as the standard of care laser. There are many potential advantages to SLT but to date these advantages are only theoretical. The most important potential clinical advantage of SLT is that it causes less damage to the tissue it targets.	Procedure: Argon laser trabeculoplasty; With Argon laser trabeculoplasty (ALT), thermal energy is used directed towards the Trabecular Meshwork (the site of aqueous drainage from the eye),which causes focal scarring of trabecular meshwork, thus enable fluid drainage more effectively. However, this procedure may not be repeatable since it causes too much damage to the trabecular meshwork.; Procedure: Selective laser trabeculoplasty; Selective laser trabeculoplasty is a relatively newer technology that uses a Nd:YAG laser to target specific cells within the trabecular meshwork. SLT does not cause coagulative damage to the trabecular meshwork, and thus has the advantage of being repeatable.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Intraocular Pressure	IOP difference between baseline and 12 month post-laser.	12 months post operatively

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
To compare the IOP lowering effect between the groups at other postoperative visits	IOP difference between baseline, 1hr, 1 wk, and 1, 3, 6 and 12 mon post-laser.	12 months
To compare the visual acuity between the groups at all visits.	VA difference between baseline, 1hr, 1 wk, and 1, 3, 6 and 12 mon post-laser.	12 months
To compare the trabecular meshwork pigmentation between the groups at all visits.		12 months
To compare any adverse events between the two groups at all visits.		12 months
SLT repeatability of long term follow up in glaucoma patients	The follow up time has been extended two more years. Patients will be followed up Q6 months.	36 months after initial enrollment of the primary study

Collaborators and Investigators

• Sponsor: Lawson Health Research Institute
• Investigators: Principal Investigator: William G Hodge, MD, PhD, Lawson Research Institute, Univ. of Western Ontario

Publications and helpful links

General Publications

• Rolim-de-Moura CR, Paranhos A Jr, Loutfi M, Burton D, Wormald R, Evans JR. Laser trabeculoplasty for open-angle glaucoma and ocular hypertension. Cochrane Database Syst Rev. 2022 Aug 9;8(8):CD003919. doi: 10.1002/14651858.CD003919.pub3.
• Hutnik C, Crichton A, Ford B, Nicolela M, Shuba L, Birt C, Sogbesan E, Damji KF, Dorey M, Saheb H, Klar N, Guo H, Hodge W. Selective Laser Trabeculoplasty versus Argon Laser Trabeculoplasty in Glaucoma Patients Treated Previously with 360 degrees Selective Laser Trabeculoplasty: A Randomized, Single-Blind, Equivalence Clinical Trial. Ophthalmology. 2019 Feb;126(2):223-232. doi: 10.1016/j.ophtha.2018.09.037. Epub 2018 Sep 29.

Study record dates

Study Major Dates

• Study Start: November 1, 2012
• Primary Completion (Anticipated): March 1, 2018
• Study Completion (Anticipated): March 1, 2018

Study Registration Dates

• First Submitted: September 11, 2012
• First Submitted That Met QC Criteria: September 18, 2012
• First Posted (Estimate): September 19, 2012

Study Record Updates

• Last Update Posted (Actual): March 6, 2018
• Last Update Submitted That Met QC Criteria: March 5, 2018
• Last Verified: March 1, 2018

More Information

Terms related to this study

• Keywords: laser; glaucoma; ALT; SLT
• Additional Relevant MeSH Terms: Eye Diseases; Ocular Hypertension; Glaucoma
• Other Study ID Numbers: CIHR granted glaucoma RCT