Randomized Prospective Study of Selective Laser Trabeculoplasty (SLT) Versus Argon Trabeculoplasty (ALT) in Patients With Pseudoexfoliation Glaucoma and Ocular Hypertension (SLT)

Randomized Multicentre Prospective Study of Selective Laser Trabeculoplasty (SLT) vs. Argon Trabeculoplasty (ALT) in Patients With Pseudoexfoliation Glaucoma and Ocular Hypertension

Multi-center, prospective, randomized, controlled clinical trial to compare selective laser trabeculoplasty (SLT) and Argon laser trabeculoplasty (ALT) in pseudoexfoliation glaucoma and ocular hypertension patients. IOP will be recorded, at baseline, 6 weeks, 6 months and 1 year after the laser procedure.

Study Overview

• Status: Completed
• Conditions: Ocular Hypertension; Exfoliation Syndrome
• Intervention / Treatment: Procedure: SLT; Procedure: ALT

Detailed Description

This study derives from a clinical observation that laser treated eyed with PXF glaucoma may have a similar long-term response rates when either ALT or SLT is performed. Some authors have considered that there is a risk of IOP elevation in the immediate post laser period with ALT or SLT as a complication to be related to denser angle pigmentation (20,48). (46) No long-term analysis comparing response rates of both laser treatments in these types of patients has been done.

Primary objective is to determine which laser therapy has more IOP lowering effect as primary or adjunctive treatment in eyes diagnosed with ocular hypertension and glaucoma associated to PXF. Response rates will be compared between groups at long-term.

Secondary objective is to determine the relationship between the type of laser therapy performed and angle pigmentation, number of applications, and amount of energy used with age, number and type of medication used post laser and phakic status.

• Study Type: Interventional
• Enrollment (Actual): 25
• Phase: Phase 3

Contacts and Locations

Study Locations

• Canada
  • Alberta
    • Calgary, Alberta, Canada, T2V1P9
      • Rockyview General Hospital Eye Clinic
  • Ontario
    • London, Ontario, Canada, N6A 4V2
      • St. Joseph's Health Care London Eye Clinic
    • Ottawa, Ontario, Canada, K1H 8L6
      • University of Ottawa Eye Institute
    • Toronto, Ontario, Canada, M4N 3M5
      • Dr. C Birt
  • Quebec
    • Montreal, Quebec, Canada, H1V 1G5
      • Montreal Glaucoma Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 16 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Only patients with clinical evidence of unilateral or bilateral open angle pseudoexfoliation ocular hypertension (IOP > 22mmHg) or glaucoma (Evidence on Humphrey 30-2 or Goldmann of nerve fiber layer damage) with uncontrolled IOP, over 18 years of age, and are willing to participate in the study will be included. If increased IOP is bilateral then the worst eye will be treated.

Exclusion Criteria:

• Patients will be excluded if they have evidence of any glaucoma other than pseudoexfoliative open angle, if the trabecular meshwork cannot be seen in 360 degrees, if they had previous laser therapy ALT or SLT, if they have advanced visual field defect (split fixation or a scotoma within 10 degrees fixation), taking any systemic or topical steroids, have had any previous ocular surgery (glaucoma or cataract extraction included) or laser within the previous six months, if they are monocular patients, if they have any corneal disease precluding the angle evaluation and treatment, or if they had ocular trauma.

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: selective laser trabeculoplasty (SLT)	Procedure: SLT; All eyes will be treated using a commercially available Q-switched Nd:YAG laser (Coherent Selecta 7000, Coherent Inc., Palo Alto , CA, USA) calibrated by the manufacturer. On the day of treatment, IOP will be measured, then one drop of Apraclonidine 1% or Brimonidine 0.2% and pilocarpine 1% or 2% will be instilled. Before the patient is seated at the laser slit-lamp system a proparacaine hydrochloride drop will be instilled in the eye to be treated. A Goldmann goniolens or a Latina SLT or any other goniolens will be placed on the eye to be treated with methyl cellulose 1%. The helium-neon aiming beam is focused onto the pigmented trabecular meshwork. SLT will be performed with approximately 50 applications, a 400um spot size with energies varying from 0.8-1.2 mjoules.
Experimental: Argon laser trabeculoplasty (ALT)	Procedure: ALT; All eyes will be treated using Ophthalas 532 Eyelite Laser Photocoagulator (Alcon Surgical, Dallas-Fort Worth, Texas, USA. On the day of treatment, IOP will be measured, then on the day of treatment, IOP will be measured, then one drop of Apraclonidine 1% or Brimonidine 0.2% and pilocarpine 1% will be instilled. Before the patient is seated at the laser slit-lamp system a proparacaine hydrochloride drop will be instilled in the eye to be treated. A Goldmann goniolens will be placed on the eye to be treated with methyl cellulose 1%. The aiming beam is focused onto the anterior portion of the pigmented trabecular meshwork. ALT will be performed to the superior or inferior 180 degrees with ~ 50 applications, a 50um spot size with energies varying from 400-700 mW with 0.1 second duration.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
IOP (Intraocular Pressure)	The main primary outcome variable will be the intraocular pressures (IOP) at 1 hour, 6 weeks, 3, 6 & 12 months post-operatively	1 hour, 6 weeks, 3, 6 &12 months

Collaborators and Investigators

• Sponsor: University of Calgary
• Collaborators: Canadian Glaucoma Clinical Research Council
• Investigators: Principal Investigator: Andrew C Crichton, University of Calgary

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.

Study record dates

Study Major Dates

• Study Start: September 1, 2006
• Primary Completion (Actual): September 1, 2009
• Study Completion (Actual): October 1, 2009

Study Registration Dates

• First Submitted: May 17, 2010
• First Submitted That Met QC Criteria: May 18, 2010
• First Posted (Estimate): May 19, 2010

Study Record Updates

• Last Update Posted (Estimate): May 24, 2010
• Last Update Submitted That Met QC Criteria: May 21, 2010
• Last Verified: May 1, 2010

More Information

Terms related to this study

• Keywords: Ocular Hypertension; Glaucoma; Pseudoexfoliation; SLT; Selective Laser Trabeculoplasy (SLT); Argon Laser Trabeculoplasty (ALT)
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Eye Diseases; Uveal Diseases; Iris Diseases; Glaucoma; Ocular Hypertension; Hypertension; Exfoliation Syndrome
• Other Study ID Numbers: SLT1