Optimal Treatment Protocol for Selective Laser Trabeculoplasty (OSLT)

• ClinicalTrials.gov Identifier: NCT03798223
• Recruitment Status: Enrolling by invitation
• First Posted: January 9, 2019
• Last Update Posted: January 12, 2022
• Sponsor: Vastra Gotaland Region
• Collaborator: Göteborg University
• Information provided by (Responsible Party): Vastra Gotaland Region

Study Description

Brief Summary:

A randomized controlled trial to evaluate which treatment protocol in selective laser trabeculoplasty that is most optimal in terms of efficacy and safety.

Condition or disease	Intervention/treatment	Phase
Glaucoma, Open-Angle; Pseudoexfoliation Glaucoma; Ocular Hypertension	Procedure: SLT	Not Applicable

Detailed Description:

A randomized controlled trial in which individuals scheduled for SLT are randomized to one of four treatment protocols, which represent the most common variants of the treatment in clinical use.

Treatment is performed either at 360 degrees or 180 degrees and with a laser energy level either 0,1 millijoules (mJ) below the microbubble formation limit ("low" energy) or at a level that gives microbubbles at 50-75% of laser effects ("high" energy). This gives four treatment arms: 180/low, 180/high, 360/low and 360/high. Group allocation is masked for the patient and is coded in the records.

The results for short and long term treatment effects are compared between the groups, as well as the complication rate and postoperative discomfort.

Study Design

• Study Type: Interventional (Clinical Trial)
• Estimated Enrollment: 400 participants
• Allocation: Randomized
• Intervention Model: Parallel Assignment
• Masking: Double (Participant, Outcomes Assessor)
• Masking Description: The treatment protocol is masked for the patient and for the nurses conducting measures of intraocular pressure during follow-up.
• Primary Purpose: Treatment
• Official Title: Optimal Treatment Protocol for Selective Laser Trabeculoplasty
• Actual Study Start Date: January 10, 2019
• Estimated Primary Completion Date: May 31, 2025
• Estimated Study Completion Date: May 31, 2025

Arms and Interventions

Arm	Intervention/treatment
Experimental: 180/low; SLT treatment in the lower half of the trabecular meshwork (180 degrees) consisting of 50+/-5 adjacent laser effects. The energy is adjusted 0,1 mJ below the threshold of formation of micro bubbles.	Procedure: SLT; A drop of Pilocarpine 4% is administered to the eye 20 minutes before SLT. Immediately before SLT a drop of Tetracaine hydrochloride 1% is administered. Selective laser trabeculoplasty is conducted through a Latina lens, in a fashion determined by randomization to a study arm (see description).
Experimental: 180/high; SLT treatment in the lower half of the trabecular meshwork (180 degrees) consisting of 50+/-5 adjacent laser effects. The energy is adjusted to achieve the formation of micro bubbles at 50-75% of laser effects.	Procedure: SLT; A drop of Pilocarpine 4% is administered to the eye 20 minutes before SLT. Immediately before SLT a drop of Tetracaine hydrochloride 1% is administered. Selective laser trabeculoplasty is conducted through a Latina lens, in a fashion determined by randomization to a study arm (see description).
Experimental: 360/low; SLT treatment in the full circumference of the trabecular meshwork (360 degrees) consisting of 100+/-10 adjacent laser effects. The energy is adjusted 0,1 mJ below the threshold of formation of micro bubbles.	Procedure: SLT; A drop of Pilocarpine 4% is administered to the eye 20 minutes before SLT. Immediately before SLT a drop of Tetracaine hydrochloride 1% is administered. Selective laser trabeculoplasty is conducted through a Latina lens, in a fashion determined by randomization to a study arm (see description).
Experimental: 360/high; SLT treatment in the full circumference of the trabecular meshwork (360 degrees) consisting of 100+/-10 adjacent laser effects. The energy is adjusted to achieve the formation of micro bubbles at 50-75% of laser effects.	Procedure: SLT; A drop of Pilocarpine 4% is administered to the eye 20 minutes before SLT. Immediately before SLT a drop of Tetracaine hydrochloride 1% is administered. Selective laser trabeculoplasty is conducted through a Latina lens, in a fashion determined by randomization to a study arm (see description).

Outcome Measures

Primary Outcome Measures :

1. Change in intraocular pressure (IOP) [ Time Frame: Before SLT and thereafter regularly for 3 years ]

   The IOP is measured with a Goldmann Applanation Tonometer (GAT) three times before SLT and then at regular intervals after the procedure. The reduction is registered and analyzed in absolute (mmHg) and relative (percent of the IOP before SLT) measures.

   Measurement of IOP is planned 1, 3, 6 and 12 months post SLT, and thereafter every six months for 3 years after SLT. The study is conducted in a regular clinical setting and the above mentioned times might be delayed. If target pressure is not achieved, measurements will be planned at shorter intervals, according to a specified algorithm, due to safety reasons.

2. Achievement of 20% reduction in IOP [ Time Frame: For 3 years ]
   See Outcome 1. Analysis of differences between the study arms will also be conducted measuring the proportion of eyes achieving 20% reduction in IOP or more at different time points in each group.
3. Survival (no additional intervention) [ Time Frame: For 3 years ]
   Kaplan-Meier survival analysis will be conducted, measuring the proportion of eyes that stay in the study groups but do not receive any further IOP-lowering intervention (medical, surgical or laser).

Secondary Outcome Measures :

1. Survival (SLT allowed) [ Time Frame: For 3 years ]
   See Outcome 3. Kaplan-Meier survival analysis is performed the same way, but additional SLT-treatment will not be judged as failure.
2. Pain perioperatively: on a scale [ Time Frame: Immediately after treatment ]
   The patient will grade perioperative pain on an arbitrary scale between 0 (no pain) and 4 (maximum pain) on a written protocol.
3. Pain postoperatively: on a scale [ Time Frame: During the first month ]
   The patient will grade post-operative pain on an arbitrary scale between 0 (no pain) and 4 (maximum pain) on a written protocol, also stating the duration of pain.
4. Light sensitivity postoperatively [ Time Frame: During the first month ]
   The patient will grade post-operative sensitivity to light on an arbitrary scale between 0 (no difference) and 4 (very intense sensitivity to light) on a written protocol, also stating the duration of light sensitivity.
5. Impairment of vision postoperatively [ Time Frame: During the first month ]
   The patient will grade post-operative impairment of vision on an arbitrary scale between 0 (no difference) and 4 (cannot see ones own hand) on a written protocol, also stating the duration of vision impairment.
6. Redness postoperatively [ Time Frame: During the first month ]
   The patient will grade post-operative redness of the eye on an arbitrary scale between 0 (no difference) and 4 (very intense redness) on a written protocol, also stating the duration of redness.
7. Flare (inflammation measurement of the anterior chamber) [ Time Frame: Pre-operatively and then one day, one week and one month post-operatively. ]
   15 participants from each treatment arm (60 in total, randomized in a separate block after informed consent) will undergo measurement with a Laser Flare Meter.
8. Adverse events [ Time Frame: 3 years (although adverse events, if any, are anticipated to emerge in the first post-operative days or weeks). ]
   The type and frequency of adverse events will be recorded and analyzed in each of the study arms.

Eligibility Criteria

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

Criteria

Inclusion Criteria:

• diagnosis primary open-angle glaucoma, pseudo-exfoliative glaucoma or ocular hypertension.
• intra-ocular pressure (IOP) at least 18 mmHg treatment day.
• treatment is performed by an experienced laser surgeon.
• SLT treatment and follow-up are expected to be possible to perform in an adequate way, considering anatomical factors, age and the general health of the patient.

Exclusion Criteria:

• change of IOP-lowering medication during the last three months.
• planned change of intra-ocular-pressure-lowering medication.
• previous glaucoma surgery (other than SLT and ALT)
• previous intra-ocular surgery during the last three months.
• previous intra-ocular inflammatory disease during the last year.
• planned intra-ocular surgery.
• hyper-pigmented anterior chamber angle.

Contacts and Locations

Locations

Sweden

Ogonkliniken, Sodra Alvsborgs Sjukhus

Boras, Vastra Gotaland, Sweden, 50182

Ogonkliniken, Sahlgrenska Universitetssjukhuset

Molndal, Vastra Gotaland, Sweden, 43130

Ogonkliniken, Skaraborgs Sjukhus

Skovde, Vastra Gotaland, Sweden, 54142

Ogonkliniken NU-sjukvarden

Uddevalla, Vastra Gotaland, Sweden, 45153

Sponsors and Collaborators

Vastra Gotaland Region

Göteborg University

Investigators

• Study Chair: Marcelo Ayala, MD, PhD; Vastra Gotaland Region
• Principal Investigator: Tobias Dahlgren, MD; Vastra Gotaland Region

More Information

• Responsible Party: Vastra Gotaland Region
• ClinicalTrials.gov Identifier: NCT03798223
• Other Study ID Numbers: Optimal SLT; 254861 ( Other Identifier: FoU i VGR ID nr )
• First Posted: January 9, 2019
• Last Update Posted: January 12, 2022
• Last Verified: January 2022

Individual Participant Data (IPD) Sharing Statement:

• Plan to Share IPD: No

• Studies a U.S. FDA-regulated Drug Product: No
• Studies a U.S. FDA-regulated Device Product: No
• Product Manufactured in and Exported from the U.S.: No

Keywords provided by Vastra Gotaland Region:

Selective Laser Trabeculoplasty

Additional relevant MeSH terms:

Glaucoma; Ocular Hypertension; Glaucoma, Open-Angle; Exfoliation Syndrome; Eye Diseases; Iris Diseases; Uveal Diseases