Optimal Treatment Protocol for Selective Laser Trabeculoplasty

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

Detailed Description
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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.

Official Title
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Optimal Treatment Protocol for Selective Laser Trabeculoplasty

Conditions
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Glaucoma, Open-Angle, Pseudoexfoliation Glaucoma, Ocular Hypertension

Intervention / Treatment
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* Procedure: SLT


Participation Criteria
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Eligibility Criteria
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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.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 180/low<br>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<br>* 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).<br>|
| Experimental: 180/high<br>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<br>* 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).<br>|
| Experimental: 360/low<br>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<br>* 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).<br>|
| Experimental: 360/high<br>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<br>* 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).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in intraocular pressure (IOP) | 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. | Before SLT and thereafter regularly for 3 years | 
| Achievement of 20% reduction in IOP | 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. | For 3 years | 
| Survival (no additional intervention) | 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). | For 3 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Survival (SLT allowed) | See Outcome 3. Kaplan-Meier survival analysis is performed the same way, but additional SLT-treatment will not be judged as failure. | For 3 years | 
| Pain perioperatively: on a scale | The patient will grade perioperative pain on an arbitrary scale between 0 (no pain) and 4 (maximum pain) on a written protocol. | Immediately after treatment | 
| Pain postoperatively: on a scale | 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. | During the first month | 
| Light sensitivity postoperatively | 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. | During the first month | 
| Impairment of vision postoperatively | 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. | During the first month | 
| Redness postoperatively | 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. | During the first month | 
| Flare (inflammation measurement of the anterior chamber) | 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. | Pre-operatively and then one day, one week and one month post-operatively. | 
| Adverse events | The type and frequency of adverse events will be recorded and analyzed in each of the study arms. | 3 years (although adverse events, if any, are anticipated to emerge in the first post-operative days or weeks). | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Selective Laser Trabeculoplasty