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NCT Number: NCT05557721

Uddevalla Skövde Transscleral Micropulse Study

Micro pulse transscleral laser treatment (MP-TLT) is a relatively new method to reduce the intraocular pressure (IOP) in glaucoma. New recommendations regarding the treatment protocol has recently been developed and was published 2022.

The overall objective is to evaluate the efficacy and safety of the proposed treatment method in an independent study. In addition, the outcome of MP-TLT in patients with pseudoexfoliation glaucoma, which is relatively common in the Nordic countries, and primary open angle glaucoma will be studied separately.

The IOP change over the course of one year will be monitored, as well as success rate and survival. Further, patient-reported discomfort from the treatment and the occurrence of any adverse events or complications will be studied.

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Key information

Conditions

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

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Department of Ophthalmology, Skaraborg Hospital, Skövde, Västra Götaland County, Sweden

Loading trial locations.

About this study

Forty patients scheduled for MP-TLT by their ophthalmologist will be recruited. One eye per patient is included, based on randomization, even if both are treated. MP-TLT will be performed according to the current recommendations.

Baseline IOP will be calculated as the mean of three separate measurements taken on different days preoperatively. IOP will then be measured 1 week, 1 month, 3 months, 6 months and 12 months after MP-TLT.

The central corneal thickness (CCT), the central retinal thickness (CRT), anterior chamber flare and the visual field (HFA 24-2 faster) will also be measured preoperatively and during follow up.

In accordance with the World Glaucoma Association guidelines, no adjustment for multiple comparisons is planned in this study.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Diagnosis of primary open angle glaucoma (POAG) or pseudo exfoliative glaucoma (PXFG)
  • Age ≥ 18 years
  • The patient is expected to be able to adequately undergo and cooperate in the treatment and follow-up as described in the study protocol.
  • The patient is judged to have good compliance with already prescribed pharmacological glaucoma treatment.

Exclusion criteria

  • Allergy or hypersensitivity to tetracaine or lidocaine
  • Prior transscleral laser or cryo treatment.
  • Prior eye surgery (including intravitreal injection) or pressure-lowering laser treatment (SLT/ALT/MDLT) during the last 2 months.
  • Planned or expected eye surgery (eg., cataract surgery or intravitreal injection) in the coming year.
  • History of macular edema.
  • History of corneal edema.
  • History of uveitis during the past year.
  • Existing thinning in the sclera of a greater extent than 30 degrees (one "clock-hour") of the circumference.

Treatment and study plan

Topical lidocaine

Procedure

Patients will receive topical anesthesia with tetracaine hydrochloride 1% three times, 5 minutes apart. Then, lidocaine gel 2% will be applied on the surface of the eye and refilled as needed for 10 minutes, as well as manipulated for a good coverage.

MP-TLT

Procedure

Micro pulse transscleral laser treatment will be performed with the Iridex CycloG6 laser with the revised P3 probe, according to the recent consensus recommendations.

In brief, this includes MP-TLT with 2500 mW, 31.3% duty cycle, four 20 second sweeps per hemisphere, avoiding the 3 and 9 o'clock meridians and sectors with scleral thinning.

Primary outcomes

  1. Relative IOP change (percent)

    Time frame: 6 months

    Relative IOP (intraocular pressure) change (percentage relative to baseline) for the entire study population. "Last observation carried forward" will be used in cases with treatment escalation or reduction during follow up. Patients with peroral glaucoma treatment at baseline are not included in this analysis.

  2. Relative IOP change (percent) for POAG and PXFG eyes separately

    Time frame: 6 months

    Relative IOP change (percentage relative to baseline) for the eyes with a diagnosis of primary open angle glaucoma, or pseudo exfoliative glaucoma, respectively. "Last observation carried forward" will be used in cases with treatment escalation or reduction during follow up. Patients with peroral glaucoma treatment at baseline are not included in this analysis.

  3. Perioperative pain on a visual analogue scale (VAS)

    Time frame: Immediately after surgery

    The patient will report pain during MP-TLT treatment on a VAS immediately after surgery.

    A 10 cm horizontal line without markings will be presented. One end of the line represents "no pain" and the other "worst imaginable pain". The patient marks the position on the scale that corresponds to the level of perceived pain. The number of millimeters from the "no pain" end is the result. Higher is worse.

    If there was a need for supplementary anesthesia, the grading applies to the experience before supplementation.

Secondary outcomes

  1. Success proportion after 12 months

    Time frame: 12 months

    Eyes will be graded with either "success" or "failure" after one year of follow up. Definition of success (all must be fulfilled):

    • Reduction of the IOP by at least 20% compared to baseline and/or reduction in pharmacological glaucoma treatment.
    • IOP ≥ 6 mmHg
    • No additional IOP reducing intervention performed after MP-TLT.

  2. Survival

    Time frame: 12 months

    Kaplan-Meier survival analysis regarding achievement and maintenance of "success" as defined above.

  3. Relative change (percent) of the IOP 1 week, 1 month, 3 months and 12 months after MP-TLT.

    Time frame: 12 months

    IOP change relative to baseline 1 week, 1 month, 3 month and 12 months after MP-TLT. "Last observation carried forward" will be used in cases with treatment escalation or reduction during follow up. Patients with peroral glaucoma treatment at baseline are not included in this analysis.

  4. Postoperative pain on a VAS 1 hour, 5 hours, and 24 hours postoperatively

    Time frame: 1 hour, 5 hours, and 24 hours postoperatively

    Postoperative pain on a VAS 1 hour, 5 hours, and 24 hours postoperatively. See above for further description.

  5. Patient reported discomfort on an arbitrary scale

    Time frame: 1 month

    The patients will report peri- and postoperative pain, postoperative light sensitivity, visual impairment and hyperemia. The scale goes between 0 (no sensation) and 4 (worst imaginable). The scale was developed for the OSLT trial (NCT03798223). Comparisons will be made with the results from that trial.

  6. Change in central retinal thickness (CRT) postoperatively

    Time frame: 3 months

    The thickness in the central retinal field will be measured with optical coherence tomography (OCT) at baseline and 1 week, 1 month and 3 months postoperatively. The relative change (percent) will be calculated for each time point.

  7. Change in central corneal thickness (CCT) postoperatively

    Time frame: 1 month

    The central corneal thickness (CCT) in the thinnest point will be measured with Pentacam at baseline and 1 week and 1 month postoperatively. The relative change (percent) will be calculated for each time point. Applies only to NU patients (one of the centers).

  8. Change of flare in the anterior chamber postoperatively

    Time frame: 1 month

    Flare in the anterior chamber will be measured with a Kowa laser flare meter at baseline and 1 week and 1 month postoperatively. The relative change (percent) will be calculated for each time point. Applies only to SkaS patients (one of the centers).

  9. Change in visual field index (VFI) during follow-up

    Time frame: 12 months

    The visual field will be assessed with a Humphrey field analyzer (HFA) 24-2 faster at baseline and then 1 and 12 months postoperatively. The change in VFI, expressed in percentage points, will be calculated for each time point.

  10. Adverse events

    Time frame: 12 months

    Suspected adverse events will be registered.

Sponsors and collaborators

Lead sponsor

Vastra Gotaland Region

Other Gov

Collaborators

  • Göteborg University

Registry information

Official study title

Uddevalla Skövde Transscleral Micropulse Study: Efficacy and Safety of Micro Pulse Transscleral Laser Treatment (MP-TLT) in Glaucoma Patients Performed in Topical Lidocaine Anaesthesia

Acronym: USTMS

Important dates

Study start
2023
Primary completion
2025
Study completion
2025
First posted
Sep 28, 2022
Registry last updated
Dec 3, 2024

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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