Uddevalla Skövde Transscleral Micropulse Study

Official 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

Overview

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.

Detailed description

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.

Interventions

• Procedure Topical lidocaine
  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.
• Procedure MP-TLT
  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 outcome measures

• Relative IOP change (percent) [Time frame: 6 months]
• Relative IOP change (percent) for POAG and PXFG eyes separately [Time frame: 6 months]
• Perioperative pain on a visual analogue scale (VAS) [Time frame: Immediately after surgery]

Secondary outcome measures (10)

• Success proportion after 12 months [Time frame: 12 months]
• Survival [Time frame: 12 months]
• Relative change (percent) of the IOP 1 week, 1 month, 3 months and 12 months after MP-TLT. [Time frame: 12 months]
• Postoperative pain on a VAS 1 hour, 5 hours, and 24 hours postoperatively [Time frame: 1 hour, 5 hours, and 24 hours postoperatively]
• Patient reported discomfort on an arbitrary scale [Time frame: 1 month]
• Change in central retinal thickness (CRT) postoperatively [Time frame: 3 months]
• Change in central corneal thickness (CCT) postoperatively [Time frame: 1 month]
• Change of flare in the anterior chamber postoperatively [Time frame: 1 month]
• Change in visual field index (VFI) during follow-up [Time frame: 12 months]
• Adverse events [Time frame: 12 months]

Eligibility criteria

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.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Observational model

Cohort

Study locations

Sweden · 2 centers

• Department of Ophthalmology, Skaraborg Hospital — Skövde
• Department of Ophthalmology, NU Hospital Group — Uddevalla

Publications

• Grippo TM, de Crom RMPC, Giovingo M, Toteberg-Harms M, Francis BA, Jerkins B, Brubaker JW, Radcliffe N, An J, Noecker R. Evidence-Based Consensus Guidelines Series for MicroPulse Transscleral Laser Therapy: Dosimetry and Patient Selection. Clin Ophthalmol. 2022 Jun 7;16:1837-1846. doi: 10.2147/OPTH.S365647. eCollection 2022. PMID 35698599

Identifiers

NCT: NCT05557721 · USTMS · 278487

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗