Treatment Outcomes of MicroPulse Trans-scleral Cyclophotocoagulation in Uncontrolled Glaucoma

Not Applicable

Completed

Conditions: Glaucoma, Neovascular
Glaucoma, Uncompensated
Glaucoma Secondary
Glaucoma, Open-Angle
Glaucoma Eye
Glaucoma
Glaucoma and Ocular Hypertension

Interventions: Device: MicroPulse® P3 Glaucoma Device (MP3)

Registration Number: NCT03187418

Lead Sponsor: Centre hospitalier de l'Université de Montréal (CHUM)

Brief Summary: The goal of this study is to evaluate the efficacy and safety of the novel form of trans-scleral cyclophotocoagulation using micropulse diode laser and trans-pars plana treatment (Micropulse TSCPC, mTSCPC MP3, IRIDEX CYCLO G6™ Glaucoma Laser System, CA, USA) in adults for the treatment of uncontrolled glaucoma.

Detailed Description: Cyclophotocoagulation (CPC) is a type of cycloablation using laser to treat glaucoma. It involves ciliary body destruction by targeting the ciliary epithelium and stroma, resulting in a reduction in aqueous secretion and hence intraocular pressure. This strategy is effective for all forms of glaucoma.

Traditional trans-scleral cyclophotocoagulation (TSCPC) achieve its cyclodestructive action by using continuous diode laser to target the melanin in the pigmented ciliary body epithelium. However, the continuous mode has been shown to cause significant collateral tissue damage to adjacent non-pigmented structures including the ciliary stroma and ciliary muscle. Traditional TSCPC may therefore be associated with serious complications including uveitis, visual deterioration, chronic hypotony, and others.

More recently, a micropulse delivery mode of diode laser (Micropulse TSCPC, mTSCPC) has been used to treat glaucoma by ablating the ciliary processes and reduce aqueous humor production with more selective targeting and less collateral damage. In contrast to conventional laser delivery where a continuous flow of high intensity energy is delivered, micropulse laser application delivers a series of repetitive short pulses of energy with rest periods in between pulses. Only a few studies have described the outcomes of this novel glaucoma therapy, showing mTSCPC to have comparable efficacy with fewer side effects when compared with traditional continuous wave mode diode laser delivery.This improved side effect profile has the potential to make mTSCPC an earlier therapeutic option instead of reserving it exclusively for end-stage refractory eyes.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 52

Inclusion Criteria

Patients of either sex and any race aged 18 years old and above.
Followed by a glaucoma subspecialist at University of Montreal Hospital Center.
Intraocular pressure (IOP) above target and unresponsive to maximal tolerated medical therapy with or without previous surgical intervention.
1. mild glaucoma: IOP > 18 mmHg
2. moderate glaucoma: IOP > 15 mmHg
3. advanced glaucoma: IOP > 12 mmHg
Considered poor candidates for additional filtering surgery or implantation of glaucoma drainage devices.

Exclusion Criteria

Patients unable to give informed consent.
Patients with significant scleral thinning, defined as thinning of more than one clock hour noticed on scleral transillumination.
Ocular infection or inflammation in the study eye in the 2 months prior to enrolment.
Intraocular surgery in the study eye in the 2 months prior to enrolment.

Study & Design

Study Type: INTERVENTIONAL

Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Micropulse trans-scleral CPC	MicroPulse® P3 Glaucoma Device (MP3)	A treatment session of micropulse trans-scleral cyclophotocoagulation in the affected eye, using the MicroPulse® P3 Glaucoma Device (MP3) powered by the CYCLO G6™ Glaucoma Laser System (Iridex, Mountain View, CA, USA).

Primary Outcome Measures

Name	Time	Method
Intraocular Pressure (IOP)	18 months	In millimeters of mercury (mmHg), measured with the Goldmann applanation tonometer

Secondary Outcome Measures

Name	Time	Method
Mean Deviation (MD)	18 months	Determined by Humphrey automated perimetry Sita 24-2 visual field testing
Number of Participants With Repeat Treatments	18 months	Number of participants needing a repeat laser treatment during the study
Intraocular Pressure (IOP)	1 week, 1 month, 3 months, 6 months, 12 months	In millimeters of mercury (mmHg), measured with the Goldmann applanation tonometer
Pain Level During Laser Treatment	1 day	Using a verbal analog scale for pain level (none = no subjective feeling of pain, mild = pain easily tolerable, moderate = pain tolerable with difficulty, severe = pain intolerable)
Number of Intraocular Pressure Lowering Medications	1 week, 1 month, 3 months, 6 months, 12 months, 18 months	Number of drops and oral medications used by the patient compared to baseline
Corrected Distance Visual Acuity (CDVA)	1 week, 1 month, 3 months, 6 months, 12 months, 18 months	Number of lines reduction or improvement from baseline on Snellen acuity chart at 6 meters
Cup-to-disc Ratio (CDR)	18 months	Progression of CDR compared to baseline, assessed by an ophthalmologist on dilated fundus examination
Visual Field Index (VFI)	18 months	Determined by Humphrey automated perimetry Sita 24-2 visual field testing
Pattern Standard Deviation (PSD)	18 months	Determined by Humphrey automated perimetry Sita 24-2 visual field testing
Cup-to-disc Ratio (CDR) Assessed by Optical Coherence Tomography (OCT)	18 months	Progression of vertical CDR compared to baseline, assessed by optical coherence tomography (OCT) parameters
Average Retinal Nerve Fiber Layer (RNFL) Thickness	18 months	In micrometer, determined by optical coherence tomography (OCT)
Average Ganglion Cell Layer (GCL) Thickness	18 months	In micrometer, determined by optical coherence tomography (OCT)