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Completed

NCT Number: NCT03187418

Treatment Outcomes of MicroPulse Trans-scleral Cyclophotocoagulation in Uncontrolled Glaucoma

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.

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Key information

Conditions

Glaucoma Eye Diseases Glaucoma Eye Glaucoma Secondary Glaucoma and Ocular Hypertension Glaucoma, Angle-Closure Glaucoma, Neovascular Glaucoma, Open-Angle Glaucoma, Uncompensated Ocular Hypertension

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Centre Hospitalier de l'Université de Montréal (CHUM)

Montreal, Quebec, H2X 3E4, Canada

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

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

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.
  • mild glaucoma: IOP > 18 mmHg
  • moderate glaucoma: IOP > 15 mmHg
  • 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.

Treatment and study plan

MicroPulse® P3 Glaucoma Device (MP3)

Device

Laser settings will be programmed as follows: power-2000mW-2500mW (average 2000mW) of 810nm infrared diode laser set on micropulse delivery mode; micropulse "on" time-0.5ms; micropulse "off" time-1.1ms; and duty cycle (proportion of each cycle during which the laser is on)-31.33 %.

The laser probe will be applied in a continuous sliding or painting motion from 9:30 to 2:30 and from 3:30 to 8:30. The probe will be applied perpendicular to the limbus with the edge directly on the limbus at all times (fiberoptic tip at 3 mm posterior to the limbus).

The laser will be delivered over 360° for 160-320s. Treatment duration will be adjusted based on iris color and glaucoma severity (mild glaucoma: 160s, moderate glaucoma: 240s, advanced glaucoma: 240-320s).

Other names: CYCLO G6 Glaucoma Laser System (Iridex, Mountain View, CA)

Primary outcomes

  1. Intraocular Pressure (IOP)

    Time frame: 18 months

    In millimeters of mercury (mmHg), measured with the Goldmann applanation tonometer

Secondary outcomes

  1. Intraocular Pressure (IOP)

    Time frame: 1 week, 1 month, 3 months, 6 months, 12 months

    In millimeters of mercury (mmHg), measured with the Goldmann applanation tonometer

  2. Number of Participants With Repeat Treatments

    Time frame: 18 months

    Number of participants needing a repeat laser treatment during the study

  3. Number of Intraocular Pressure Lowering Medications

    Time frame: 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

  4. Corrected Distance Visual Acuity (CDVA)

    Time frame: 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

  5. Cup-to-disc Ratio (CDR)

    Time frame: 18 months

    Progression of CDR compared to baseline, assessed by an ophthalmologist on dilated fundus examination

  6. Visual Field Index (VFI)

    Time frame: 18 months

    Determined by Humphrey automated perimetry Sita 24-2 visual field testing

  7. Mean Deviation (MD)

    Time frame: 18 months

    Determined by Humphrey automated perimetry Sita 24-2 visual field testing

  8. Pattern Standard Deviation (PSD)

    Time frame: 18 months

    Determined by Humphrey automated perimetry Sita 24-2 visual field testing

  9. Average Retinal Nerve Fiber Layer (RNFL) Thickness

    Time frame: 18 months

    In micrometer, determined by optical coherence tomography (OCT)

  10. Average Ganglion Cell Layer (GCL) Thickness

    Time frame: 18 months

    In micrometer, determined by optical coherence tomography (OCT)

  11. Cup-to-disc Ratio (CDR) Assessed by Optical Coherence Tomography (OCT)

    Time frame: 18 months

    Progression of vertical CDR compared to baseline, assessed by optical coherence tomography (OCT) parameters

  12. Pain Level During Laser Treatment

    Time frame: 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)

Sponsors and collaborators

Lead sponsor

Centre hospitalier de l'Université de Montréal (CHUM)

Other

Registry information

Official study title

Treatment Outcomes of MicroPulse Trans-scleral Cyclophotocoagulation (mTSCPC) in Uncontrolled Glaucoma at the University of Montreal Hospital Center (CHUM)

Important dates

Study start
2017
Primary completion
2020
Study completion
2020
First posted
Jun 15, 2017
Registry last updated
Oct 8, 2021

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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