The Role of Transscleral Cyclophotocoagulation in Patients Undergoing a Boston Keratoprosthesis

NCT04232982 | Recruiting

• 1 other identifier: CE19.253
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief Summary

The Boston keratoprosthesis (KPro) is a special plastic device that is used to replace a sick cornea (transparent part of the eye, in front of the iris) in order to restore vision in patients who have failed traditional corneal transplants or have a very poor prognosis of success. Glaucoma is a chronic disease which causes optic nerve damage secondary to high pressure inside the eye and could lead to vision loss in the long term. Glaucoma is highly prevalent in patients who require a KPro and even more after their procedure. In order to decrease the intra-ocular pressure, surgeons can use multiple eyedrops. Unfortunately, following the KPro surgery, eyedrops lose their efficiency because they are less absorbed by the eye. The transscleral cyclophotocoagulation (TS-CPC) is a laser treatment used in advanced refractory glaucoma. This laser helps decrease the intra-ocular pressure and have a better control of the disease. There are different methods of laser transmission, including the continuous transmission (G-Probe) and the micro-pulsation method (Micopulse). Given the high prevalence of glaucoma in patients receiving a KPro, the investigators are studying the effect of giving the TS-CPC treatment prophylactically to patients before their Boston keratoprosthesis. Our hypothesis is that prophylactic TS-CPC will decrease glaucoma progression as well as the risks of developing glaucoma following the Boston keratoprosthesis . METHOD The investigators aim to recruit twenty (20) patients who are scheduled to receive Boston KPro. Participants will be randomized into two groups: 1) Groupe 1 will receive a prophylactic treatment of transscleral cyclophotocoagulation a G-Probe. 2) Groupe 2 will receive a prophylactic treatment of transscleral cyclophotocoagulation with a micropulse transmission (MicroPulse). The patients will receive their laser treatment by a glaucoma specialist 4 to 8 weeks before their KPro surgery. One week following their laser treatment, the participants will be examined by their glaucoma specialist. Following their KPro surgery, patients will have a follow-up at day-1, weeks 1 and 2, months 1 and 3, then every 4 to 6 months for 5 years. Additional non-invasive glaucoma tests will be performed twice during the first 3 months following the surgery and will be repeated every 4-6 months. Visual acuity results, the visual field tests and rates of post-operative complications will be compared between the different groups.

Conditions

Glaucoma; Eye Diseases; Cornea Disease

Keywords

Boston keratoprosthesis; Transscleral cyclophotocoagulation; Micropulse transscleral cyclophotocoagulation; G-Probe Transscleral cyclophotocoagulation

Outcome Measures

Primary Outcomes (1)

• Cup-to-disc ratio

  Rate of progression of the optic nerve cup-to-disc ratio

  5 years

Secondary Outcomes (4)

• No light perception

  5 years

• Need of additional glaucoma intervention

  5 years

• Goldman visual field loss of 30% or more.

  5 years

• Retinal Nerve Fiber Layer thinning

  5 years

Other Outcomes (2)

• Complications related to transscleral cyclophotocoagulation treatment

  5 years

• Complications related to the Boston keratoprosthesis

  5 years

Study Arms (3)

MicroPulse Treatment

EXPERIMENTAL

Prophylactic transscleral cyclophotocoagulation treatment, delivered by micropulse waves will be given 4-8 weeks before the Boston keratoprosthesis surgery.

Procedure: Transscleral cyclphophotocoagulation using the Micropulse system ( IRIDEX IQ810 Laser systems, Mountain View, CA).

G-Probe Treatment

EXPERIMENTAL

Prophylactic transscleral cyclophotocoagulation treatment, delivered with a diode laser using the G-Probe device, will be given 4-8 weeks before the Boston keratoprosthesis surgery.

Procedure: G-Probe transscleral cyclphophotocoagulation (Iris Medical Instruments, Montain View, CA)

Historical Cohort

NO INTERVENTION

An historical cohort composed of patients who received a Boston keratoprosthesis between january 2017 and january 2019 will be included. Only patients who did not receive any glaucoma treatment 3 months before their surgery will be included. A total of 10 patients will be selected with the goal of matching the preoperative characteristics of the interventional patients. This group will serve as the control group in our study. Retrospective chart review will be performed for this branch.

Interventions

G-Probe transscleral cyclphophotocoagulation (Iris Medical Instruments, Montain View, CA) PROCEDURE

Treatment will be applied over the limbal area to treat the ciliary body. Sixteen (16) shots in total, which is four (4) shorts per quadrants, will be transmitted with a power from 1750 to 2000mV (titrating according to an audible "pop") for a length of 2,0 secondes per shots. Treatment will be delivered around a 360° surface and avoiding the 3 and 9 o'clock areas.

G-Probe Treatment

Transscleral cyclphophotocoagulation using the Micropulse system ( IRIDEX IQ810 Laser systems, Mountain View, CA). PROCEDURE

Treatment will be applied over the limbal area to treat the ciliary body. The treatment will be delivered with an energy of 2000mW, a cycle of 31,33% and an on/off time of 0,5ms and 1,1ms. It will be delivered around a 360° surface with avoidance of the 3 and 9 o'clock areas. The treatment will be delivered during 80 secondes in each hemisphere and will be repeated twice, for a total of 320 secondes.

Also known as: MP-TSCPC

MicroPulse Treatment

Eligibility Criteria

• Age: 18 Years - 80 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Adults patients
• Able to give an informed consent
• Capable of being followed during the study
• Candidate for the Boston keratoprosthesis type I

You may not qualify if:

• Patients younger than 18 years old or older than 80 years old
• Unable to give an informed consent
• Participating to another interventional glaucoma study
• Patients who received a glaucoma surgery or procedure (glaucoma drainage device or TS-CPC treatment) 3 months before their initial visit.
• Unable to wear a therapeutic contact lens secondary to eyelid malformation
• Severe Ocular surface Disease with keratinization
• Intra-ocular tumor
• Terminal Glaucoma
• Phthisis bulbi
• Ocular albinism

Sponsors & Collaborators

• Centre hospitalier de l'Université de Montréal (CHUM): lead
• Fonds de recherche en ophtalmologie de l'Université de Montréal: collaborator

Study Sites (1)

Centre Hospitalier de l'Université de Montréal (CHUM)

Montreal, Quebec, H2X 3E4, Canada

RECRUITING

Related Publications (6)

• Robert MC, Pomerleau V, Harissi-Dagher M. Complications associated with Boston keratoprosthesis type 1 and glaucoma drainage devices. Br J Ophthalmol. 2013 May;97(5):573-7. doi: 10.1136/bjophthalmol-2012-302770. Epub 2013 Feb 23.

  PMID: 23435225 BACKGROUND

• Vajaranant TS, Liu J, Wilensky J, Cortina MS, Aref AA. Innovative approaches to glaucoma management of Boston keratoprosthesis type 1. Curr Ophthalmol Rep. 2016 Sep;4(3):147-153. doi: 10.1007/s40135-016-0102-3. Epub 2016 Jul 26.

  PMID: 28529825 BACKGROUND

• Jabbour S, Harissi-Dagher M, Agoumi Y, Singh H, Robert MC. Cyclophotocoagulation in the Control of Glaucoma in Patients With the Boston Keratoprosthesis Type 1. Cornea. 2020 Feb;39(2):181-185. doi: 10.1097/ICO.0000000000002064.

  PMID: 31335536 BACKGROUND

• Rivier D, Paula JS, Kim E, Dohlman CH, Grosskreutz CL. Glaucoma and keratoprosthesis surgery: role of adjunctive cyclophotocoagulation. J Glaucoma. 2009 Apr-May;18(4):321-4. doi: 10.1097/IJG.0b013e3181815485.

  PMID: 19365199 BACKGROUND

• Patel S, Takusagawa H, Shen L, Dohlman C, Grosskreutz C. Long-term complications associated with glaucoma drainage devices and Boston keratoprosthesis. Am J Ophthalmol. 2012 Jul;154(1):207-8; author reply 208-9. doi: 10.1016/j.ajo.2012.02.033. No abstract available.

  PMID: 22709836 BACKGROUND

• Crnej A, Paschalis EI, Salvador-Culla B, Tauber A, Drnovsek-Olup B, Shen LQ, Dohlman CH. Glaucoma progression and role of glaucoma surgery in patients with Boston keratoprosthesis. Cornea. 2014 Apr;33(4):349-54. doi: 10.1097/ICO.0000000000000067.

  PMID: 24531120 BACKGROUND

MeSH Terms

Conditions

Glaucoma; Eye Diseases; Corneal Diseases

Condition Hierarchy (Ancestors)

Ocular Hypertension

Study Officials

• Marie-Claude Robert, MD, MSc

  Ophthalmology Department, Centre Hospitalier de l'Université de Montreal

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Marie-Catherine Thessier, MSc

CONTACT

514 890-8000; marie-catherine.tessier.chum@ssss.gouv.qc.ca

Soumaya Bouhout, MD

CONTACT

5142640436; soumaya.bouhout@umontreal.ca

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Masking Details: Patients will not be aware of which type of cyclophotocoagulation treatment they will be allocated.
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Prospective, randomized, single blinded study with two interventional arms and one historical cohort as controls.

Study Record Dates

• First Submitted: January 13, 2020
• First Posted: January 18, 2020
• Study Start: January 30, 2020
• Primary Completion (Estimated): December 1, 2034
• Study Completion (Estimated): December 1, 2036
• Last Updated: April 27, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share

Locations

CA (1)