Timing of Glaucoma Drainage Device With Boston Keratoprosthesis

Summary

Boston keratoprosthesis (KPro) is a piece of specialized plastic that replace sick cornea (transparent structure at the front of the eye) in patients who have failed or those who are expected to have poor results with traditional corneal transplantation. While the Kpro can offer dramatic improvement in vision, it is also associated with several complications. Glaucoma (optic nerve damage due to high pressure inside the eye) is one of the most common complications after KPro surgery and can potentially cause irreversible vision loss. The implantation of a glaucoma drainage device (GDD), a tiny tube that drains the liquid inside the eye by bypassing the natural drainage system, is an effective option to lower the eye pressure in patients with KPro. Given the frequency and potentially devastating effects of glaucoma among KPro patients, some surgeons recommend to put in a GDD as a preventative measure. However, there is no consensus on when is the best timing to perform such surgery in relation to the Boston Kpro surgery.

Hypothesis:

For patients undergoing the Boston KPro surgery, implanting a GDD simultaneously, at the time of surgery, is more efficacious than at 6 months later, in the prevention of the progression of glaucoma and in maintaining better visual functions.

Methods:

The investigators aim to recruit 40 patients over 4 years. Recruited patients will be randomly assigned to 2 groups: 1) simultaneous GDD implantation at the Boston KPro surgery, and 2) GDD implantation 6 months after the Boston KPro surgery.

Once recruited, patients will be followed before the KPro surgery, postoperative day 1, week 1, month 1, 3, 6 and 12. Standard ophthalmological exam will be performed at each visit. Additional non-invasive glaucoma tests and evaluation (visual fields and optic nerve photo) will be performed on day 1, month 1, 3, 6 and 12.

For patients assigned to group 2, a GDD will be implanted 6 months after the KPro surgery. They will have additional follow-ups on post-GDD surgery day 1, week 1 and month 1.

Results of visual acuity, visual fields, optic nerve evaluation and complications will be compared between the two groups to determine the better timing of GDD implantation.

Conditions

• Corneal Transplantation
• Glaucoma

Interventions

PROCEDURE

Boston keratoprosthesis type 1

The Boston KPro, purchased from Massachusetts Eye and Ear infirmary (Boston, MA), is implanted using the usual standard technique.

PROCEDURE

Glaucoma drainage device

The GDD that will be used is the Ahmed implant (New World Medical, Rancho Cucamonga, CA). The Ahmed implant will be implanted using the standard technique either at the time of KPro surgery in group 1, or 6 months following KPro in group 2.

Sponsors & Collaborators

• Centre hospitalier de l'Université de Montréal (CHUM)

  lead OTHER

Principal Investigators

• Mona Harissi-Dagher, MD, FRCSC · Department of Ophthalmology, Centre Hospitalier de l'Université de Montréal

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2014-05-26

Primary Completion

2025-12-31

Completion

2025-12-31

Countries

• Canada

Study Locations