Clinical Trial: Corneal Endothelial Cell Loss After Trabeculectomy Versus Phakotrabeculectomy

Study Status: Not yet recruiting
Recruit Status: Not yet recruiting
Study Type: Interventional

Official Title: Corneal Endothelial Cell Loss After Trabeculectomy Versus Combined Trabeculectomy Phakoemulsification and IOL Implantation

Brief Summary:

Corneal endothelial cells health and pumping function is crucial to permit corneal optical clarity by keeping cornea in relatively dehydrated state. Corneal endothelial damage has been associated with most types of intraocular surgery. Trabeculectomy is the standard glaucoma surgical intervention in management of progressive glaucoma despite of medical therapy which can be performed in combination with Cataract surgery (Phacoemulsification and IOL implantation) in patients with cataract-impaired visual acuity.

In this study, the investigators will investigate and compare the corneal endothelial cells number and health status before and after trabeculectomy vs. combined surgery (at 1 month and 3 months post-op visits) using Specular microscopy which is a non-invasive technique to access the structure and function of the corneal endothelium by permitting visualization of the corneal endothelial mosaic to assess the effect of this surgical intervention on corneal endothelial cells health and number.


Detailed Summary:

Corneal endothelial cells health and pumping function is crucial to permit corneal optical clarity by keeping the cornea in a relatively dehydrated state.1 The corneal endothelium is a single layer of hexagonal cells with uniform size and shape in normal conditions. When endothelial cell density diminishes, the remaining cells increase in size to cover the empty spaces left by the dead cells, and therefore there is a change in the size (polymegathism) and morphology (pleomorphism) of the remaining cells. Trauma or other insults often cause endothelial cell death, which is irreparable because these cells lack division capacity.2,3,4 Corneal endothelial damage has been associated with most types of intraocular surgeries including glaucoma and cataract surgeries.5,6,7,8 Cataract and glaucoma are the most common causes of visual impairment worldwide.9,10

Phacoemulsification and Intraocular lens (IOL) insertion, the most commonly performed method of cataract extraction in the developed world, was first described in 1967.11 This technique allows rapid visual rehabilitation postoperatively and low induced astigmatism.11 The reported average loss of central corneal endothelial cells after phacoemulsification vary between 4% and 25%.8 Trabeculectomy, introduced by Cairns in 1968 12, is the most commonly performed incisional glaucoma procedure worldwide and has become the glaucoma filtering procedure of choice in glaucoma patients 5,13,14 with advanced glaucoma or poor tolerance or uncontrolled IOP despite of multiple topical or systemic medications with the goal of preserving vision and reducing the likelihood and rate of visual field loss and optic nerve changes in susceptible patients by reducing the intra ocular pressure (IOP) as the major risk factor.15,16 The use of anti-metabolites specifically Mitomycin C (MMC) as a supplement to trabeculectomy with more favorable effect on
Sponsor: Sunnybrook Health Sciences Centre

Current Primary Outcome: Endothelial cell count [ Time Frame: 3 months post surgery ]

Specular microscopy


Original Primary Outcome: Same as current

Current Secondary Outcome:

  • IOP [ Time Frame: 3 month visit ]
    Goldmann tonometry
  • Visual acuity [ Time Frame: 3 month visit ]
    Snellen Acuity
  • Endothelial cell morphology - qualitative [ Time Frame: 3 month visit ]
    Specular microscopy
  • Central corneal thickness [ Time Frame: 3 month visit ]
    Ultrasound pachymetry


Original Secondary Outcome: Same as current

Information By: Sunnybrook Health Sciences Centre

Dates:
Date Received: January 18, 2017
Date Started: April 2017
Date Completion: December 2017
Last Updated: April 4, 2017
Last Verified: April 2017