An interventional study of Corneal topography: OPD-Scan and Corneal topography: Pentacam in Glaucoma, Open-Angle, Glaucoma, Angle-Closure and Glaucoma Secondary, sponsored by Centre hospitalier de l'Université de Montréal (CHUM). Completed at 1 site in Canada. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2024-08-09.
Sponsored by Centre hospitalier de l'Université de Montréal (CHUM) · Not applicable, Interventional, and Treatment
The main goal of this study is to assess the severity of postoperative corneal astigmatism induced by implantation of the XEN Gel Stent compared to that induced by traditional filtering surgery (trabeculectomy and GDDs). Corneal astigmatism can be assessed using corneal topography, a non-invasive tool which provides an accurate estimate of corneal curvature in all meridians. To the best of our knowledge, no study has yet attempted to quantify the amount of astigmatism induced by the XEN Gel Stent.
Following glaucoma surgery, patients often experience decreased visual acuity (VA) which can partly be explained by induced changes to the optical properties of the cornea. Corneal astigmatism can be assessed using corneal topography, a non-invasive tool which provides an accurate estimate of corneal curvature in all meridians. Obtained keratometric measures (termed K values) can allow clinicians to quantify the amount of astigmatism before and after surgical intervention.
Multiple studies have been previously published to evaluate induced postoperative astigmatism after trabeculectomy. However, only two studies have characterized the impact of GDDs on keratometric values. To the best of our knowledge, no study has yet attempted to quantify the amount of astigmatism induced by the XEN Gel Stent.
Assessing the impact of the XEN implant on corneal astigmatism is important to better characterize the expected course of postoperative visual rehabilitation, the impact of novel glaucoma devices on corneal properties and the predictability of refractive outcomes after XEN implantation. Compared to traditional filtering surgery, the XEN Gel Stent is inserted without opening the conjunctiva and is implanted further from the corneal limbus (5 mm). These factors may allow for a reduced amount of surgically induced corneal astigmatism.
We hypothesize that the XEN Gel Stent implantation induces less corneal astigmatism compared to traditional filtering surgery, such as the trabeculectomy and GDDs (BGI or AGV).
The main goal of this prospective interventional comparative study is to assess the severity of postoperative corneal astigmatism induced by implantation of the XEN Gel Stent compared to that induced by traditional filtering surgery (trabeculectomy and GDDs).
Secondary objectives are evaluation of visual acuity recovery as well as IOP reduction and other parameters between groups.
Glaucoma surgery (XEN Gel Stent, trabeculectomy or GDD implantation) will be performed by the ophthalmologists in charge of the study according to standard procedures. For each patient, the most appropriate type of glaucoma surgery will be recommended by the ophthalmologist regardless of patients' participation in the study, as dictated by the specific nature of their glaucoma and following current standards of care.
924 studies on the registry are indexed under Glaucoma, Open-Angle; 117 are open to participants now.
This study's enrollment of 50 is below the median of 80 across 692 interventional studies indexed under Glaucoma, Open-Angle.
Browse Glaucoma, Open-Angle studies →Centre hospitalier de l'Université de Montréal (CHUM) is the lead sponsor of 376 studies on the registry; 110 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants suffering from glaucoma who are candidates for XEN Gel Stent implantation
Diagnostic Test: Corneal topography: OPD-Scan · Diagnostic Test: Corneal topography: Pentacam
Participants suffering from glaucoma who are candidates for trabeculectomy
Diagnostic Test: Corneal topography: OPD-Scan · Diagnostic Test: Corneal topography: Pentacam
Participants suffering from glaucoma who are candidates for GDD implantation (BGI or AGV)
Diagnostic Test: Corneal topography: OPD-Scan · Diagnostic Test: Corneal topography: Pentacam
Corneal topography photography, taken by specular reflection (OPD-Scan) by measuring corneal curvature, thickness and topography.
Corneal topography photography, taken by Scheimpflug imaging (Pentacam) by measuring corneal curvature, thickness and topography.
Keratometric values (OPD-Scan)
Change in simulated keratometric (K) values obtained by OPD-Scan between the indicated timepoints.
Time frame: Baseline, 2 months, 6 months, 12 months
Keratometric values (Pentacam)
Change in simulated keratometric (K) values obtained by Pentacam between the indicated timepoints.
Time frame: Baseline, 2 months, 6 months, 12 months
Best-corrected visual acuity change
Evaluation of visual acuity change, measured using the Snellen chart.
Time frame: Baseline, 2 months, 6 months, 12 months
Intraocular pressure change
Evaluation of intraocular pressure control, measured using gold standard Goldmann applanation tonometry.
Time frame: Baseline, 2 months, 6 months, 12 months
Visual field change change
Evaluation of visual field change. Visual field change will be calculated using the mean deviation (MD) values and pattern standard deviation (PSD) values measured using automated Humphrey 24-2 perimetry.
Time frame: Baseline, 6 months, 12 months
Retinal nerve fiber layer thickness change
Evaluation of retinal nerve fiber layer (RNFL) thickness change (µm), using the average RNFL thickness values measured using Spectral Domain Optical Coherence Tomography (SD-OCT). The change in thickness (µm) will be calculated between the time points described.
Time frame: Baseline, 6 months, 12 months
Ganglion cell layer thickness change
Evaluation of ganglion cell layer (GCL+) thickness. This GCL+ thickness is measured using the values for the average ganglion cell layer and inner plexiform layer thickness of the retina (value called "Average GCL + IPL thickness") obtained by Spectral Domain Optical Coherence Tomography (SD-OCT). The change in thickness (µm) will be calculated between the time points described.
Time frame: Baseline, 6 months, 12 months
Plan to share: No
Ran from Nov 2020 to primary completion in Apr 2024, 40 months.
Of 100 non-industry interventional studies with no phase under Glaucoma, Open-Angle, half reached primary completion within 35 months of starting (the median), counting those still running; a quarter within 16 and three quarters within 57. This study's 40 months is above that.
Counting every sponsor, half of 170 studies reached it within 35 months; a quarter within 19 and three quarters within 61.
How these figures are worked out, and which studies are left out of them.
This study is completed, as verified in Aug 2024. You cannot join it, but the record below documents what was studied.
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