Glaucoma, Open-AngleTopo-XENNCT04602923
Keratometric Change After XEN, Trabeculectomy and Tube Shunts
A study testing Corneal topography: OPD-Scan and Corneal topography: Pentacam in people with Glaucoma, Open-Angle and Glaucoma, Angle-Closure, run by Centre hospitalier de l'Université de Montréal (CHUM) at 1 site in Canada.
Trial summary
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). Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Glaucoma, Open-Angle, Glaucoma, Angle-Closure, Glaucoma Secondary
- What is being tested?
- Corneal topography: OPD-Scan and Corneal topography: Pentacam
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 50 participants
- Where
- 1 siteCanada
- Study dates
- 4 Nov 2020to 7 Aug 2024
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Eyes with an IOP above target and/or progressing on maximally tolerated medical therapy;
- Patients aged 18 years or older;
- Ability to provide informed consent;
- Ability to be followed for the entire duration of the study.
Who cannot join
- Patients less than 18 years old;
- Inability to provide informed consent;
- Inability to be followed for the entire duration of the study;
- Patients undergoing surgery combined with cataract extraction;
- Presence of severe dry eye disease;
- Presence of ocular comorbidities other than glaucoma, such as corneal or retinal disease.
Trial locations and contacts
1 site in 1 country.
Canada1 site
Centre Hospitalier de l'Université de Montréal (CHUM)
Montreal, Quebec, H2X 3E4
About this study
Official title: Comparison of Keratometric Change After Xen Gel Stent Implantation, Trabeculectomy, and Tube Shunts
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.
Read the detailed description
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.
- Being tested
- Corneal topography: OPD-Scan, Corneal topography: Pentacam
- Keywords
- Glaucoma drainage devices, Xen Gel Stent, Baerveldt glaucoma implant, Ahmed glaucoma implant, Trabeculectomy
- Medical subject headings
- Glaucoma, Open-Angle, Glaucoma, Angle-Closure
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Corneal topography: OPD-ScanDiagnostic test
Corneal topography photography, taken by specular reflection (OPD-Scan) by measuring corneal curvature, thickness and topography.
Corneal topography: PentacamDiagnostic test
Corneal topography photography, taken by Scheimpflug imaging (Pentacam) by measuring corneal curvature, thickness and topography.
| Study group | Role | What they receive |
|---|---|---|
| XEN Gel Stent implantation | Experimental | Participants suffering from glaucoma who are candidates for XEN Gel Stent implantation Receives: Diagnostic Test: Corneal topography: OPD-Scan; Diagnostic Test: Corneal topography: Pentacam |
| Trabeculectomy | Experimental | Participants suffering from glaucoma who are candidates for trabeculectomy Receives: Diagnostic Test: Corneal topography: OPD-Scan; Diagnostic Test: Corneal topography: Pentacam |
| GDD implantation | Experimental | Participants suffering from glaucoma who are candidates for GDD implantation (BGI or AGV) Receives: Diagnostic Test: Corneal topography: OPD-Scan; Diagnostic Test: Corneal topography: Pentacam |
What is being measured
The primary outcome is the main question the study is designed to answer.
Keratometric values (OPD-Scan)
Change in simulated keratometric (K) values obtained by OPD-Scan between the indicated timepoints.
Measured: Baseline, 2 months, 6 months, 12 months
Keratometric values (Pentacam)
Change in simulated keratometric (K) values obtained by Pentacam between the indicated timepoints.
Measured: Baseline, 2 months, 6 months, 12 months
Secondary outcomes (5)
Best-corrected visual acuity change
Evaluation of visual acuity change, measured using the Snellen chart.
Measured: Baseline, 2 months, 6 months, 12 months
Intraocular pressure change
Evaluation of intraocular pressure control, measured using gold standard Goldmann applanation tonometry.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: Baseline, 6 months, 12 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Oct 2020
- Study start4 Nov 2020
- Primary completion1 Apr 2024
- Study completion7 Aug 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (9)Papers the sponsor has linked to this study.
- Other trials for Glaucoma, Open-AngleStudies of the same condition, open and under way.
- More trials run by Centre hospitalier de l'Université de Montréal (CHUM)The sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Factorial
- Model description
- 3 groups will be compared: * Group 1: 30 participants suffering from glaucoma who are candidates for XEN Gel Stent implantation * Group 2: 30 participants suffering from glaucoma who are candidates for trabeculectomy * Group 3: 30 participants suffering from glaucoma who are candidates for GDD implantation (BGI or AGV)
- Masking
- None (open label)
- Enrolment
- 50 participants (actual)
Sponsor and investigators
- Sponsor type
- University, hospital or other
- Collaborators
- Allergan
- Responsible party
- Sponsor
- Investigators
- Georges Durr, MD, FRCSC, Principal investigator, Centre hospitalier de l'Université de Montréal (CHUM)
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04602923
- Sponsor's protocol ID
- 20.240
- Acronym
- Topo-XEN
- Status last verified
- Aug 2024
- First submitted
- 21 Oct 2020
- Last updated
- 9 Aug 2024
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Quigley HA, Broman AT. The number of people with glaucoma worldwide in 2010 and 2020. Br J Ophthalmol. 2006 Mar;90(3):262-7. doi: 10.1136/bjo.2005.081224.
PubMed 16488940Banitt M. Evaluation and management of glaucoma after keratoprosthesis. Curr Opin Ophthalmol. 2011 Mar;22(2):133-6. doi: 10.1097/ICU.0b013e328343723d.
PubMed 21191292Saheb H, Ahmed II. Micro-invasive glaucoma surgery: current perspectives and future directions. Curr Opin Ophthalmol. 2012 Mar;23(2):96-104. doi: 10.1097/ICU.0b013e32834ff1e7.
PubMed 22249233Lavia C, Dallorto L, Maule M, Ceccarelli M, Fea AM. Minimally-invasive glaucoma surgeries (MIGS) for open angle glaucoma: A systematic review and meta-analysis. PLoS One. 2017 Aug 29;12(8):e0183142. doi: 10.1371/journal.pone.0183142. eCollection 2017.
PubMed 28850575Chatzara A, Chronopoulou I, Theodossiadis G, Theodossiadis P, Chatziralli I. XEN Implant for Glaucoma Treatment: A Review of the Literature. Semin Ophthalmol. 2019;34(2):93-97. doi: 10.1080/08820538.2019.1581820. Epub 2019 Feb 21.
PubMed 30789072Chan HHL, Kong YXG. Glaucoma surgery and induced astigmatism: a systematic review. Eye Vis (Lond). 2017 Nov 17;4:27. doi: 10.1186/s40662-017-0090-x. eCollection 2017.
PubMed 29177182Pakravan M, Alvani A, Esfandiari H, Ghahari E, Yaseri M. Post-trabeculectomy ocular biometric changes. Clin Exp Optom. 2017 Mar;100(2):128-132. doi: 10.1111/cxo.12477. Epub 2016 Sep 29.
PubMed 27686794Koivusalo R, Valimaki J. Effect of glaucoma drainage implant surgery on corneal topography: a prospective study. Acta Ophthalmol. 2020 May;98(3):305-309. doi: 10.1111/aos.14247. Epub 2019 Sep 8.
PubMed 31495070Miraftabi A, Lotfi M, Nilforushan N, Abdolalizadeh P, Jafari S. Ocular biometric changes after Ahmed glaucoma valve implantation. Eur J Ophthalmol. 2021 Jan;31(1):120-124. doi: 10.1177/1120672119889528. Epub 2019 Nov 21.
PubMed 31752527
Study at a glance
From the registry record, last updated by the sponsor on 9 Aug 2024. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Comparison of Keratometric Change After Xen Gel Stent Implantation, Trabeculectomy, and Tube Shunts
- ClinicalTrials.gov ID
- NCT04602923
- Acronym / sponsor ID
- Topo-XEN / 20.240
- Keywords
- Glaucoma drainage devices, Xen Gel Stent, Baerveldt glaucoma implant, Ahmed glaucoma implant, Trabeculectomy
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 50 participants (actual)
- Lead sponsor
- Centre hospitalier de l'Université de Montréal (CHUM)University, hospital or other
- Collaborators
- Allergan
- Study start
- 4 Nov 2020 (actual)
- Primary completion
- 1 Apr 2024 (actual)
- Study completion
- 7 Aug 2024 (actual)
- First posted
- 26 Oct 2020 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
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.
Study design
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Factorial
- Masking
- None (open label)
- Number of arms
- 3
- Model description
- 3 groups will be compared: * Group 1: 30 participants suffering from glaucoma who are candidates for XEN Gel Stent implantation * Group 2: 30 participants suffering from glaucoma who are candidates for trabeculectomy * Group 3: 30 participants suffering from glaucoma who are candidates for GDD implantation (BGI or AGV)
| Arm | Type | Receives |
|---|---|---|
| XEN Gel Stent implantation | Experimental | Diagnostic Test: Corneal topography: OPD-Scan, Diagnostic Test: Corneal topography: PentacamParticipants suffering from glaucoma who are candidates for XEN Gel Stent implantation |
| Trabeculectomy | Experimental | Diagnostic Test: Corneal topography: OPD-Scan, Diagnostic Test: Corneal topography: PentacamParticipants suffering from glaucoma who are candidates for trabeculectomy |
| GDD implantation | Experimental | Diagnostic Test: Corneal topography: OPD-Scan, Diagnostic Test: Corneal topography: PentacamParticipants suffering from glaucoma who are candidates for GDD implantation (BGI or AGV) |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Eyes with an IOP above target and/or progressing on maximally tolerated medical therapy;
- Patients aged 18 years or older;
- Ability to provide informed consent;
- Ability to be followed for the entire duration of the study.
Key exclusion criteria (6 listed)
- Patients less than 18 years old;
- Inability to provide informed consent;
- Inability to be followed for the entire duration of the study;
- Patients undergoing surgery combined with cataract extraction;
- Presence of severe dry eye disease;
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Corneal topography: OPD-ScanCorneal topography photography, taken by specular reflection (OPD-Scan) by measuring corneal curvature, thickness and topography. | Diagnostic test | GDD implantation, Trabeculectomy, XEN Gel Stent implantation |
| Corneal topography: PentacamCorneal topography photography, taken by Scheimpflug imaging (Pentacam) by measuring corneal curvature, thickness and topography. | Diagnostic test | GDD implantation, Trabeculectomy, XEN Gel Stent implantation |
Primary outcome
Keratometric values (OPD-Scan)
Time frame: Baseline, 2 months, 6 months, 12 months
Change in simulated keratometric (K) values obtained by OPD-Scan between the indicated timepoints.
Keratometric values (Pentacam)
Time frame: Baseline, 2 months, 6 months, 12 months
Change in simulated keratometric (K) values obtained by Pentacam between the indicated timepoints.
5 secondary outcomes
Best-corrected visual acuity change
Time frame: Baseline, 2 months, 6 months, 12 months
Intraocular pressure change
Time frame: Baseline, 2 months, 6 months, 12 months
Visual field change change
Time frame: Baseline, 6 months, 12 months
Retinal nerve fiber layer thickness change
Time frame: Baseline, 6 months, 12 months
Ganglion cell layer thickness change
Time frame: Baseline, 6 months, 12 months
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 Aug 2024.
- Background: PubMed 16488940Quigley HA, Broman AT. The number of people with glaucoma worldwide in 2010 and 2020. Br J Ophthalmol. 2006 Mar;90(3):262-7. doi: 10.1136/bjo.2005.081224.
- Background: PubMed 21191292Banitt M. Evaluation and management of glaucoma after keratoprosthesis. Curr Opin Ophthalmol. 2011 Mar;22(2):133-6. doi: 10.1097/ICU.0b013e328343723d.
- Background: PubMed 22249233Saheb H, Ahmed II. Micro-invasive glaucoma surgery: current perspectives and future directions. Curr Opin Ophthalmol. 2012 Mar;23(2):96-104. doi: 10.1097/ICU.0b013e32834ff1e7.
- Background: PubMed 28850575Lavia C, Dallorto L, Maule M, Ceccarelli M, Fea AM. Minimally-invasive glaucoma surgeries (MIGS) for open angle glaucoma: A systematic review and meta-analysis. PLoS One. 2017 Aug 29;12(8):e0183142. doi: 10.1371/journal.pone.0183142. eCollection 2017.
- Background: PubMed 30789072Chatzara A, Chronopoulou I, Theodossiadis G, Theodossiadis P, Chatziralli I. XEN Implant for Glaucoma Treatment: A Review of the Literature. Semin Ophthalmol. 2019;34(2):93-97. doi: 10.1080/08820538.2019.1581820. Epub 2019 Feb 21.
- Background: PubMed 29177182Chan HHL, Kong YXG. Glaucoma surgery and induced astigmatism: a systematic review. Eye Vis (Lond). 2017 Nov 17;4:27. doi: 10.1186/s40662-017-0090-x. eCollection 2017.
- Background: PubMed 27686794Pakravan M, Alvani A, Esfandiari H, Ghahari E, Yaseri M. Post-trabeculectomy ocular biometric changes. Clin Exp Optom. 2017 Mar;100(2):128-132. doi: 10.1111/cxo.12477. Epub 2016 Sep 29.
- Background: PubMed 31495070Koivusalo R, Valimaki J. Effect of glaucoma drainage implant surgery on corneal topography: a prospective study. Acta Ophthalmol. 2020 May;98(3):305-309. doi: 10.1111/aos.14247. Epub 2019 Sep 8.
- Background: PubMed 31752527Miraftabi A, Lotfi M, Nilforushan N, Abdolalizadeh P, Jafari S. Ocular biometric changes after Ahmed glaucoma valve implantation. Eur J Ophthalmol. 2021 Jan;31(1):120-124. doi: 10.1177/1120672119889528. Epub 2019 Nov 21.
- Individual participant dataSharing planned: No
Related trials for Glaucoma, Open-Angle
RecruitingPhase 2
A Phase 2a Study Comparing the Efficacy, Safety and Tolerability of Pregabalin Eye Drops Comparing With Timolol Eye Drops in Adults With Glaucoma or High Eye Pressure.
Primary Open - Angle Glaucoma (POAG), Ocular Hypertension (OHT)
Recruiting
The Acute Effect of Exercise Type And Timing on Ambulatory Blood Pressure and Intra-Ocular Pressure in Individuals With Glaucoma (The ACHIEVE-project).
Glaucoma Open-Angle Primary, Hypertension
RecruitingPhase 4
Adaptive Optics OCT Evaluation of Rhopressa's Effects on the Retinal Ganglion Cells in Glaucoma Patients
Open Angle Glaucoma (OAG), Glaucoma
RecruitingObservational study
PRESERFLO™ MicroShunt XI Observational PMCF Study With no Control Group
Primary Open Angle Glaucoma
Active, not recruitingObservational study
Glaucoma, Visual Field Loss, and Their Association With Life Space in Older Adults
Primary Open Angle Glaucoma
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Georges Durr, MD, FRCSC principal investigator
Centre hospitalier de l'Université de Montréal (CHUM)
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Corneal topography: OPD-Scan and Corneal topography: Pentacam in people with Glaucoma, Open-Angle and Glaucoma, Angle-Closure, run by Centre hospitalier de l'Université de Montréal (CHUM) at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 9 Aug 2024. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Keratometric values (OPD-Scan) (time frame: Baseline, 2 months, 6 months, 12 months). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04602923, which also lists 9 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Aug 2024.