Biomechanical Changes After Trabeculectomy

Study Overview
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Brief Summary
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Corneal biomechanics are studied in glaucoma patients prior and at least 6 month after trabeculectomy.

Detailed Description
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Prior to trabeculectomy corneal biomechanics are measured with the Ocular Response Analyzer (ORA, Reichert) and the Corvis st (Oculus). Both instruments work with an air-puff which deforms the cornea. Intraocular pressure is measured like in non-contact air-puff tonometry. The ORA also measures corneal hysteresis (CH) and the corneal resistance factor (CRF) which are qualitative measures of corneal biomechanics. The Corvis is a high-speed Scheimpflug-camera (4330 frames/sec) that records the quantitative movements of the cornea. At least 6 month after uncomplicated trabeculectomy the measurements are repeated.

Official Title
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Corneal Biomechanical Changes Following Trabeculectomy

Conditions
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Glaucoma, Primary

Intervention / Treatment
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* Procedure: trabeculectomy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Glaucoma patients in need of further IOP-reduction despite maximally tolerated therapy and assigned for trabeculectomy. Minimum of 18 years. Exclusion Criteria: Corneal pathologies.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Glaucoma, primary<br>Glaucoma patients undergoing trabeculectomy | Procedure: trabeculectomy<br>* Standard trabeculectomy with the use of antimetabolites (mitomycin C) for glaucoma patients with insufficient intraocular pressure (IOP) control taking maximally tolerated IOP-reducing medication, visual field progression despite maximally tolerated IOP-reducing medication, adverse events because of maximally tolerated IOP-reducing medication or nono.compliance.<br>* Other names: filtering glaucoma surgery;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Corneal biomechanical changes following trabeculectomy | Evaluation of biomechanical properties of the cornea before and after trabeculectomy to evaluate whether intraocular pressure is accurately measured after trabeculectomy. Corneal hysteresis and corneal resistance factor as measured with the Ocular Response Analyzer and the corneal deformation response to an air-puff as measured with an ultra-high-speed Scheimpflug camera are assessed. | 2-3 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Intraocular pressure after trabeculectomy | Intraocular pressure is measured with 3 different devices (Goldmann applanation tonometry, Ocular Response Analyzer, Corvis st) prior and at least 6 month after trabeculectomy. | 2-3 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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trabeculectomy, open angle glaucoma, corneal biomechanics