Assessment of Endothelial Glycocalyx in Patients With Primary Open-angle Glaucoma

Study Overview
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Brief Summary
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The glycocalyx is a fibrillary lining structure that covers the inner surface of blood vessels. Composed of glycoproteins and polysaccharides, it is an essential determinant of vascular endothelial physiology: it limits coagulation activation and adapts capillary perfusion. Studies have shown glycocalyx alteration in various vascular and autoimmune pathologies such as diabetes, high blood pressure, chronic renal failure, ischemic heart disease, stroke, dementia, septic shock, and several other inflammatory pathologies with a common basis in vascular insufficiency. Glaucoma is a progressive, chronic and asymptomatic optic neuropathy characterized by visual field damage and abnormalities of the optic nerve head. Two hypotheses have been proposed as a basis for this progressive damage: the mechanical theory, which explains the papillary excavation by a compression of the optic nerve head under the effect of high intraocular pressure; and the ischemic theory, explained by a circulatory insufficiency at the level of the blood capillaries of the retina and especially of the optic nerve head. This latter theory is related to several pathologies that have circulatory insufficiency as common underlying pathophysiology, and in which damage to the glycocalyx has been well studied. Glycocalyx damage has rarely been studied in glaucoma. Yang et al. showed that the glycocalyx, present in Schlem's canal, plays a major role in the transduction of shear stress and regulation of outflow resistance to the aqueous humor, which may constitute an interesting biomarker for glaucomatous pathologies.

Detailed Description
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This study propose to extend the exploration of the ischemic theory of glaucoma by a specific imaging technique (the GlycoCheck) which allows an assessment of the microvascular system integrity by giving a vitality score of this system. This score, known as the MicroVascular Health score (MVHS), depends on the following measured parameters: Capillary density (CD), Red blood cell filling Percent (RBF), and Perfused boundary region (PBR).

Official Title
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Assessment of Endothelial Glycocalyx in Patients With Primary Open-angle Glaucoma: a Prospective Single-center Cross-sectional Case-control Study

Conditions
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Primary Open-angle Glaucoma, Glaucoma

Intervention / Treatment
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* Procedure: Glycocheck
* Procedure: Ophthalmological examinations


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Express consent to participate in the study Only for case group: primary open angle glaucoma (defined as the presence of visual field damage attributed to glaucomatous optic neuropathy) in both eyes Only for control group: Absence optic nerve pathology (including primary open angle glaucoma) Exclusion Criteria: Pregnant or breastfeeding woman Sleep apnea Renal insufficiency Parkinson's disease Alzheimer's disease Antiphospholipid syndrome Cancer for which treatment ended less than 2 years ago Stroke less than 1 year ago Myocardial infarction less than 1 year ago

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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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Case group: primary open angle glaucoma<br> | Procedure: Glycocheck<br>* Assessment of the sublingual microvascularization<br>Procedure: Ophthalmological examinations<br>* Description : Measurement of best corrected distance visual acuity with ETDRS (Early Treatment Diabetic Retinopathy Study) Measurement of intraocular pressure by aplanation and forced air tonometer Central corneal thickness measurement with OCT (Optical Coherence Tomography) Non-mydriatic retinophotography Humphrey 24-2 visual field OCT-RNFL (Optical Coherence Tomography - retinal nerve fiber layer)<br>|
| Control group: No Absence of optic nerve pathology<br> | Procedure: Glycocheck<br>* Assessment of the sublingual microvascularization<br>Procedure: Ophthalmological examinations<br>* Description : Measurement of best corrected distance visual acuity with ETDRS (Early Treatment Diabetic Retinopathy Study) Measurement of intraocular pressure by aplanation and forced air tonometer Central corneal thickness measurement with OCT (Optical Coherence Tomography) Non-mydriatic retinophotography Humphrey 24-2 visual field OCT-RNFL (Optical Coherence Tomography - retinal nerve fiber layer)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Thickness of the Perfused boundary region (PBR) | Evaluated with the Glycocheck, in µm | Baseline day | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Glycocheck, Sublingual microvascularization, Glycocalyx, Primary Open-angle Glaucoma, Glaucoma