Validation of Retinal Oximetry in Glaucoma Patients: a Structural and Functional Correlation

Study Overview
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Brief Summary
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Retinal ischemia is thought to play an important role in the pathogenesis of glaucoma. Up until today, very little is known about the metabolic alterations in the retina of glaucoma patients, since only techniques for surrogate measurements of metabolism (like blood flow velocities and vessel diameter) were available. Oximetry has provided us with an important tool to study metabolism in glaucoma, and to correlate these findings with the available blood flow evaluation techniques. Preliminary results by the group of Prof Stefánsson (2011) with the dual wavelength oximeter pointed out that deeper glaucomatous visual field defects are associated with decreased arteriovenous differences in retinal oxygen saturation. These data suggest that a change in oxygen metabolism occurs in glaucomatous retina. This reduced oxygen metabolism may be related to tissue atrophy. However, this explanation is still hypothetical, since the relation between these oximetry results and structural changes in the optic nerve have not been studied yet. What are the oximetry values in a normal population of within the same age group as the glaucoma population? To answer this question, a normative database of the investigators retinal oximetry device needs to be constructed for healthy controls. Do glaucoma patients have different retinal oximetry values than these normal patients? Are there any differences in retinal oxygenation between these glaucoma groups? To answer these questions, oximetry measurements will be performed in patients with normal tension glaucoma (NTG) and primary open angle glaucoma (POAG). Is there an association between structural optic disc and retinal nerve fibre layer changes, using Heidelberg Retinal Tomography (HRT), with alterations in retinal vascular oxygen saturation in NTG and POAG patients? Are blood flow measurements, using colour Doppler imaging (CDI), correlated with alteration in retinal vascular oxygen in NTG and POAG patients?

Detailed Description
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Oximetry pictures will be taken and analysed. CDI exam will be performed. Visual field examen will be performed. HRT will be performed.

Official Title
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Validation of Retinal Oximetry in Glaucoma Patients: a Structural and Functional Correlation

Conditions
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Open Angle Glaucoma, Low Tension Glaucoma

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: individuals over 18 years old willing to sign an informed consent and able to comply with the requirements of the study having no other ocular diseases besides glaucoma Exclusion Criteria: history of ocular trauma intraocular surgery (except for cataract surgery) eye disease (except glaucoma) systemic diseases with ocular involvement like diabetes

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 |
| --- | --- |
| healthy age machted controls<br> | |
| normal tension glaucoma patients<br> | |
| primary open angle glaucoma patients<br> | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Comparison of oxygen saturation between glaucoma patients and healthy controls. | Retinal oximetry gives us oxygen saturation values who will be compared between glaucoma patients and healthy controls and will be correlated to visual field mean defect, structure parameters from the HRT and velocity measurements with the CDI. | patients will be followed during their hospital stay, an average. of 3 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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oximetry, open angle glaucoma, low tension glaucoma