Ocular Rigidity and Outflow Facility in Glaucomatous and Normal Eyes

Study Overview
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Brief Summary
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Ocular rigidity characterizes the relationship between pressure and volume changes in the human eye and is expressed as a macroscopic coefficient. Outflow facility is a measure of the resistance of the conventional outflow pathway and represents a parameter that is of interest in glaucoma. Difficulties in the measurement of ocular rigidity in the living human eye have limited our knowledge on this parameter. However, ocular biomechanics have been implicated in the pathogenesis of this disease. The aim of this study is to characterize the pressure volume relation and quantify ocular rigidity and outflow facility in glaucomatous and normal eyes. For this purpose, the investigators have recently developed a manometric method for the measurement of ocular rigidity and outflow facility.

Official Title
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Measurement of Ocular Rigidity, Outflow Facility and Ocular Blood Flow in Glaucomatous and Normal Eyes

Conditions
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Glaucoma

Intervention / Treatment
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* Procedure: Ocular rigidity, outflow facility and intraocular pressure measurement


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with primary open or pseudoexfoliation glaucoma that are undergoing cataract surgery Patients undergoing cataract surgery without evidence of other ocular disease. Exclusion Criteria: Evidence of any ocular disease, other than specified in the inclusion criteria Previous ophthalmic surgery or trauma Significant visual field defect (MD<-12dB) or an increased cup to disc ratio (>0.9).

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 90 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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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Glaucoma Patients<br> | Procedure: Ocular rigidity, outflow facility and intraocular pressure measurement<br>* The measurement procedure includes cannulation of the anterior chamber of the eye, under sterile conditions. Infusion of the eye with microvolumes of a saline solution is performed, followed by manometric measurement of intraocular pressure, in order to quantify ocular rigidity. Outflow facility is estimated from recordings of intraocular pressure after the infusion is stopped.<br>|
| Active Comparator: Control subjects<br> | Procedure: Ocular rigidity, outflow facility and intraocular pressure measurement<br>* The measurement procedure includes cannulation of the anterior chamber of the eye, under sterile conditions. Infusion of the eye with microvolumes of a saline solution is performed, followed by manometric measurement of intraocular pressure, in order to quantify ocular rigidity. Outflow facility is estimated from recordings of intraocular pressure after the infusion is stopped.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ocular rigidity coefficient |  | 2 minutes measurement of ocular rigidity | 
| Outflow facility coefficient |  | 3-4 minutes measurement of outflow facility | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ocular pulse amplitude |  | 6 minutes | 
| Pulsatile ocular blood flow |  | 6 minutes |