Goldmann Applanation Tonometry, Dynamic Contour Tonometry, and Corvis ST Tonometer

Study Overview
=================
Brief Summary
-----------------
The study is investigating Intra ocular pressure (IOP) by Goldmann Applanation Tonometry, Dynamic Contour Tonometry, and the Corvis ST tonometer.

Detailed Description
-----------------
The aim of the study is to approach the true Intra ocular pressure (IOP) by correlating the difference between IOP by Goldmann Applanation Tonometry to the IOP by Dynamic Contour Tonometry to the biomechanical parameters of the cornea measured by Corvis ST. Therefore the investigators gain new findings about the influence of the biomechanical corneal parameters on the IOP. In order to do so the investigators want to examine 50 Glaucoma eyes and 50 non-Glaucoma Eyes with Goldmann Applanation Tonometry, Dynamic Contour Tonometry, and Corvis ST.

Official Title
-----------------
Comparison of Intraocular Pressure Measured by Goldmann Applanation Tonometry and Dynamic Contour Tonometry vs. Corvis ST Tonometer

Conditions
-----------------
Glaucoma

Intervention / Treatment
-----------------
* Device: Measurement of intraocular pressure (IOP)


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria for the glaucoma group: diagnosis of glaucoma 18 years old or older with no upper limit Exclusion Criteria for the glaucoma group: IOP lowering surgery within the last 3 weeks any corneal surgery in the past bad fixation insufficient measurement quality with any of the study devices Inclusion Criteria for the healthy control group: no diagnosis of glaucoma 18 years old or older with no upper limit Exclusion Criteria for the healthy control group: any diagnosis of glaucoma IOP lowering surgery within the last 3 weeks any corneal surgery in the past bad fixation insufficient measurement quality with any of the study devices

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Diagnostic
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Glaucoma Eyes<br>Measurement of intraocular pressure (IOP) | Device: Measurement of intraocular pressure (IOP)<br>* Measurement of IOP with the following devices: (1) Goldmann tonometer, (2) Dynamic Contour tonometer, and (3) Corvis ST tonometer<br>|
| Active Comparator: Healthy Eyes<br>age-matched healthy eyes as controls will undergo Measurement of intraocular pressure (IOP) | Device: Measurement of intraocular pressure (IOP)<br>* Measurement of IOP with the following devices: (1) Goldmann tonometer, (2) Dynamic Contour tonometer, and (3) Corvis ST tonometer<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Delta IOP | IOP difference of Goldmann tonometer and Dynamic Contour tonometer | baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation of IOP difference of Goldmann tonometer and Dynamic Contour tonometer with biomechanical corneal properties measured by Corvis ST tonometer | Corvis ST has an integrated high-speed Scheimpflug camera which records images on which basis the biomechanical corneal parameter are analyzed (corneal thickness in micrometers, corneal applications in millimeters, peak distance in millimeters, radius in millimeters, and deformation amplitude in millimeters). Those biomechanical parameters of the cornea will be correlated to the difference of the IOP measured by GAT and by DCT (GAT - DCT). | baseline | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Glaucoma, Intraocular Pressure