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

University of Zurich109 enrolled

Overview

The study is investigating Intra ocular pressure (IOP) by Goldmann Applanation Tonometry, Dynamic Contour Tonometry, and the Corvis ST tonometer.

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.

Study Type

INTERVENTIONAL

Allocation

NON_RANDOMIZED

Purpose

DIAGNOSTIC

Masking

NONE

Enrollment

109

Conditions

Glaucoma

Interventions

Measurement of intraocular pressure (IOP)DEVICE

Measurement of IOP with the following devices: (1) Goldmann tonometer, (2) Dynamic Contour tonometer, and (3) Corvis ST tonometer

Eligibility

Sex: ALLMin age: 18 YearsHealthy volunteers:

Medical Language ↔ Plain English

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

Outcomes

Primary Outcomes

Delta IOP

IOP difference of Goldmann tonometer and Dynamic Contour tonometer

Time frame: baseline

Secondary Outcomes

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).

Time frame: baseline

Data from ClinicalTrials.gov

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