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.

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