What is Pachymetry (CCT)? - Glaucoma Glossary

Pachymetry is a diagnostic procedure that measures the Central Corneal Thickness (CCT), typically utilizing ultrasound or optical technology.

What it means for the patient

This very quick test measures how thick the clear front window of your eye is. This is crucial because a thick or thin cornea acts like a thick or thin tire, tricking the pressure machine and resulting in artificially high or low eye pressure readings.

Clinical significance

Based on the landmark OHTS study, a thin CCT (<555 µm) is an independent risk factor for primary open-angle glaucoma development. Furthermore, applying an Ehlers 1975 CCT correction is mathematically necessary to uncover true, biologically accurate IOP.

How it is tracked

CCT is logged as a patient biometric. Glaucoma One automatically applies the Ehlers formula to standardize all raw IOP measurements into True Corrected IOP.