How can corneal thickness affect the accuracy of my eye-pressure reading?

Researchers have discovered that the thickness of your cornea (the clear part of the eye's protective covering) plays a role in the interpretation of your eye pressure reading. People with thin corneas (less than 540 micrometers) show artificially low intraocular pressure readings, which can be a concern particularly if your doctor fails to adjust the pressure reading upwards for your corneal thickness. On the other hand, people with thick corneas (greater than 540 microns) show artificially high pressure readings, which could lead to unnecessary treatment (unless your doctor interprets the eye pressure reading in the context of your corneal thickness, optic nerve health, visual field, and other risk factors). Fortunately, there is a quick, painless test, called a pachymetry test, to measure corneal thickness. The measurement (done routinely with pressure screenings) enables your doctor to better understand your intraocular pressure readings and develop an appropriate treatment plan.