What is the test?
Tonometry is a test to measure pressure in your eyeball. High pressure inside the eye is caused by a disease called glaucoma, which can damage your vision if it is not treated.
How do I prepare for the test?
Remove any contact lenses. Tell your doctor if you have an eye infection or other type of eye problem.
What happens when the test is performed?
The pressure inside your eye is always measured from the outside. In most cases, if you are at an eye clinic, the pressure can even be measured without anything actually touching your eye. The eye doctor has you look up close at an instrument that blows a small puff of air onto your eye. It then uses a special sensor (like a tiny radar detector) to detect the amount of indentation that the air puff causes on the surface of the eye. This indentation is normal and lasts for only a fraction of a second.