Tonometry is a quick and simple test that checks the pressure inside your eyes. The results can help your doctor see if you're at risk for glaucoma. Glaucoma is a disease in which the nerve of the eye (the optic nerve) is gradually damaged over time, resulting in a loss of vision.

What does eye pressure tell you?

Intraocular pressure (IOP) is the pressure in your eyes. When that pressure is higher than normal, it causes ocular hypertension. While ocular hypertension isn't an eye disease in itself, it is an indication that you could develop glaucoma. Your eye pressure is measured in millimeters of mercury, expressed as mm Hg.

Why do opticians test the pressure in the eye?

Your eye doctor will want to check your eye pressure at every visit, to make sure other signs of glaucoma do not develop. Glaucoma is a serious eye disease that may result in vision loss if not treated early.