Glaucoma Screening & Tonometry

Testing for glaucoma typically begins with measuring the pressure inside your eyes. A tonometer measures the pressure in your eyes to help determine whether you have glaucoma. A common glaucoma test is the “puff-of-air” test, technically known as non-contact tonometry, or NCT.

The test begins with you putting your chin on the machine’s chin rest. While you look at a light inside the machine, the doctor or a trained assistant will puff a small burst of air at your open eye. It is completely painless, and the tonometer does not touch your eye.

Based on your eye’s resistance to the puff of air, the machine calculates your intraocular pressure (IOP). If you have high eye pressure, you may be at risk for or have glaucoma. You typically have no warning signs of glaucoma until you already have significant vision loss. For this reason, routine eye exams that include tonometry are essential to rule out early signs of glaucoma and protect your eyesight.