Only clear-sighted people will ace this test. Give it a try!
Screening for glaucoma
Tonometry measures the fluid pressure inside your eye (intraocular pressure). This is one test that helps your eye doctor detect glaucoma, a disease that damages the optic nerve.
Several methods to measure intraocular pressure are available, including:
Applanation tonometry. This test measures the amount of force needed to temporarily flatten a part of your cornea. You’ll be given eyedrops with fluorescein, the same dye used in a regular slit-lamp examination. You’ll also receive eyedrops containing an anesthetic.
Using the slit lamp, your doctor moves the tonometer to touch your cornea and determine the eye pressure. Because your eye is numbed, the test doesn’t hurt.
Noncontact tonometry. This method uses a puff of air to estimate the pressure in your eye. No instruments touch your eye, so you won’t need an anesthetic. You’ll feel a momentary pulse of air on your eye, which can be startling.