Applanation tonometry is a diagnostic procedure used to measure the pressure inside the eye, known as intraocular pressure (IOP). This test is important for detecting conditions like glaucoma, which can lead to vision loss if not treated. During the procedure, a small probe gently flattens a specific area of the cornea, and the amount of force required to achieve this flattening is measured. The procedure is typically quick and can be performed in a doctor's office. Patients may receive numbing eye drops to ensure comfort during the test. Accurate IOP measurements help eye care professionals assess eye health and determine appropriate treatment options.