With contact tonometry, a tiny probe is used to gently flatten a portion of the cornea to measure the pressure in the patient's eye; while the slit lamp is used to view the eye. Eye pressure is quantified by calculating the amount of pressure used to flatten the cornea.
Applanation tonometry
In applanation tonometry, intraocular pressure (IOP) is inferred from the force required to flatten (flatten) a constant area of the cornea, according to the Imbert-Fick law. The Maklakoff tonometer was an early example of this method, while the Goldmann tonometer is the version most used in current practice, because the probe comes into contact with the cornea, a topical anesthetic, such as proxymetacaine, is introduced into the eye surface in the form of an eyedrop.
