How a Tonometry Test Can Be Done?
Goldmann applanation tonometry. This is done by using numbing eye drops with a fluorescent dye in them. After using these, the doctor presses a probe that emits blue light into the surface of the eye. The fluorescent dye is used to guide the doctor in knowing how much pressure is required to compress the cornea. The cornea is a transparent area located outside the eye. This can now be used to determine the intraocular pressure. Basically, the intraocular pressure is directly related to the force needed to press the cornea.
Non-contact tonometry. This test involves a device that blows a little air into the eye to compress the cornea [5]. A certain amount of air returns from the eye and it is measured by the device and is turned to an intraocular pressure measurement.
Tono-pen. This a portable device that is used to simply touch the surface of the eye. It is used to measure the force required to compress the cornea to determine the intraocular pressure. Similar to Goldmann applanation, your doctor administers numbing eye drop before the test is done. The development of more advanced technology is rendering this test archaic.
Icare tonometer. Just like the tono-pen, the icare tonometer is a portable device. The probe of the device is used to softly touch the cornea to know the intraocular pressure
depending on how much the probe rebounds. Your doctor may not administer drops in this test.