Question: What is tonometry and how is it used to diagnose glaucoma?
Answer: Tonometry refers to the technique of measuring the intraocular pressure, or eye pressure. The usual way or standard method that is typically employed is something called Goldmann applanation tonometry. After putting in a numbing drop, and in that usually it contains a fluorescent dye called Fluorescein, and under a cobalt blue light, which is commonly referred to as the blue light, a small probe will contact with the surface of your eye and that contact will allow measurement of the eye pressure. There are two other methods which are sometimes used to measure pressure.
One is called a tono pen, which looks like a large marker, but on the tip of it is a very small applanation point or point in which of contact with the eye that can measure the pressure as well or something called pneumotonometry which involves contacting the eye with something that resembles an air piston; that these are both methods that can measure the intraocular pressure. However Goldmann applanation tonometry is the standard method that is usually employed. Once you have the eye pressure measurement, if the pressure is elevated this is a very suspicious [risk factor] for glaucoma.