This is the measurement of corneal thickness. The cornea is the clear window that makes up the front of the eye and allows light to enter the eye. The corneal thickness is an important measurement for a couple of reasons. An abnormally thin or thick cornea can affect pressure measurements when screening for glaucoma. With LASIK eye surgery, some of the cornea is removed with a laser in order to change the focus of the eye … if your cornea is too thin to begin with, you might not be a good candidate for LASIK. We measure the cornea with a machine called a “pachymeter” … it is a small ultrasonic probe that briefly touches the surface of the anesthetized eye. It only takes a few seconds to obtain this measurement and the process is painless. Corneal thickness is a relatively stable measurement and rarely changes with time unless you have problems with corneal swelling such as from Fuchs’ dystrophy.