A pachymeter is a medical device used to measure the thickness of the eye's cornea. It is used prior to LASIK surgery, and is useful in screening for patients suspected of developing glaucoma.

It is useful in monitoring the progression of certain disorders that cause the cornea to become thickened (or filled with water), resulting in a loss of vision. Pachymetry is also performed to determine whether the cornea is strong enough for procedures such as LASIK.