A study called the Ocular Hypertension Treatment Study (O.H.T.S.) identified central corneal thickness (C.C.T.) as an independent risk factor for development of glaucoma among people with elevated intraocular pressure. The cornea is the clear dome in the front of the eye and its thickness is measured using an ultrasound device called a pachymeter. Information determined by this test may help qualify a person’s risk of developing glaucoma.