Intraocular pressure (IOP) is a elementary data in diagnosis and therapy of glaucoma. Many studies have confirmed that most tonometry, including Goldmann applanation tonometry, are influenced by central corneal thickness (CCT) and CCT varies greatly among the general population. As a result, the measurement of CCT has a great implication in management of glaucoma. Further, CCT is confirmed a risk factor for progression from ocular hypertension to primary open angle glaucoma. The idea of that CCT may bear an inverse relation with the risk for developing glaucoma damage is in debating. Many specialists bring forward that CCT measurement should be one of the regular examinations in treatment of glaucoma patients.