Just recently studies on glaucoma have emphasised the significance of intraocular pressure in the diagnosis of glaucoma and the importance of intraocular pressure reduction in the management of glaucoma. Central corneal thickness appears to play an important role in the exact measurement of intraocular pressure and in the diagnostic assessment of glaucoma. Numerous studies have verified that corneal thickness shows systematic differences in different forms of glaucoma. Since deviations of corneal thickness from normal can possibly result in an artificial change of Goldmann applanation values, it would be a most important source of error in the diagnosis of glaucoma to ignore central corneal thickness. Corrections of intraocular pressure measured with applanation tonometry can be achieved in various ways but there is considerable divergence in the results. The absence of a generally accepted algorithm for the correction of intraocular pressure measured with applanation tonometry should not prevent us from a wide application of pachymetry, since it delivers valuable additional information on the individual risk of glaucoma.