Influence of Central Corneal Thickness on Intraocular Pressure Measurements With The Pneumotonometer and Goldmann Applanation Tonometer

To compare intraocular pressure (IOP) measurements of Goldmann applanation tonometer and pneumotonometer with respect to central corneal thickness in eyes with normal intraocular pressure. Comparative study. IOP was measured with an pneumotonometer(NCT) and Goldmann applanation tonometer(GAT) in random order in 164 eyes(82 patients) with normal intraocular pressure. Central corneal thickness (CCT) was measured using an ultrasonic pachymeter after all IOP determinations had been made. Right and left eyes were analyzed separately for statistical purposes. In corneas with varying CCT, IOP measured with pneumotonometer showed higher values with thicker corneas and lower values with thinner corneas compared to Goldman applanation tonometer. IOP measured with pneumotonometer showed a significant variation with respect to central corneal thickness when compared to Goldman applanation tonometer which is a more reliable method of IOP measurement. Still pneumotonometer can be used for screening purposes for large crowds, since it is faster and easier to record IOP. In patients with suspicious disc changes, IOP measurements have to be reconfirmed with GAT so that diagnosis of glaucoma is not missed.