Comparison of Rebound Tonometer, Non-Contact Tonometer, Goldmann Applanation Tonometer and the Relationship to Central Corneal Thickness

ABSTRACT

PURPOSE: To compare the level of accuracy of intraocular pressure (IOP) measurements of a rebound tonometer (RT) Icare(R), and non-contact tonometer (NCT), using Goldmann Applanation tonometer (GAT) as a reference to evaluate the influence of central corneal thickness (CCT) on IOP readings in the Korean population. METHODS: In a prospective study of 273 eyes, IOP was measured with RT, GAT, and NCT and compared to CCT measurements. Patients were assigned to one of 3 groups based on IOP measurements of GAT and 1 of 2 groups based on CCT. The comparison of the IOP values of RT, GAT, and NCT was performed between the IOP and CCT groups, and the differences among tonometers were evaluated. RESULTS: The RT showed statistically significant correlation with the GAT compared to the NCT. The CCT was related to RT measurements. The RT values compared to the GAT was underestimated in thin corneas and overestimated in thick corneas. CONCLUSIONS: There was a significant correlation between the RT and the GAT measurements compared with the NCT. However, RT is influenced by CCT and correlates less with GAT in low IOP ranges, suggesting that corneal thickness should be taken into consideration during such measurements.