Comparison of Intraocular Pressure Measurements Between Goldmann Applanation Tonometry and Reichert 7 Noncontact Tonometry

Abstract

Purpose:The aim of this study was to compare the Reichert 7 (R7) noncontact tonometry with Goldmann applanation tonometry (GAT) and to determine the influence of central corneal thickness (CCT) in these measurements in the healthy population.Design:A prospective cross-sectional study.Methods:Intraocular pressure (IOP) of the right eyes of 120 patients was measured with GAT and R7. All patients were free of glaucoma. All the measurements were carried out between 7 am and 9 am The measurements with the R7 were taken in the automatic mode. After 15 minutes, IOP with GAT was measured followed by pachymetry. The R7 provided a Goldmann-correlated IOP (IOPg) and a corneal-compensated IOP (IOPcc).Results:The mean age of the patients was 53.919.3 (range, 26 to 85 y). The male/female ratio was 0.9/1. When R7 measurements were compared with GAT measurements, R7 measurements (both IOPcc and IOPg) were significantly higher than GAT measurements (P0.001). Besides that, IOPcc was significantly higher than IOPg (P0.001). There was a significant positive linear relationship between IOPcc and GAT (r=0.761, P0.001), and similar relationship between IOPg and GAT (r(2)=0.739, P0.001). The mean CCT was 545.9 +/- 33.2 m (range, 476 to 634 m). A weak correlation was observed between CCT and GAT (r=0.196, P=0.032). There was a significant correlation between CCT and IOPg (r=0.283, P=0.02). The correlation between CCT and IOPcc was not statistically significant (r=0.123, P=0.179).Conclusions:IOP values of R7 are higher than GAT values. However, IOPg was observed more coherent to the GAT values than IOPcc. IOPcc should be an evaluation factor along with GAT or IOPg in glaucoma examination.