Validity and limits of the rebound tonometer (ICare®): clinical study.

PurposeThe aim of this study was to evaluate the measurement of intraocular pressure (IOP) using a new induction/impact rebound tonometer (ICare®) compared with Goldmann applanation tonometry (GAT). We also aimed to quantify the systematic and random errors (bias) of the 2 methods, to evaluate the sensitivity and specificity of the ICare® tonometer in identifying patients with 21 mmHg or more measured with the GAT, and to study the influence of corneal thickness on IOP measurement with the 2 tonometers.MethodsWe compared the IOP values obtained with the 2 instruments in 97 patients.ResultsAnalysis based on the Bland and Altman method revealed that the IOP values recorded with the ICare® tonometer were slightly higher than those obtained with the GAT. The estimated bias for right eye measurements was 0.78 mmHg with 95% limits of agreement ±3.55 mmHg. This overestimation, which is not clinically relevant, was confirmed when we used the IOP values corrected according to central corneal thickness for data ana...