Accuracy and Reliability of Self-measured Intraocular Pressure in Glaucoma Patients Using the iCare HOME Tonometer.

Abstract

The iCare HOME tonometer is a useful tool which can be used by patients for fairly accurate and reliable self-measurement of intraocular pressure (IOP). The aim was to compare the accuracy of IOP measurements of trained glaucoma patients using the iCare HOME tonometer before and after a week of self-monitoring at home and study the repeatability of patient measurements done at home. A total of 40 glaucoma patients had IOPs measured using the Goldmann applanation tonometer and the iCare HOME. Patients were trained to use the iCare HOME and measured their IOP twice daily over a loan period of 7 days. Bland-Altman analysis was used to assess agreement between Goldmann applanation tonometer and iCare HOME readings. Intraclass correlation coefficient compared inter-rater reliability of iCare HOME measurements, and test-retest variability for the patient's readings over the 7-day period were analyzed. A 5-point Likert scale questionnaire was used to assess the patient's experience with the device. Up to 32 patients (80%) were able to obtain IOP readings within 3 mm Hg of the glaucoma nurse clinician's readings at the preloan visit, and up to 36 patients (90%) at the postloan visit. Good inter-rater reliability was observed between iCare HOME measurements by the glaucoma nurse clinician and patients. At the postloan visit, inter-rater reliability was good for right eye readings and excellent for left eye readings. No distinct trend in test-retest variability was identified over the 7-day period. 65% of patients agreed the device was easy to use and 89% would recommend the device to other glaucoma patients. Patients trained to use the iCare HOME device can do so with fair accuracy compared with trainers with accuracy improving within 1 week of usage.