Reliability of Self-monitoring of Intraocular Pressure with iCare Home2 Rebound Tonometry.

Abstract

Prcis: Using iCare Home2 (iCare, Finland) rebound tonometry, self-measurement of intraocular pressure has demonstrated good reliability and ease of use.

Purpose: To investigate reliability and repeatability of self-measured intraocular pressure (IOP) with rebound tonometry using iCare Home2.

Patients and methods: 104 patients out of 110 consecutive patients were recruited for this observational cross-sectional study. One randomly selected eye from each patient underwent six consecutive IOP measurements with Goldmann applanation tonometry (GAT), iCare IC200 and iCare Home2. Every eye was tested twice with each device, in random order, by an ophthalmologist for GAT and IC200, and by the patient itself for Home2. In addition, central corneal thickness (CCT) has been collected. Reliability of Home2 has been tested calculating Limits of Agreement (LoA) between self-measured and physician-measured IOP, using the Bland-Altman analysis. Repeatability of each device has been tested calculating Limits of Repeatability (LoR) with the same method. Pearson correlation coefficient was used to determine the correlation between differences in IOP measurements and CCT.

Results: The mean difference between GAT and iCare Home2 was -0.28±1.57 mm Hg (P=0.070), 95%-LoA: [-3.36, 2,79 mm Hg]. The mean difference between IC200 and iCare Home2 was 0.92±1.48 mm Hg (P<0.0001), 95%-LoA [-1.98, 3.82 mm Hg]. The mean difference between the first and second measurement with GAT, iCare IC200, and iCare Home2 measurements was 0.21±0.98 mm Hg (P=0.03), -0.02±1.11 mm Hg (P=0.88) and -0.23±1.04 mm Hg (P=0.05).

Conclusions: Self-measured IOP with rebound tonometry showed good reliability and repeatability when compared with physician-measured IOP with both standard GAT and rebound tonometry.