Agreement of Serial iCare HOME2 and Goldmann Applanation Tonometry.

ABSTRACT

PURPOSE: To assess agreement of iCare HOME2 and Goldmann applanation tonometry over a wide range of intraocular pressure (IOP). DESIGN: A prospective, observational cohort study. SUBJECTS: Twenty-six adult patients undergoing intravitreal injection, which temporarily raises IOP, were recruited from the Palo Alto Medical Foundation Retina Clinic between October 2022 and February 2023. METHODS: Subjects had serial iCare HOME2 (IOPI) and Goldmann applanation (IOPG) IOP measurements before and at 0 and 5 to 10 minutes after injection. Baseline IOPs and pachymetry were taken in both eyes. MAIN OUTCOME MEASURES: Correlation between IOPI and IOPG was tested by within-subjects intraclass correlation coefficient (ICC) for repeated measures. Agreement between IOPI and IOPG was evaluated by a Bland-Altman plot with correction for multiple measurements. The difference between IOPI and IOPG was evaluated between eyes at baseline (Pearson's r) and within the injected eye over different timepoints (ICC for absolute agreement). Linear regression was used to evaluate the effects of age, sex, glaucoma, and corneal thickness. RESULTS: The mean IOPI and IOPG were 25.3 (range 9-55) and 23.5 (range 8-56) mmHg, respectively. The correlation between IOPI and IOPG was 0.99 (P < 0.001). The mean difference (IOPG - IOPI) was 2.2 mmHg (95% limits of agreement -3.4 to 7.8 mmHg). The bias in measurements was correlated between eyes (r, 0.68; P < 0.001) and in the injected eye across all timepoints (ICC, 0.86; 95% CI, 0.75-0.93), but did not show a relationship with age, sex, glaucoma, or corneal thickness. CONCLUSIONS: IOPI and IOPG showed excellent correlation; however, there was a stable bias toward IOPG being higher than IOPI over a large range of IOP. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.