Meta-analysis of the concordance of Icare^® PRO-based rebound and Goldmann applanation tonometry in glaucoma patients

The Icare^® PRO rebound tonometer is being promoted as a patient-friendly device for glaucoma detection and monitoring, allowing rapid and accurate intraocular pressure measurement avoiding anaesthesia. The aim of this systematic review was to examine the concordance of Icare^® PRO and Goldmann applanation tonometry in glaucoma patients.

The German and English literature research was carried out using PubMed and Cochrane Library between January 2010 and March 2018. Method comparison trials in a paired sample study design were identified. Search criteria were 'Icare PRO', 'Rebound', 'Goldmann' and 'Applanation'. Adult patients with glaucoma of any aetiology were included. The intraindividual intraocular pressure deviation between Icare^® PRO and Goldmann applanation tonometry (mm Hg) served as primary endpoint, parameterized by the reported mean differences. For each study, an asymptotic 95% confidence interval was derived. The overall intraocular pressure meta-difference (Icare^® PRO-Goldmann applanation tonometry) and 95% confidence interval were estimated using the random effect model.

Of 147 publications, 6 studies (672 eyes) were included after reviewing. Four studies showed an intraocular pressure underestimation by the Icare^® PRO, two an overestimation. The meta-difference (Icare^® PRO-Goldmann applanation tonometry = -0.14 mm Hg; 95% confidence interval: (-0.43 mm Hg; 0.15 mm Hg)) indicated a non-significant, clinically irrelevant mean deviation (p = 0.335). The devices showed good agreement, but there was a strong heterogeneity between the studies (I² = 77%): two studies presented a significant difference (Icare^® PRO-Goldmann applanation tonometry), however, with deviations in opposite directions.

Although the manufacturer advertises the Icare^® PRO as a 'tonometer with superior accuracy', the present review could neither confirm nor deny considerable agreement between Goldmann applanation tonometry and Icare^® PRO in glaucomatous patients.