Easyton® transpalpebral versus Perkins applanation tonometry in different populations

Objective To compare intraocular pressure (IOP) measurements obtained using the new transpalpebral Easyton® tonometer and Perkins applanation tonometer (PAT) in three different clinical populations. Methods The participants of this prospective study were 84 subjects divided into the groups: 22 healthy children (G1), 42 healthy adults (G2), and 20 adult patients with primary open angle glaucoma (G3). The data recorded in 84 eyes of these subjects were age, sex, gender, central corneal thickness (CCT), and axial length (AL). In all eyes, IOP was determined in the same examination room by the same experienced examiner using Easyton® and PAT in random order. Results Mean differences in IOP readings between Easyton® and PAT were 0.45 ± 1.97 ( p = 0.295), − 0.15 ± 2.13 ( p = 0.654), − 1.65 ± 3.22 ( p = 0.033), and − 0.018 ± 2.50 mmHg ( p = 0.500) in the groups G1, G2, G3, and whole sample (G4), respectively. Correlations between Easyton® and PAT IOP values were 0.668 ( p = 0.001) for G1, 0.463 ( p = 0.002) for G2, 0.680 ( p < 0.001) for G3, and 0.605 ( p < 0.001) for G4. Moderate to good agreement between the two tonometers was found in all groups according to intraclass correlation coefficients, which were 0.794 ( p < 0.001) for G1, 0.632 ( p < 0.001) for G2, 0.809 ( p < 0.001) for G3, and 0.740 ( p < 0.001) for G4. The lower and upper limits of agreement between the devices were − 5.1 and 4.7 mmHg, respectively, in the complete group. No correlation was noted between CCT or AL and the Easyton® IOP measurements. Conclusion IOP measurements obtained with Easyton® and PAT show an acceptable level of agreement mainly in healthy individuals, recommending it for IOP screening in children and in patients in which PAT measurement may be impared as patients with hemifacial spasms, corneal irregularities, or reduced mobility. It is not recommended for glaucoma patients follow-up.