Comparation of the new rebound tonometer IOPen and the Goldmann tonometer, and their relationship to corneal properties

Abstract

Purpose To compare the intraocular pressures (IOPs) obtained with the IOPen rebound tonometer, Goldmann applanation tonometer (GAT) and the ocular response analyzer (ORA) and investigate the effects of corneal biomechanical properties on IOPen measurements. Methods A total of 198 normal eyes were included in this cross-sectional and randomized study. Three measurements were taken using IOPen. Agreement between tonometers was calculated using the Bland and Altman limits of agreement (LoA) analysis. Results The median IOPen IOP was 3 mm Hg below the GAT (Po0.001), 3 mm Hg below the ORA IOP similar to Goldmann (IOPg), and 3 mm Hg below the ORA IOP corrected using corneal parameters (IOPcc)(Po0.01). The LoA width between the IOPen and GAT IOPs varied between 13.92 (mean IOPen IOP) and 15.99 mm Hg (third IOPen measurement). The central corneal thickness (CCT) was unrelated to IOPen measurements (P40.05). Corneal hysteresis (CH) and corneal rigidity factor (CRF) were correlated with IOPen and GAT. Conclusions IOPen underestimated the IOP compared with GAT and ORA. The effect of measurement quality or measurement order on IOPen was low. CCT did not affect the IOPen, but the CH and CRF did. The LoA width between the IOPen and GAT IOPs was higher than between the ORA IOPg or ORA IOPcc and GAT IOPs.

The Icare-Pro Rebound Tonometer Versus the Hand-held Applanation Tonometer in Congenital Glaucoma

“…[16][17][18] However, it is worthwhile mentioning the recent reports made by Rosentreter and colleagues, 19,20 who claim that the conventional Icare tonometer underestimates significant IOP comparing to GAT, in patients with a corneal abnormality such as those who have undergone keratoplasty, as rebound tonometry may be extremely affected by corneal properties. 21,22 There is scarce information in the relevant literature regarding the correlation existing between rebound and Perkins when used in pediatric patients. In this subset of patients, Martı´nez-de-la-Casa et al 2 detected good correlation using the conventional Icare in children aged 3 to 13 who were cooperative enough to avoid general anesthesia (r = 0.869, P < 0.001).…”

Central corneal thickness does not correlate with TonoLab-measured IOP in several mouse strains with single transgenic mutations of matricellular proteins

“…In the future, it may be important to study the effects of other corneal properties, such as curvature, elasticity, and rigidity on RT-based mouse IOP measurements (Moreno-Montanes et al, 2011), as these properties are not reflected in simple CCT measurement (Munger et al, 2001) and may also have an impact on probe head deceleration times. Additionally, studying mice at older ages may be needed as some have reported that CCT may not be fully matured until 7–8 weeks for C57BL/6 mice (Burns et al, 2011).…”

Comparison of intraocular pressure measurement between rebound, non‐contact and Goldmann applanation tonometry in treated glaucoma patients

“…Numerous recent studies have compared RT with GAT 11,12 . Most have utilized the RT manufactured by iCare (iCare, Helsinki, Finland).…”

“…In a study of 198 normal eyes, Moreno‐Montanes et al 11 . reported on another type of RT, the IOPen (Medicel, Wolfhalden, Switzerland).…”

“…A number of studies have compared NCT using the ORA (Reichert, Buffalo, USA) versus GAT in normal and glaucoma patients 11,18–20 . Three studies found IOPcc tended to overestimate GAT 18–20 ranging from 1.56 to 2.67 mmHg.…”