Copenhagen 2016 Registration Programme Exhibitor Information Virtual Exhibition Satellite Meetings Glaucoma Day 2016 Hotel Star Alliance

10 - 14 Sept. 2016, Bella Center, Copenhagen, Denmark

This Meeting has been awarded 27 CME credits


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Comparison of IOP measurement by Goldmann applanation tonometer, Icare rebound tonometer and Tono-Pen in keratoconus patients after MyoRing implantation

Poster Details

First Author: M. Rateb EGYPT

Co Author(s):    M. Rateb   M. Abd El-Radi   M. Anwar              

Abstract Details


To evaluate the different IOP readings by Goldmann Applanation Tonometer (GAT), ICare Rebound Tonometer and Tonopen in Keratoconus patients after Myoring implantation. To assess the influence of Central corneal thickness (CCT) and thinnest corneal location (TCL) on IOP measurements by different tonometers.


Prospective observational study was conducted in Tiba eye Center (private practice), Assiut, Egypt from August 2015 till January 2016.


Ten patients suffering from Keratoconus and underwent Myoring implantation were recruited. All subjects underwent GAT, ICare and Tonopen IOP measurements in random order. Central corneal thickness and thinnest corneal location were assessed by Pentacam. Difference in mean in IOP readings were assessed by T-test. Correlation between each pair of devices was evaluated by Pearson Correlation coefficient. The Bland–Altman analysis was used to assess inter-tonometer agreement.


Seventeen eyes (10 patients) were evaluated. The mean IOP reading were 13.9±3.68, 12.41±2.87 and 14.29±1.31 mmHg in GAT, ICare and Tonopen group respectively. There was a significant difference between IOP readings by GAT/ICare and Tonopen/ICare (p-value; 0.032, 0.002 respectively) with no significant difference between GAT/Tonopen (p-value; 0.554). Mean difference in IOP measurements between GAT/ICare was 1.49±2.61 mmHg, Tonopen/ICare was 1.89±2.15 mmHg and GAT/Tonopen was – 0.39±2.59 mmHg. There was no significant correlation between the difference in IOP readings among any pair of devices and CCC or TCL. The Bland-Altman analysis showed a reasonable agreement between any pair of tonometers.


Though ICare tonometer tends to provide underestimated IOP readings than GAT or Tonopen, the agreement between GAT, ICare and Tonopen was clinically acceptable in patients underwent Myoring implantation for management of Keratoconus. IOP difference between any pair of tonometers was not influenced by central corneal thickness or thinnest corneal location.

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