[Influence of corneal thickness in keratoconic corneas on IOP measurement with IOPen, iCare, dynamic contour tonometry and Goldmann applanation tonometry].

BACKGROUND

The aim of this study was to evaluate the effect of central corneal thickness (CCT) of keratoconic corneas on intraocular pressure (IOP) measurements as measured by four different techniques.

PATIENTS AND

METHODS

Forty-one eyes of forty-one keratoconus patients (group 1) and fifty eyes of fifty healthy subjects (group 2) were enrolled. IOP was measured with iCare, IOPen, Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT). CCT was measured by ultrasonic pachymetry. These data were used for statistical analysis.

RESULTS

The mean IOPs measured by GAT, DCT, iCare and IOPen were 11.4, 14.7, 10.8, and 15.7 mmHg in group 1; and 14.2, 15.4, 15.4 and 14.3 mmHg in group 2, respectively. Between both groups, there was a statistically significant difference in iCare (p < 0.001), GAT (p < 0.001) and IOPen (p = 0.040) measurements; with no difference between DCT (p = 0.266) measurements. IOPen measurements were significantly associated with CCT (r = - 0.314; p = 0.046).

CONCLUSION

IOPen seemed to be affected by CCT. IOP readings by iCare, GAT and DCT were found to be independent of CCT in keratoconic corneas.