Comparison of Intraocular Pressure Measurements With Goldmann Applanation Tonometry, Tonopen XL, and Pascal Dynamic Contour Tonometry in Patients With Descemet Membrane Endothelial Keratoplasty

Abstract

Précis: IOP measured with Tonopen and DCT was higher than GAT in eyes that underwent DMEK. Purpose/Aim of the study: To compare intraocular pressure (IOP) measurements measured based on Goldmann applanation tonometry (GAT), Tonopen XL, and Pascal Dynamic Contour Tonometry (DCT) in patients who had undergone descemet membrane endothelial keratoplasty (DMEK) and to appraise the influence of central corneal thickness (CCT) on IOP measurements. Materials and Methods: Thirty-four eyes (from 34 patients) who underwent DMEK at least 1 month before the study were included. We performed Tonopen XL, GAT, and DCT IOP measurements at 10 min intervals. Bland-Altman plots were used to assess agreement between GAT, Tonopen XL, and DCT. Spearman rank correlation was used to calculate the deviation from GAT readings by each device and correlate the readings with the CCT variable. Results: The mean IOP values with GAT, Tonopen XL, and DCT were 14.9±5.8, 16.2±5.5, and 19.2±5.0, respectively. Statistically significant differences between GAT and Tonopen XL and between GAT and DCT were noted (r=0.942 [0.885–0.971]; P=0.0001 and r=0.942 [0.885–0.971]; P=0.0001, respectively). DCT tended to return a higher IOP relative to GAT and Tonopen XL. CCT and IOP readings obtained by GAT, Tonopen XL, and DCT did not show a statistically significant correlation with each other. Conclusion: IOP as measured with both Tonopen and DCT was found to be higher than GAT in eyes that underwent DMEK surgery although the techniques showed a good correlation. After DMEK surgery, all 3 measurement techniques can be practical in routine postoperative examinations, however it is recommended to measure IOP with the same device during patient follow-up.