Intraocular Pressure Measurements Following Descemet Stripping Endothelial Keratoplasty

Purpose

The effect of increased corneal thickness after Descemet stripping endothelial keratoplasty (DSEK) on intraocular pressure (IOP) measurement has not been previously studied. It is uncertain if this increase in corneal thickness would artificially elevate IOP reading by Goldmann tonometry [GAT] (Haag-Streit, Konig, Switzerland). Therefore the effect of DSEK-related thick cornea on IOP measurement was investigated using three different techniques.

Design

Prospective cross-sectional study.

Methods

Participants were recruited from a single tertiary referral center. Fifty eyes of 38 patients with successful DSEK at least three months prior to testing were evaluated. At the time of the study, none of the participants had clinically detectable corneal edema. IOP was measured with GAT, pneumatonometry, and dynamic contour tonometry (DCT) in an unmasked randomized sequence. Central corneal thickness (CCT) was measured by ultrasonic pachymetry.

Results

Mean CCT was 701 ± 68 μm. The mean IOP ± standard deviation (SD) was 15.9 ± 4.9 mm Hg for GAT, 20.3 ± 4.5 mm Hg for pneumatonometry, and 19.8 ± 4.4 mm Hg for DCT. Pneumatonometry and DCT IOP measurements were significant higher than GAT (P < .01). In contrast, the difference between pneumatonometry and DCT readings was not statistically significant (P = .28). The correlations between IOP and corneal thickness were not significant in this cohort (P > .05).

Conclusions

Falsely elevated GAT, as expected in thick corneas, was not demonstrated after DSEK. High IOP reading by GAT therefore should raise suspicion of elevated IOP in DSEK eyes.