Comparison Of Intraocular Pressure Measurements Using 3 Different Methods (Goldman Applanation Tonometry (Gat), Corvis St And Icare) Following Penetrating Keratoplasty

To compare Intraocular Pressure (IOP) readings using 3 different methods (Goldman Applanation Tonometry (GAT), Corvis ST and iCare) in patients that have underwent Penetrating Keratoplasty (PKP).

Observational, cross-sectional study with prospective recruitment of patients involving patients that underwent PKP in a tertiary hospital in Greece. 

Patients were examined after the first postoperative month. The examination included Corrected Distance Visual Acuity (CDVA), IOP measurement using GAT, Corvis (including both uncorrected IOP (CVS-IOP) and biomechanical IOP(bIOP)) and iCare, slit lamp examination and measurement of Central Corneal Thickness (CCT) using Corvis ST. Primary outcome of the study was the IOP readings using GAT, Corvis ST and iCare and the correlation between the latter and GAT-IOP whereas the secondary outcomes included the correlation between CCT and IOP readings using the three different methods.

10 eyes of 10 patients were examined following PKP in our centre with a mean ageof 68,4 ± 10,7 years. Icare IOP, CVS-IOP and bIOP were all found to be lower than GAT-IOP (mean  18,6 ± 8,4 SD mm Hg) but not statistically different than GAT-IOP (p= 0,167,  p= 0,4928, p= 0,0530 respectively. Mean CCT in our cohort was 498,5 ± 81 μm. When running the pearson’s coefficient test we found that there is no significant linear relationship between any of them and CCT.

In our study  we found good agreement between GAT-IOP, which is considered the gold standard until today amongst post-PKP patients, and iCare-IOP, CVS-IOP and bIOP rendering all the above options suitable alternatives for the post-PKP IOP monitoring.