The Tonopen and DCT measurements of IOP were greater than the GAT readings in DMEK eyes. Goal: to evaluate the effect of central corneal thickness (CCT) on intraocular pressure (IOP) readings by comparing readings obtained with Goldmann applanation tonometry (GAT), Tonopen XL, and Pascal Dynamic Contour Tonometry (DCT) in patients who had undergone descemet membrane endothelial keratoplasty (DMEK). 

There were 34 eyes included in the trial, all of which had DMEK at least 1 month before enrollment. Researchers took IOP readings every 10 minutes using Tonopen XL, GAT, and DCT. They compared the degree of agreement between the GAT, Tonopen XL, and DCT using Bland-Altman plots. To determine the degree to which each device deviates from the GAT and to establish a correlation between the devices and the CCT variable, they employed Spearman rank correlation. The average intraocular pressure (IOP) with GAT was 14.9±5.8; with Tonopen XL, it was 16.2±5.5; and with DCT, it was 19.2±5.0. There were statistically significant differences between GAT and Tonopen XL (r=0.942 [0.885-0.971]; P=0.0001) and GAT and DCT (r=0.942 [0.885-0.971]; P=0.0001). DCT typically gave a better IOP than GAT and Tonopen XL. 

There was no statistically significant relationship between the CCT and IOP readings from the GAT, Tonopen XL, and DCT. Although there was a strong correlation between the methods, it was observed that Tonopen and DCT measured IOP to be greater than GAT in eyes that had undergone DMEK surgery. All 3 methods are applicable in normal postoperative examinations after DMEK surgery; nevertheless, it is advised that IOP be measured using the same device throughout patient follow-up.

Source: journals.lww.com/glaucomajournal/Fulltext/2022/11000/Comparison_of_Intraocular_Pressure_Measurements.10.aspx