Measurements of central corneal thickness and endothelial parameters with three different non-contact specular microscopy devices.

We aimed to compare the measurements of central corneal thickness (CCT) and endothelial parameters with three different non-contact specular microscopy (SM) devices. Fifteen eyes of 15 healthy individuals (6 males; 9 females) were enrolled in the study. Mean age was 37.93 ± 15.13 years. Endothelial parameters and CCT were measured with Nidek CEM-530, Topcon SP-3000P, and Tomey EM-3000 SM devices by the same physician. Endothelial parameters included endothelial cell count (ECC), maximum, minimum, and average endothelial cell size. and hexagonality ratio. There were no statistically significant differences in ECC, CTT, and average endothelial size (AES) between the devices (p > 0.05). The measurement of maximum endothelial size (MES) was different between Nidek SM and Topcon SM devices (p = 0.001), but there was no difference in MES between Nidek SM and Tomey SM (p = 0.058), and between Topcon SM and Tomey SM (p = 0.081). There was no difference in minimum endothelial size (MinES) between Nidek SM and Topcon SM (p = 0.794); however, there was a significant difference in MinES between Tomey SM and Nidek SM (p < 0.001), and between Tomey SM and Topcon SM (p < 0.001). Comparison of hexagonality ratio showed statistically significant difference between the devices (p < 0.001). No significant differences in the measurements of ECC, CCT, and AES were detected between different SM devices, whereas a statistically significant difference in hexagonality ratio was detected between the devices. These devices should not be used alternatively in the endothelial morphology assessment in patient's follow-up.