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

Abstract

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.

Two-year results after combined phacoemulsification and iris-fixated phakic intraocular lens removal

“…Our results yielded an acceptable ECD loss due to surgical trauma, but some cases show unreal gains (and drops) in ECD as the result of measurement error. The reliability of EC analysis is a well-discussed topic [26][27][28][29] with count errors of up to 9% with the SP2000P [29]. In addition, in our study, both the Topcon SP-2000P as the SP-3000P specular microscope was used during follow-up.…”

Measurement of corneal thickness using Pentacam HR versus Nidek CEM-530 specular microscopy

“…The correct explanation could be that the Nidek SM device tends to give thicker CT measurements than other SM devices. In fact, Cakici et al 24 found that the mean CT value provided by the Nidek SM was thicker than that provided by the Tomey SM (Nagoya, Japan) and Topcon SM devices.…”

“…We compared the Oculus Pentacam HR and the Nidek CEM-530 SM because these two devices do not require corneal contact and because both the Pentacam 11,15,[18][19][20][21][22] and Nidek 23,24 have been singularly compared with other devices. Among these comparisons, only a few have involved a Scheimpflug camera versus SM devices 15,[18][19][20] and only one has involved a Scheimpflug camera versus the Nidek CEM-530.…”

<p>Improved Interchangeability with Different Corneal Specular Microscopes for Quantitative Endothelial Cell Analysis</p>

“…Various authors describe that different types of CSMs, manufactured by different companies, are not interchangeable. [3][4][5][6][7][8]16 During our clinical practice and research, we also encountered an interchangeability problem when using different CSMs. In our research involving longitudinal ECC analysis after Artisan IF-pIOLs, we discovered a significant difference in ECCs when we replaced our "old" SP-2000P CMS with the newer SP-3000P version; see Figure 7.…”

“…Different CSMs and image analysis methods have been evaluated for comparability and are usually not interchangeable. [3][4][5][6][7][8] To be able to reliably compare longitudinal ECC measurements, it is therefore wise to use the same CSM and analysis system for all measurements. However, when instruments wear out, it is often no longer possible or even desirable to replace it with the same previous type.…”