Comparison of semi-automated center-dot and fully automated endothelial cell analyses from specular microscopy images

To evaluate two specular microscopy analysis methods across different endothelial cell densities (ECDs).

Endothelial images of one eye from each of 45 patients were taken by using three different specular microscopes (three replicates each). To determine the consistency of the center-dot method, we compared SP-6000 and SP-2000P images. CME-530 and SP-6000 images were compared to assess the consistency of the fully automated method. The SP-6000 images from the two methods were compared. Intraclass correlation coefficients (ICCs) for the three measurements were calculated, and parametric multiple comparisons tests and Bland-Altman analysis were performed.

The ECD mean value was 2425 ± 883 (range 516-3707) cells/mm². ICC values were > 0.9 for all three microscopes for ECD, but the coefficients of variation (CVs) were 0.3-0.6. For ECD measurements, Bland-Altman analysis revealed that the mean difference was 42 cells/mm² between the SP-2000P and SP-6000 for the center-dot method; 57 cells/mm² between the SP-6000 measurements from both methods; and -5 cells/mm² between the SP-6000 and CME-530 for the fully automated method (95% limits of agreement: - 201 to 284 cell/mm², - 410 to 522 cells/mm², and - 327 to 318 cells/mm², respectively). For CV measurements, the mean differences were - 3, - 12, and 13% (95% limits of agreement - 18 to 11, - 26 to 2, and - 5 to 32%, respectively).

Despite using three replicate measurements, the precision of the center-dot method with the SP-2000P and SP-6000 software was only ± 10% for ECD data and was even worse for the fully automated method.

Japan Clinical Trials Register ( http://www.umin.ac.jp/ctr/index/htm9 ) number UMIN 000015236.