Agreement of corneal endothelial cell analysis between konan-noncon robo sp-6000 and tomey em-3000 specular microscopes in healthy subjects

Doha Jbara, Asaf Achiron, Gal Antman, Ortal Buhbut, Idan Hecht, Raimo Tuuminen, Irit Bahar, Uri Elbaz

Research output: Contribution to journalArticlepeer-review


Purpose: To compare corneal endothelium parameters taken by two common noncontact specular microscopes in healthy subjects. Methods: Healthy participants visiting the outpatient eye clinic at the Rabin Medical Center, Petah Tikva, Israel, were recruited prospectively. All participants underwent three consecutive corneal endothelial cell photographs with both the Konan-Noncon Robo SP-6000 and the Tomey EM-3000 specular microscopes. Endothelial cell density (ECD) was evaluated using the manual center technique in both machines. Bland-Altman graphs were used to assess the agreement between the devices, and intraclass correlation coefficient (ICC) served to assess intraobserver variability for each device. Results: Recruited were 49 healthy subjects with a mean age of 48.9615.6 years, 49 right eyes were included. The mean ECD was comparable between the Tomey EM-3000 and the Konan-Noncon Robo SP-6000 (2,713.26242.4 vs. 2,700.86300.5 cells/mm2, respectively, P=0.47) with a mean difference of 12.4 cells/mm2 (0.67%), a mean ECD absolute difference of 93.3 cells/mm2, and low 95% limits of agreement of 2222.0 to +246.9 cells/mm2. A folded empirical distribution function curve showed that all differences fell within 525.4 cells/mm2, centered around a median of 13.3 cells/mm2. Intraclass correlation coefficient was high for both the Konan-Noncon Robo SP-6000 (0.93, 95% confidence interval [CI]: 0.89-0.95) and the Tomey EM-3000 (0.88, 95% CI: 0.82-0.93). Conclusions: The difference in endothelial cell measurements between the Konan SP-6000 and the Tomey EM-3000 specular microscopes through the center and the L-count analyzing techniques, respectively, is clinically small and not statistically significant. Nevertheless, caution should be taken when used interchangeably because ECD difference between the two machines can be as high as 525.4 cells/mm2.

Original languageEnglish
Pages (from-to)191-195
Number of pages5
JournalEye and Contact Lens
Issue number4
StatePublished - 1 Apr 2021


  • Endothelial cell count
  • Konan-Noncon Robo SP-6000
  • Specular microscopy
  • Tomey EM- 3000


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