Table 5.
Endothelial cell density (ECD) of heterogeneous corneas (group 2, n=30) by automated analysis method: mono-image (each of the three images is analysed in isolation) or tri-image (the images are analysed simultaneously) for 50 and 300 cells, and comparison with manual count
| Analysis method | No | Mean ECD (SD, range) Cells/mm2 | Mean ECD discrepancy with manual count (cells/mm2, p) | Pearson's r* |
| Mono 50 (image 1) | 30 | 2139 (581, 921–3134) | 66 (p=0.35) | 0.76 |
| Mono 50 (image 2) | 30 | 2220 (455, 1464–3184) | 147 (p=0.064) | 0.54 |
| Mono 50 (image 3) | 30 | 2273 (633, 937–3754) | 200 (p=0.007) | 0.82 |
| Mono 300 (image 1) | 26† | 2265 (452, 1259–2923) | 155 (p=0.007) | 0.81 |
| Mono 300 (image 2) | 28† | 2296 (514, 1555–3484) | 229 (p=0.009) | 0.59 |
| Mono 300 (image 3) | 25† | 2241 (526, 933–3246) | 183 (p=0.012) | 0.77 |
| Tri image 50 | 30 | 2159 (442, 1410–2932) | 86 (p=0.019) | 0.91 |
| Tri image 300 | 30 | 2204 (412, 1545–2994) | 131 (p=0.001) | 0.94 |
| Manual count | – | 2073 (420, 1248–3094) | – | – |
†Missing data: 300 cells uncountable due to adequate or medium image quality. ‡As with the group 1 corneas, the manual count underestimated ECD by a mean 7.1% (mean: 148 cells/mm2, range 66–229) in comparison with the automated analyses. The best correlations with manual analysis were obtained in tri-image mode with a 300 cells count (r = 0.94), then in tri-image 50 mode (r = 0.91). However, the correlations were weaker in mono-image mode and even poor in some modes (r = 0.54 and r = 0.59).
ECD = endothelial cell density, SD = standard deviation, Mono 50 = analysis of one image and 50 cells, Mono 300 = analysis of one image and 300 cells, tri-image 50 = analysis of three images simultaneously and 50 cells, tri-image 300 = analysis of three images simultaneously and 300 cells.
*all p values <0.001.