TY - JOUR
T1 - Overestimation of corneal endothelial cell density in smaller frame sizes in In Vivo confocal microscopy
AU - Kheirkhah, Ahmad
AU - Saboo, Ujwala S.
AU - Marmalidou, Anna
AU - Dana, Reza
PY - 2016/1/1
Y1 - 2016/1/1
N2 - Purpose: To evaluate the effect of frame size on the calculated corneal endothelial cell density (CECD) in images of laser scanning in vivo confocal microscopy (IVCM). Methods: Forty-nine corneal endothelial images acquired by laser scanning 1VCM (Heidelberg Retina Tomograph 3 with Rostock Corneal Module) with different endothelial cell densities were analyzed. In each image (160,000 μm2), die CECD was calculated using the fixed-frame method by counting cells in the following frame sizes: 80,000 μm2, 40,000 μm2, 20,000 μm2, 10,000 μm2, 5000 μm2, and 2500 μm2. The calculated CECD was then compared with that of the variable-frame method as the reference value. Results: There was no significant difference in die calculated CECD between the variable-frame method (2004 ± 832 cells/mm2), and the fixed-frame method using a 40,000-μm2 frame (2023 ±810 cells/mm2). On the other hand, the calculated CECD showed significant overestimations in frame sizes of 20,000 jinr (2066 ± 820 cells/mm2), 10,000 μm2 (2156 ± 785 cells/mm2), 5000 \μm2 (2352 ± 783 cells/mm2), and 2500 \μm2 (2715 ± 754 cells/mm2), with P < 0.001 in all. This resulted in overestimations of 4.8 ± 9.8%, 11.9 ± 16.2%, 24.9 ± 23.1%, and 49.1 ± 38.8% for these frame sizes, respectively. Images with lower CECD demonstrated higher overestimations of cell density in smaller frame sizes. Conclusions: In laser scanning IVC'M images, there is significant overestimation of CECD if the celLs are counted in frames smaller than 25% of the image. Similar frame sizes should be used when monitoring CECD over time.
AB - Purpose: To evaluate the effect of frame size on the calculated corneal endothelial cell density (CECD) in images of laser scanning in vivo confocal microscopy (IVCM). Methods: Forty-nine corneal endothelial images acquired by laser scanning 1VCM (Heidelberg Retina Tomograph 3 with Rostock Corneal Module) with different endothelial cell densities were analyzed. In each image (160,000 μm2), die CECD was calculated using the fixed-frame method by counting cells in the following frame sizes: 80,000 μm2, 40,000 μm2, 20,000 μm2, 10,000 μm2, 5000 μm2, and 2500 μm2. The calculated CECD was then compared with that of the variable-frame method as the reference value. Results: There was no significant difference in die calculated CECD between the variable-frame method (2004 ± 832 cells/mm2), and the fixed-frame method using a 40,000-μm2 frame (2023 ±810 cells/mm2). On the other hand, the calculated CECD showed significant overestimations in frame sizes of 20,000 jinr (2066 ± 820 cells/mm2), 10,000 μm2 (2156 ± 785 cells/mm2), 5000 \μm2 (2352 ± 783 cells/mm2), and 2500 \μm2 (2715 ± 754 cells/mm2), with P < 0.001 in all. This resulted in overestimations of 4.8 ± 9.8%, 11.9 ± 16.2%, 24.9 ± 23.1%, and 49.1 ± 38.8% for these frame sizes, respectively. Images with lower CECD demonstrated higher overestimations of cell density in smaller frame sizes. Conclusions: In laser scanning IVC'M images, there is significant overestimation of CECD if the celLs are counted in frames smaller than 25% of the image. Similar frame sizes should be used when monitoring CECD over time.
KW - Cornea
KW - Endothelial cells
KW - In vivo confocal microscopy
UR - http://www.scopus.com/inward/record.url?scp=84959155797&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84959155797&partnerID=8YFLogxK
U2 - 10.1097/ICO.0000000000000698
DO - 10.1097/ICO.0000000000000698
M3 - Article
C2 - 26606299
AN - SCOPUS:84959155797
VL - 35
SP - 363
EP - 369
JO - Cornea
JF - Cornea
SN - 0277-3740
IS - 3
ER -