@article {603916,
	title = {Overestimation of Corneal Endothelial Cell Density in Smaller Frame Sizes in In Vivo Confocal Microscopy.},
	journal = {Cornea},
	volume = {35},
	number = {3},
	year = {2016},
	month = {2016 Mar},
	pages = {363-9},
	abstract = {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 IVCM (Heidelberg Retina Tomograph 3 with Rostock Corneal Module) with different endothelial cell densities were analyzed. In each image (160,000 μm), the CECD was calculated using the fixed-frame method by counting cells in the following frame sizes: 80,000 μm, 40,000 μm, 20,000 μm, 10,000 μm, 5000 μm, and 2500 μm. The calculated CECD was then compared with that of the variable-frame method as the reference value. RESULTS: There was no significant difference in the calculated CECD between the variable-frame method (2004 {\textpm} 832 cells/mm), and the fixed-frame method using a 40,000-μm frame (2023 {\textpm} 810 cells/mm). On the other hand, the calculated CECD showed significant overestimations in frame sizes of 20,000 μm (2066 {\textpm} 820 cells/mm), 10,000 μm (2156 {\textpm} 785 cells/mm), 5000 μm (2352 {\textpm} 783 cells/mm), and 2500 μm (2715 {\textpm} 754 cells/mm), with P \&lt; 0.001 in all. This resulted in overestimations of 4.8 {\textpm} 9.8\%, 11.9 {\textpm} 16.2\%, 24.9 {\textpm} 23.1\%, and 49.1 {\textpm} 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 IVCM 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.},
	issn = {1536-4798},
	doi = {10.1097/ICO.0000000000000698},
	author = {Kheirkhah, Ahmad and Saboo, Ujwala S and Marmalidou, Anna and Dana, Reza}
}
