Comparison of standard versus wide-field composite images of the corneal subbasal layer by In vivo confocal microscopy

Purpose: To evaluate whether the densities of corneal subbasal nerves and epithelial immune dendritiform cells (DCs) are comparable between a set of three representative standard images of in vivo confocal microscopy (IVCM) and the wide-field mapped composite IVCM images. Methods: This prospective, cross-sectional, and masked study included 110 eyes of 58 patients seen in a neurology clinic who underwent laser-scanning IVCM (Heidelberg Retina Tomograph 3) of the central cornea. Densities of subbasal corneal nerves and DCs were compared between the average of three representative standard images and the wide-field mapped composite images, which were reconstructed by automated mapping. Results: There were no statistically significant differences between the average of three representative standard images (0.16 mm(2) each) and the wide-field composite images (1.29 +/- 0.64 mm(2)) in terms of mean subbasal nerve density (17.10 +/- 6.10 vs. 17.17 ± 5.60 mm/mm(2), respectively, P = 0.87) and mean subbasal DC density (53.2 +/- 67.8 vs. 49.0 +/- 54.3 cells/mm(2), respectively, P = 0.43). However, there were notable differences in subbasal nerve and DC densities between these two methods in eyes with very low nerve density or very high DC density. Conclusions: There are no significant differences in the mean subbasal nerve and DC densities between the average values of three representative standard IVCM images and wide-field mapped composite images. Therefore, these standard images can be used in clinical studies to accurately measure cellular structures in the subbasal layer.