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 mm² each) and the wide-field composite images (1.29 ± 0.64 mm²) in terms of mean subbasal nerve density (17.10 ± 6.10 vs. 17.17 ± 5.60 mm/mm², respectively, P = 0.87) and mean subbasal DC density (53.2 ± 67.8 vs. 49.0 ± 54.3 cells/mm², 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.