Interocular Comparison by In Vivo Confocal Microscopy of the 2-Dimensional Architecture of the Normal Human Corneal Subbasal Nerve Plexus

Abstract

To investigate the configuration of the living human corneal subbasal nerve plexus in paired eyes of normal subjects using in vivo confocal microscopy. Laser scanning in vivo confocal microscopy was performed on both corneas of healthy human subjects, and a grid fixation pattern facilitated examination of consistent areas of central to midperipheral cornea. Macromedia/Adobe Freehand 10 was used to manually arrange images into contiguous montages. The subbasal nerve density and overall patterns were analyzed. Both eyes of 6 subjects (3 women and 3 men, aged between 25 and 36 years) were examined. In all subjects, the subbasal nerve plexus exhibited a clockwise whorl configuration inferior to the central cornea. The mean subbasal nerve density at the whorl was 39.17±4.95 mm/mm and 41.36±4.19 mm/mm in the right and left eyes, respectively. There was no significant difference in the nerve density between the eyes (P=0.61). Bland and Altman analysis confirmed high intraobserver repeatability and moderate interobserver repeatability. This study reveals the marked similarities between the corneal subbasal nerve plexus configuration in the right and left eyes of the living human cornea, highlighting that the typical mirror-image symmetry in corneal topographic patterns is not obeyed in respect to corneal innervation and that a clockwise orientation of the subbasal plexus is typically encountered. There was no statistical difference in the subbasal nerve density between the eyes.