Abstract
Purpose: :
The objective of this in vivo study was to establish the distribution of the corneal nerve fibers in the sub–basal plexus in humans.
Methods: :
Nerve fiber patterns up to 4x4 mm in size of the sub–basal plexus in 20 eyes of 10 healthy volunteers (age range between 22 and 40 years) were recorded using In vivo confocal laser scanning microscopy. The microscopy was performed using a Rostock Cornea Module attached to an Heidelberg Retina Tomograph II (Heidelberg Engineering, Germany) extended with an electro–mechanically driven xyz–stage. Two–dimensional mapping (slice alignement, intensity adjustment, resampling) was performed using AMIRA (TGS Inc., USA) and Stitcher (RealVIZ S.A., USA). Additionally, at selected locations, 3D scanning and volume reconstruction was performed to obtain depth related information. The distribution of the nerve fibers was described qualitatively.
Results: :
Superpositioning of images indicated a consistent appearance in all investigated corneae. Nerve fibers coplanar to Bowman’s layer originating peripherally run radial inward towards an area located at the lower nasal quadrant. Within this area a plexus of curved nerves with a clockwise whirl–shaped pattern can be seen. Hidden under this area inside the stroma a normal looking keratocytes network without nerval conglomerations can be observed.
Conclusions: :
Contrary to the established and accepted anatomical description human sub–basal nerve fibers have a consistent appearance with a whirl–shaped region located at the lower nasal quadrant. This observation could have an important relevance concerning incision during and re–innervation after corneal surgery.
Keywords: cornea: basic science • nerve fiber layer • microscopy: confocal/tunneling