Mapping of the Normal Human Corneal Sub-Basal Nerve Plexus by In Vivo Laser Scanning Confocal Microscopy

Abstract

This is the first study to elucidate the overall distribution of sub-basal nerves in the healthy, live central to mid-peripheral human cornea by laser scanning in vivo confocal microscopy. The whorl pattern of the sub-basal nerves is similar to that seen in the epithelium in corneal verticillata and may lend support to the theory that epithelial cells and nerves migrate centripetally in tandem.

Corneal sensitivity and morphology of the corneal subbasal nerve plexus in primary congenital glaucoma

“…8,9 Recent studies analyzed the morphology of the subbasal nerve plexus in normal corneas by confocal microscopy. [10][11][12] Moreover, the architecture of the corneal subbasal nerve plexus has been investigated, with the aid of confocal microscopy, in patients with keratoconus, Sjogren syndrome, or dry eye, as well as after penetrating keratoplasty, laser in situ keratomileusis, or photorefractive keratectomy. [13][14][15][16][17][18][19][20][21] Within this context, the purpose of this study was to investigate the corneal sensitivity in patients with PCG and correlate the clinical findings with the corneal subbasal nerve density by use of LSCM.…”

Surgical outcomes of phototherapeutic keratectomy on Epithelial basement membrane dystrophy, and the characterisation of Bowman's Layer

“…Nerves in the image are then semi-automatically traced by the aid of tracing software [43,108] to determine total nerve length, which is then divided by the area in the field of view, to determine nerve density in μm/mm 2 . The subbasal nerve density in humans changes with age [26], but in general the accepted value for the average subbasal nerve density by IVCM is about 20 000 μm/mm 2 in the central cornea [25,26,45].…”

“…These stromal nerve fibers branch anteriorly from the middle third of the stroma, forming a subepithelial plexus under Bowman´s layer. The nerves then penetrate Bowman´s layer losing the Schwann cells, and forming a subbasal plexus that gives rise to the naked terminal endings at the at the superficial epithelial cell level [25][26][27][28][29][30].…”

“…Quantitative nerve analysis has been performed by a number of investigators [25,43,45,46] and in the case of the subbasal nerve plexus, reporting of nerve density has followed an accepted convention. Nerve density values determined from laser scanning confocal instruments can therefore be compared.…”

The power of observation

“…We went on to demonstrate the formation of whorls by cultured corneal epithelial cells under the influence of magnetic fields (9) . Latterly we and others (10,11) have demonstrated that the sub-basal plexus of corneal nerves too have a whorl configuration and relates to the whorl pattern of the epithelial cells. There is more going on than meets the eye!…”