Ex vivo confocal microscopy of human corneal nerves.
OBJECTIVE
To evaluate the distribution, morphometry and the postmortem changes of the central and peripheral human corneal nerves by exvivo laser-scanning confocal microscopy (EVCM).


METHODS
24 eyes from 14 cadavers were retrieved at different time intervals after death and examined by EVCM. Five regions were examined in each eye: central, superior, inferior, temporal and nasal. In each region, corneal nerve images were categorised according to their anatomical location in the cornea into sub-basal, stromal and limbal nerves. Five nerve parameters were measured: density, orientation, diameter, numbers and branching pattern.


RESULTS
Exvivo confocal scanning of a motionless eye allows high quality imaging and tracking of corneal and limbal nerves. Stromal nerves from the sub-Bowman's plexus perforate the Bowman's zone and terminate in bulb-like structures, from each of which a leash of sub-basal nerves arises. Following death, sub-basal nerve parameters showed significant changes. The density decreased from 9.23+/-4.48 to 0.45+/-0.07 mm/mm(2), the diameter from 4.01+/-0.81 to 2.08+/-0.20 microm, the numbers from 8.3 to 1.0 and branching pattern from 39.38% to 0% (p<0.05) from day 1 to day 5 postmortem. Stromal and limbal nerves showed no significant changes in their density and diameter.


CONCLUSIONS
This study establishes a direct link between sub-basal nerves and the sub-Bowman's nerves via distinct terminal bulbs. Limbal nerves are the thickest, are seen in all quadrants and can be traced to the corneal centre. The sub-basal nerve plexus rapidly degenerates after death but stromal and limbal nerves survive during the first five days after death.
Al-Aqaba
Mouhamed A
MA
Division of Ophthalmology and Visual Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK.
Alomar
Thaer
T
Miri
Ammar
A
Fares
Usama
U
Otri
Ahmad Muneer
AM
Dua
Harmnider S
HS
D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D003315:Cornea / Q000294:innervation*; D005260:Female; D006801:Humans; D008297:Male; D018613:Microscopy, Confocal / Q000379:methods; D008875:Middle Aged; D011180:Postmortem Changes