Editing Cornea (section)

===Nerve supply===
The cornea is one of the most sensitive tissues of the body, as it is densely innervated with sensory nerve fibres via the [[Ophthalmic nerve|ophthalmic division]] of the [[trigeminal nerve]] by way of 70–80 [[long ciliary nerves]]. Research suggests the density of pain receptors in the cornea is 300–600 times greater than skin and 20–40 times greater than [[dental pulp]],<ref>{{cite book|last=Belmonte|first=Carlos|title=Neurobiology of Nociceptors|year=1996|publisher=Oxford University Press|isbn=9780198523345|page=146|author2=Gallar Juana|chapter=6: Corneal Nociceptors|doi=10.1093/acprof:oso/9780198523345.001.0001}}</ref> making any injury to the structure excruciatingly painful.<ref>{{cite web|last=Karmel|first=Miriam|title=Addressing the Pain of Corneal Neuropathy|url=https://www.aao.org/eyenet/article/addressing-pain-of-corneal-neuropathy|work=EyeNet|publisher=American Academy of Ophthalmology|access-date=30 December 2017|date=July 2010}}</ref>

The ciliary nerves run under the endothelium and exit the eye through holes in the sclera apart from the optic nerve (which transmits only optic signals).<ref name="ReferenceA"/> The nerves enter the cornea via three levels; ''scleral, episcleral and conjunctival''. Most of the bundles give rise by subdivision to a network in the stroma, from which fibres supply the different regions. The three networks are, ''midstromal, subepithelial/sub-basal, and epithelial.'' The receptive fields of each nerve ending are very large, and may overlap.

Corneal nerves of the subepithelial layer terminate near the superficial epithelial layer of the cornea in a [[logarithmic spiral]] pattern.<ref name="Yu">{{cite journal |doi=10.1167/iovs.06-1192 |title=Transgenic Corneal Neurofluorescence in Mice: A New Model for in Vivo Investigation of Nerve Structure and Regeneration |year=2007 |last1=Yu |first1=C. Q. |last2=Rosenblatt |first2=M. I. |journal=Investigative Ophthalmology & Visual Science |volume=48 |issue=4 |pmid=17389482 |pages=1535–42|doi-access=free }}</ref> The density of epithelial nerves decreases with age, especially after the seventh decade.<ref>{{cite journal |doi=10.1016/j.exer.2010.07.007 |title=Mapping the entire human corneal nerve architecture |year=2010 |last1=He |first1=Jiucheng |last2=Bazan |first2=Nicolas G. |last3=Bazan |first3=Haydee E.P. |journal=Experimental Eye Research |volume=91 |issue=4 |pages=513–23 |pmid=20650270 |pmc=2939211}}</ref>