corneal epithelium
{{Short description|Outermost layer of the cornea}}
{{distinguish|text=the corneal endothelium}}
{{Infobox anatomy
| Name = Corneal epithelium
| Latin = Epithelium anterius corneae
| Image = Vertical section human cornea-Gray871.png
| Caption = Vertical section of human cornea from near the margin. (Waldeyer.) Magnified. {{ordered list |style=text-align: left;
|1=Epithelium
|5=Endothelium of the anterior chamber
}}{{ordered list |list_style_type=lower-alpha |style=text-align: left;
|1=Oblique fibers in the anterior layer of the substantia propria
|2=Lamellae, the fibers of which are cut across, producing a dotted appearance
|3=Corneal corpuscles appearing fusiform in section
|4=Lamellae, the fibers of which are cut longitudinally
|5=Transition to the sclera, with more distinct fibrillation, and surmounted by a thicker epithelium
|6=Small blood vessels cut across near the margin of the cornea
}}
| Image2 =
| Caption2 =
| System =
| Precursor =
}}
The corneal epithelium (epithelium corneae anterior layer) is made up of epithelial tissue and covers the front of the cornea. It acts as a barrier to protect the cornea, resisting the free flow of fluids from the tears, and prevents bacteria from entering the epithelium and corneal stroma.
Anatomy
The corneal epithelium consists of several layers of cells. The cells of the deepest layer are columnar, known as basal cells which are attached by multiprotein complexes known as hemidesmosomes to an underlying basement membrane.{{cite book |last1=John F |first1=Salmon |title=Kanski's Clinical ophthalmology |publisher=Elsevier |page=204 |edition=9 |chapter=Eyelids}} Then follow two or three layers of polyhedral cells, commonly known as wing cells. The majority of these are prickle cells, similar to those found in the stratum mucosum of the cuticle. Lastly, there are three or four layers of squamous cells, with flattened nuclei. The layers of the epithelium are constantly undergoing mitosis. Basal and wing cells migrate to the anterior of the cornea, while squamous cells age and slough off into the tear film.
Central thickness of corneal epithelial layer is approximately 50 to 52 μm.{{cite journal |last1=Reinstein |first1=Dan Z. |last2=Archer |first2=Timothy J. |last3=Gobbe |first3=Marine |last4=Silverman |first4=Ronald H. |last5=Coleman |first5=D. Jackson |title=Epithelial Thickness in the Normal Cornea: Three-dimensional Display With Very High Frequency Ultrasound |journal= Journal of Refractive Surgery |date=2008 |volume=24 |issue=6 |pages=571–581 |doi=10.3928/1081597X-20080601-05 |pmid=18581782 |pmc=2592549 |issn=1081-597X}}
Cornea cell LASIK complication
Epithelial ingrowth is a LASIK complication in which cells from the cornea surface layer (epithelial cells) begin to grow underneath the corneal flap. This complication is not present in PRK or other non-flap vision correction procedures.
See also
Disorders
External links
- [https://web.archive.org/web/20070614093245/http://www.lasikbenefitsusa.com/lasik-facts/corneaingrowth.html Epithelium Ingrowth After LASIK]
References
{{Reflist}}
{{Eye}}
{{Epithelial types}}
{{Authority control}}
{{DEFAULTSORT:Corneal Epithelium}}