Editing Bowman's layer

{{Short description|Layer in the cornea of the eye}}
{{Infobox anatomy
| Name        = Bowman's layer
| Latin       = lamina limitans anterior corneae
| Image       = Vertical section human cornea-Gray871.png
| Caption     = Vertical section of human cornea from near the margin. Magnified. {{ordered list |style=text-align: left;
    |[[Epithelium]]
    |Anterior elastic lamina
    |[[substantia propria]]
    |[[Descemet's membrane|Posterior elastic lamina]]
    |[[corneal endothelium|Endothelium]] of the [[anterior chamber]]
    }}{{ordered list |style=text-align: left; |list_style_type=lower-alpha
    |Oblique fibers in the anterior layer of the [[substantia propria]]
    |Lamellae, the fibers of which are cut across, producing a dotted appearance
    |[[Corneal]] corpuscles appearing [[wikt:fusiform|fusiform]] in section
    |Lamellae, the fibers of which are cut longitudinally
    |Transition to the [[sclera]], with more distinct fibrillation, and surmounted by a thicker [[epithelium]]
    |Small bloodvessels cut across near the margin of the [[cornea]]
    }}
| Image2      =
| Caption2    =
| System      =
| Precursor   =
}}
The '''Bowman's layer''' ('''Bowman's membrane''', '''anterior limiting lamina''', '''anterior elastic lamina''') is a smooth, acellular, nonregenerating layer, located between the superficial [[epithelium]] and the [[Stroma of cornea|stroma]] in the [[cornea]] of the [[human eye|eye]]. It is composed of strong, randomly oriented [[collagen]] [[fibril]]s in which the smooth anterior surface faces the epithelial [[basement membrane]] and the posterior surface merges with the collagen lamellae of the corneal stroma proper.<ref>Kenyon, KR. Morphology and pathologic responses of the cornea to disease. In: Smolin G, Thoft RA, eds. The Cornea. Scientific Foundations and Clinical Practice. Boston: Little, Brown & Co.; 1983:45.</ref>

In adult humans, Bowman's layer is 8-12 [[micrometres|μm]] thick.<ref>Hogan MJ, Alvarado JA, Weddell E: Histology of the Human Eye. Philadelphia: WB Saunders, 1971</ref> With ageing, this layer becomes thinner.

The function of the Bowman's layer remains unclear and it appears to have no critical function in corneal physiology.<ref>{{cite journal | last1 = Wilson | first1 = SE | last2 = Hong | first2 = JW | date = Jul 2000 | title = Bowman's layer structure and function: critical or dispensable to corneal function? A hypothesis | journal = Cornea | volume = 19 | issue = 4| pages = 417–20 | doi=10.1097/00003226-200007000-00001| pmid = 10928749 | s2cid = 10793246 }}</ref> Recently, it is postulated that the layer may act as a physical barrier to protect the subepithelial nerve plexus and thereby  hastens epithelial innervation and sensory recovery. Moreover, it may also serve as a barrier that prevents direct traumatic contact with the corneal stroma and hence it is highly involved in stromal wound healing and the associated restoration of anterior corneal transparency at the morphological level.<ref>{{cite journal | last1 = Lagali | first1 = N | last2 = Germundsson | first2 = J | last3 = Fagerholm | first3 = P | date = Sep 2009 | title = The role of Bowman layer in corneal regeneration after phototherapeutic keratectomy: a prospective study using in vivo confocal microscopy | journal = Invest Ophthalmol Vis Sci | volume = 50 | issue = 9| pages = 4192–8 | doi = 10.1167/iovs.09-3781 | pmid = 19407024 | doi-access = free }}</ref>

Part of the Bowman's layer is ablated by the [[photorefractive keratectomy]] refractive surgery (commonly known as PRK). As the layer is non-generative, the section of the layer ablated in the procedure is lost forever.

== History ==
The Bowman's layer is named after Sir [[Sir William Bowman, 1st Baronet|William Bowman]] (1816–1892), an English [[physician]], [[anatomist]] and [[ophthalmologist]], who discovered this structure.  Bowman's layer is not a true basement membrane, despite being originally referred to as such.<ref>{{cite book|editor-last=Mills|editor-first=Stacey|title=Histology for Pathologists|edition=5th|page=337|publisher=Wolters Kluwer|year=2020|isbn=978-1496398949}}</ref><ref>{{cite journal|pmc=7283008|year=2020 |last1=Wilson |first1=S. E. |title=Bowman's layer in the cornea– structure and function and regeneration |journal=Experimental Eye Research |volume=195 |page=108033 |doi=10.1016/j.exer.2020.108033 |pmid=32339517 }}</ref>

==See also==
* [[Refractive surgery]]
* [[Descemet's membrane]]

==References==
<references />

==External links==
* {{BUHistology|08002loa}}
* [https://web.archive.org/web/20060221183020/http://www.sheinman.com/Aanatomyp4.htm Diagram at sheinman.com]
* [https://web.archive.org/web/20070213212011/http://www.laservue.net/images/cornea_crosssection_en.jpg Diagram at cornea_crosssection_en.jpg]

{{Eye}}
{{Authority control}}

[[Category:Human eye anatomy]]
[[Category:Anatomy named for one who described it]]

[[de:Hornhaut#Bowman-Membran]]