The Bowman layer (Bowman's membrane, anterior limiting lamina, anterior elastic lamina) is a smooth, acellular, nonregenerating layer, located between the superficial
epithelium
Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellul ...
and the
stroma in the
cornea of the
eye
Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conv ...
. It is composed of strong, randomly oriented
collagen
Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the whole ...
fibrils in which the smooth anterior surface faces the epithelial
basement membrane
The basement membrane is a thin, pliable sheet-like type of extracellular matrix that provides cell and tissue support and acts as a platform for complex signalling. The basement membrane sits between Epithelium, epithelial tissues including mesot ...
and the posterior surface merges with the collagen lamellae of the corneal stroma proper.
In adult humans, Bowman layer is 8-12
μm
The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...
thick. With ageing, this layer becomes thinner.
The function of the Bowman layer remains unclear and appears to have no critical function in corneal physiology. 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.
Part of the Bowman 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 layer is named after Sir
William Bowman William, Willie, Will, Bill, or Billy Bowman may refer to:
Sportspeople
* Bill Bowman (baseball) (1867–1944), American baseball player for the Chicago Colts
* William Bowman (fencer) (1881–1947), American Olympic fencer
* Bill Bowman (American ...
(1816–1892), an English
physician,
anatomist and
ophthalmologist
Ophthalmology ( ) is a surgery, surgical subspecialty within medicine that deals with the diagnosis and treatment of eye disorders.
An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Followin ...
, who discovered this structure. Bowman layer is not a true basement membrane.
[ Mills, Stacey (ed). Histology for Pathologists. 5th ed., pp.337. Wolters Kluwer, 2020. ]
See also
*
Refractive surgery
Refractive eye surgery is optional eye surgery used to improve the refractive state of the eye and decrease or eliminate dependency on glasses or contact lenses. This can include various methods of surgical remodeling of the cornea (keratomileu ...
*
Descemet's membrane
References
External links
*
Diagram at sheinman.comDiagram at cornea_crosssection_en.jpg
{{Authority control
Human eye anatomy
de:Hornhaut#Bowman-Membran