Descemet's membrane (
or the Descemet membrane) is the
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 ...
that lies between the corneal proper substance, also called
stroma, and the
endothelial layer of the
cornea
The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Along with the anterior chamber and lens, the cornea refracts light, accounting for approximately two-thirds of the eye's total optical power ...
. It is composed of different kinds of collagen (Type IV and VIII) than the stroma. The endothelial layer is located at the posterior of the cornea. Descemet's membrane, as the basement membrane for the endothelial layer, is secreted by the single layer of squamous epithelial cells that compose the endothelial layer of the cornea.
Structure
Its thickness ranges from 3 μm at birth to 8–10 μm in adults.
[Johnson DH, Bourne WM, Campbell RJ: The ultrastructure of Descemet's membrane. I. Changes with age in normal cornea. Arch Ophthalmol 100:1942, 1982]
The corneal endothelium is a single layer of squamous cells covering the surface of the cornea that faces the
anterior chamber
The anterior chamber ( AC) is the aqueous humor-filled space inside the eye between the iris and the cornea's innermost surface, the endothelium. Hyphema, anterior uveitis and glaucoma are three main pathologies in this area. In hyphema, blood f ...
.
Clinical significance
![KF ring 2](https://upload.wikimedia.org/wikipedia/commons/4/47/KF_ring_2.jpg)
Significant damage to the membrane may require a corneal transplant. Damage caused by the hereditary condition known as
Fuchs dystrophy (q.v.)—where Descemet's membrane progressively fails and the cornea thickens and clouds because the exchange of nutrients/fluids between the cornea and the rest of the eye is interrupted—can be reversed by surgery. The surgeon can scrape away the damaged Descemet membrane and insert/transplant a new membrane harvested from the eye of a donor.
In the process most of the squamous cells of the donor membrane survive to dramatically and emphatically reverse the corneal deterioration (see
DMEK surgery).
Descemet's membrane is also a site of copper deposition in patients with
Wilson's disease
Wilson's disease is a genetic disorder in which excess copper builds up in the body. Symptoms are typically related to the brain and liver. Liver-related symptoms include vomiting, weakness, fluid build up in the abdomen, swelling of the legs, ...
or other liver diseases, leading to formation of
Kayser-Fleischer rings.
History
It is also known as the Posterior limiting elastic lamina, lamina elastica posterior, and membrane of Demours. It was named after French physician
Jean Descemet (1732–1810).
See also
*
Haab's striae
Haab's striae, or Descemet's tears, are horizontal breaks in the Descemet membrane associated with congenital glaucoma
Primary juvenile glaucoma is glaucoma that develops due to ocular hypertension and is evident either at birth or within the fir ...
*
Kayser–Fleischer ring
Kayser–Fleischer rings (KF rings) are dark rings that appear to encircle the cornea of the eye. They are due to copper deposition in the Descemet's membrane as a result of particular liver diseases. They are named after German ophthalmologists ...
*
Pierre Demours
References
Histology A text and atlas. Michael H.Ross and Wojciech Pawlina 5th Edition 2006
External links
*
Diagram at dryeyezone.com
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Human eye anatomy