Descemet's membrane
| Descemet's membrane | |
|---|---|
 Vertical section of human cornea from near the margin. (Waldeyer.) Magnified. 1. Epithelium. 2. Anterior elastic lamina. 3. substantia propria. 4. Posterior elastic lamina. (Descemet's membrane) 5. Endothelium of the anterior chamber. a. Oblique fibers in the anterior layer of the substantia propria. b. Lamellæ the fibers of which are cut across, producing a dotted appearance. c. Corneal corpuscles appearing fusiform in section. d. Lamellæ the fibers of which are cut longitudinally. e. Transition to the sclera, with more distinct fibrillation, and surmounted by a thicker epithelium. f. Small bloodvessels cut across near the margin of the cornea. | |
| Details | |
| Identifiers | |
| Latin | l. limitans posterior corneae |
| Dorlands /Elsevier | 12476281 |
Descemet's membrane is the basement membrane that lies between the corneal proper substance, also called stroma, and the endothelial layer of the cornea. It is composed of a different kind of collagen (Type VIII)[1] 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.[2]
The corneal endothelium is a single layer of squamous cells covering the surface of the cornea that faces the anterior chamber.
Clinical significance
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 and 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 or other liver diseases, leading to formation of Kayser-Fleischer rings.
History
It is also known as the Posterior limiting lamina, posterior elastic lamina, lamina elastica posterior, and membrane of Demours. It was named after French physician Jean Descemet (1732–1810).
See also
References
- ↑ "Tissue Distribution of Type VIII Collagen in Human Adult and Fetal Eyes" (PDF). Investigative Ophthalmology and Visual Science. 1991-08-01. Retrieved 2014-08-17.
- ↑ Johnson DH, Bourne WM, Campbell RJ: The ultrastructure of Descemet's membrane. I. Changes with age in normal cornea. Arch Ophthalmol 100:1942, 1982
Histology A text and atlas. Michael H.Ross and Wojciech Pawlina 5th Edition 2006
External links
- Histology image: 08002loa – Histology Learning System at Boston University
- Descemet membrane at the US National Library of Medicine Medical Subject Headings (MeSH)
- Diagram at dryeyezone.com
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