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
Latin	l. limitans posterior corneae
*Anatomical terminology* [edit on Wikidata]

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).

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

Anatomy of the globe of the eye

Fibrous tunic (outer)

Sclera	Episcleral layer Schlemm's canal Trabecular meshwork

Cornea	Limbus layers Epithelium Bowman's Stroma Dua's layer Descemet's Endothelium

1:posterior segment 2:ora serrata 3:ciliary muscle 4:ciliary zonules 5:Schlemm's canal 6:pupil 7:anterior chamber 8:cornea 9:iris 10:lens cortex 11:lens nucleus 12:ciliary process 13:conjunctiva 14:inferior oblique muscule 15:inferior rectus muscule 16:medial rectus muscle 17:retinal arteries and veins 18:optic disc 19:dura mater 20:central retinal artery 21:central retinal vein 22:optic nerve 23:vorticose vein 24:bulbar sheath 25:macula 26:fovea 27:sclera 28:choroid 29:superior rectus muscle 30:retina

Uvea/vascular tunic (middle)

Choroid	Capillary lamina of choroid Bruch's membrane Sattler's layer

Ciliary body	Ciliary processes Ciliary muscle Pars plicata Pars plana

Iris	Stroma Pupil Iris dilator muscle Iris sphincter muscle

Retina (inner)

Layers	Inner limiting membrane Nerve fiber layer Ganglion cell layer Inner plexiform layer Inner nuclear layer Outer plexiform layer Outer nuclear layer External limiting membrane Layer of rods and cones Retinal pigment epithelium

Cells	Photoreceptor cells (Cone cell, Rod cell) → (Horizontal cell) → Bipolar cell → (Amacrine cell) → Retina ganglion cell (Midget cell, Parasol cell, Bistratified cell, Giant retina ganglion cells, Photosensitive ganglion cell) → Diencephalon: P cell, M cell, K cell, Muller glia

Other	Macula Foveola Fovea centralis Parafovea Perifovea Optic disc Optic cup Ora serrata

Anatomical regions of the eye

Anterior segment	Adnexa Fibrous tunic Anterior chamber Aqueous humor Iris Posterior chamber Ciliary body Lens Capsule of lens Zonule of Zinn

Posterior segment	Vitreous chamber Vitreous humor Retina Choroid

Other

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