retinal pigment epithelium

(redirected from Pigmented layer)

retinal pigment epithelium (RPE) 

A brown monolayer of cells of the retina situated next to the choroid composed of cells joined by tight junctions and filled with pigment, mainly melanin and lipofuscin (Fig. R9). Depending upon the amount of pigment, the fundus will appear dark or light. The main functions of the RPE are: control of the flow of fluid and nutrients entering the retina (blood-retina barrier), absorption of scattered light, visual pigment metabolism, vitamin A metabolism which contributes to visual pigment regeneration, ingestion and digestion of photoreceptor discs (phagocytosis), retinal adhesion and synthesis of growth factors of adjacent tissues. A dysfunction of this tissue can be detected with the electrooculogram. See Bruch's membrane; Usher's syndrome.
Fig. R9 Schematic representation of the cells and layers of the central primate retina (1: retinal pigment epithelium; 2: layer of rods and cones; 3: external limiting membrane; 4: outer nuclear layer; 5: outer plexiform layer; 6: inner nuclear layer; 7: inner plexiform layer; 8: ganglion cell layer; 9: nerve fibre layer; 10: internal limiting membrane)enlarge picture
Fig. R9  Schematic representation of the cells and layers of the central primate retina (1: retinal pigment epithelium; 2: layer of rods and cones; 3: external limiting membrane; 4: outer nuclear layer; 5: outer plexiform layer; 6: inner nuclear layer; 7: inner plexiform layer; 8: ganglion cell layer; 9: nerve fibre layer; 10: internal limiting membrane)
References in periodicals archive ?
Which four-letter word, beginning with "U", is the pigmented layer of the eye, lying beneath the sclera and cornea, and comprising the iris, choroid and ciliary body?
Uveitis is the inflammation of the uvea, the pigmented layer that lies between the inner retina and the outer fibrous layer composed of the sclera and cornea.
"It's more common in fair skinned individuals with blue or green eyes, and individuals with abnormal brown spots affecting the pigmented layer of the eye.
Uveitis, which often has an autoimmune component, is the inflammation of the uvea, the pigmented layer that lies between the inner retina and the outer fibrous layer composed of the sclera and cornea.
Eventually, blindness results from photoreceptor loss associated with degeneration in the pigmented layer of the retina, called the retinal pigment epithelium, which is the site of damage that the company believes the hESC-derived RPE may be able to target for repair after administration.
Gene therapy has only been used to partially restore sight in people who are blind from defects in the pigmented layer of the eye, providing the same treatment for those who are blind through loss of photoreceptor cells - the cells that respond to light - has proven a greater challenge.
Eventually, blindness results from photoreceptor loss associated with regeneration in the pigmented layer of the retina, called the retinal pigment epithelium or RPE cell layer.
The blue bottle in the picture has a foamed layer inside and solid, pigmented layer outside.
This amended model can be used only if the scattering layer is the uppermost pigmented layer in the multilayer composite coating.
While it looks like any other tubing at first glance, a closer look reveals that the pigmented layer surrounds a separate but integrally bonded inner layer of natural PEEK.