choroidal

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choroid plexus

WordNet

1. a highly vascular membrane in the eye between the retina and the sclera; a dark pigmentation minimizes the scattering of light inside the eye (同)choroid coat

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/01/17 10:58:42」(JST)

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Choroid
Schematic cross section of the human eye; choroid is shown in purple.
Interior of anterior half of bulb of eye. (Choroid labeled at right, second from the bottom.)
Latin	choroidea
Gray's	subject #225 1009
Artery	short posterior ciliary arteries, long posterior ciliary arteries
MeSH	Choroid

The choroid, also known as the choroidea or choroid coat, is the vascular layer of the eye, containing connective tissue, and lying between the retina and the sclera. The human choroid is thickest at the far extreme rear of the eye (at 0.2 mm), while in the outlying areas it narrows to 0.1 mm. The choroid provides oxygen and nourishment to the outer layers of the retina. Along with the ciliary body and iris, the choroid forms the uveal tract.

The structure of the choroid is generally divided into four layers:

• Haller's layer - outermost layer of the choroid consisting of larger diameter blood vessels;
• Sattler's layer - layer of medium diameter blood vessels;
• Choriocapillaris - layer of capillaries; and
• Bruch's membrane (synonyms: Lamina basalis, Complexus basalis, Lamina vitra) - innermost layer of the choroid.

Blood supply

There are two circulations of the eye: the retinal (in the retina) and uveal, supplied in humans by posterior ciliary arteries, originating from the ophthalmic artery. The arteries of the uveal circulation, supplying the uvea and outer and middle layers of the retina, are branches of the ophthalmic artery and enter the eyeball without passing with the optic nerve. The retinal circulation, on the other hand, derives its circulation from the central retinal artery, also a branch of the ophthalmic artery, but passing in conjunction with the optic nerve. They are branching in a segmental distribution to the end arterioles and not anastomoses. This is clinically significant for diseases affecting choroidal blood supply. The macula responsible for central vision and the anterior part of the optic nerve are dependent on choroidal blood supply.

In bony fish

Teleosts bear a body of capillary adjacent to the optic nerve called the choroidal gland. Though its function is not known, it is believed to be a supplemental oxygen carrier.

Mechanism

Melanin, a darkly colored pigment, helps the choroid limit uncontrolled reflection within the eye that would potentially result in the perception of confusing images. In humans and most other primates, melanin occurs throughout the choroid. In albino humans, frequently melanin is absent and vision is low. In many animals, however, the partial absence of melanin contributes to superior night vision. In these animals, melanin is absent from a section of the choroid and within that section a layer of highly reflective tissue, the tapetum lucidum, helps to collect light by reflecting it in a controlled manner. The uncontrolled reflection of light from dark choroid produces the photographic red-eye effect on photos, whereas the controlled reflection of light from the tapetum lucidum produces eyeshine (see Tapetum lucidum).

See also

• Chorioretinitis
• Uveitis

Additional images

• Illustration depicting main structures of the eye

• Iris, front view

• The terminal portion of the optic nerve and its entrance into the eyeball, in horizontal section

• The interior of the posterior half of the left eyeball

• Structures of the eye labeled

• This image shows another labeled view of the structures of the eye

• Calf's eye dissected to expose the choroid: its tapetum lucidum is iridescent blue

References

External links

• BU Histology Learning System: 08008loa

UpToDate Contents

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English Journal

• Bilateral choroidal osteoma: visual acuity at 45-year follow-up.

• Hasanreisoglu M1, Shields JA, Mashayekhi A, Shields CL.
• Retinal cases & brief reports.Retin Cases Brief Rep.2015 Summer;9(3):239-41. doi: 10.1097/ICB.0000000000000148.
• PURPOSE: To report a case of bilateral choroidal osteoma, which demonstrated different visual outcomes in both eyes over a long follow-up of 45 years.METHODS: Case report.RESULTS: After 45 years of follow-up, choroidal osteoma showed slight enlargement in each eye and choroidal neovascularization an
• PMID 25790319

• Multifocal choroiditis and panuveitis presenting with progressive equatorial linear streaks: evolution of schlaegel lines documented with multimodal imaging.

• Somkijrungroj T1, Pearlman JA, Gonzales JA.
• Retinal cases & brief reports.Retin Cases Brief Rep.2015 Summer;9(3):214-7. doi: 10.1097/ICB.0000000000000141.
• PURPOSE: To describe the progressive, peripheral linear streaks of the equatorial retina, known as Schlaegel lines, in multifocal choroiditis and panuveitis (MCP).METHODS: A case report of a 13-year-old girl with MCP showed progression of retinal linear streaks. Extensive systemic and ophthalmologic
• PMID 25790317

• Indocyanine green angiographic evidence of choroiditis in scleroderma.

• Abdellatief A1, Balasubramaniam SC, Grube TJ, Gonzalez Santiago TM, Osborn TG, Pulido JS.
• Retinal cases & brief reports.Retin Cases Brief Rep.2015 Summer;9(3):231-4. doi: 10.1097/ICB.0000000000000146.
• PURPOSE: The purpose of this case report was to demonstrate evidence of indocyanine green angiography leakage consistent with choroiditis in a patient with scleroderma.METHODS: In this case report, the patient underwent a variety of tests and examinations, including systemic evaluation, full ocular
• PMID 25769052

Japanese Journal

• 私の経験 時間跳躍3D観察法-Time Skip 3D observation-でわかる眼底変化

• 眼科 58(10), 1103-1107, 2016-10
• NAID 40020986235

• 特発性傍乳頭脈絡膜新生血管膜にベバシズマブ硝子体注射を施行した1例 (第69回日本臨床眼科学会講演集(8))

• 臨床眼科 70(10), 1645-1651, 2016-10
• NAID 40020973118

• A Case of Anterior Choroidal Artery Occlusion Caused by Stuck of Microguidewire during Cerebral Aneurysm Embolization

• JNET : journal of neuroendovascular therapy : official journal of the Japanese Society for Neuroendovascular Therapy 10(4), 206-211, 2016-09
• NAID 40020951152

Related Links

• Choroidal | Define Choroidal at Dictionary.com

British Dictionary definitions for choroidal Expand choroid / ˈkɔːrɔɪd / adjective 1. resembling the chorion, esp in being vascular noun 2. the brownish vascular membrane of the eyeball between the sclera and the retina C18: from ...

• choroidal - definition of choroidal by Medical dictionary

cho·roi·dal (kō-roy'dăl), Relating to the choroid (choroidea). cho·roi·dal (kə-roid′l, kô-) adj. Of or relating to the choroid. cho·roi·dal (kōr-oyd'ăl) Relating to the choroid (choroidea). choroidal pertaining to or emanating from the choroid.