WordNet

the whitish fibrous membrane (albuginea) that with the cornea forms the outer covering and protection of the eyeball (同)sclerotic coat
small veins in the sclera near the corneal margin; empty into the anterior ciliary veins (同)venae_episclerales
tributaries of the anterior ciliary veins that drain the sclera of the eye (同)venae sclerales

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鞏膜(きょうまく)(角膜とともに眼球をおおっている堅くて白い膜)

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/02/27 05:17:40」(JST)

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"White of the eye" redirects here. For the film, see White of the Eye (film).

The sclera (from the Greek skleros, meaning hard^[1]), also known as the white of the eye, is the opaque, fibrous, protective, outer layer of the eye containing collagen and elastic fiber.^[2] In humans the whole sclera is white, contrasting with the coloured iris, but in other mammals the visible part of the sclera matches the colour of the iris, so the white part does not normally show. In the development of the embryo, the sclera is derived from the neural crest.^[3] In children, it is thinner and shows some of the underlying pigment, appearing slightly blue. In the elderly, fatty deposits on the sclera can make it appear slightly yellow.

Human eyes are somewhat distinctive in the animal kingdom in that the sclera is very plainly visible whenever the eye is open. This is not just due to the white color of the human sclera, which many other species share, but also to the fact that the human iris is relatively small and comprises a significantly smaller portion of the exposed eye surface compared to other animals. It is theorized that this adaptation evolved because of our social nature as the eye became a useful communication tool in addition to a sensory organ. It is believed that the conspicuous sclera of the human eye makes it easier for one individual to infer where another individual is looking, increasing the efficacy of this particular form of nonverbal communication.^[4] Animal researchers have also found that, in the course of their domestication, dogs have also developed the ability to pick up visual cues from the eyes of humans, making them one of only two species known to seek visual cues from another individual's eyes. Dogs do not seem to use this form of communication with one another and only look for visual information from the eyes of humans.^[5]

Structure

The sclera forms the posterior five-sixths of the connective tissue coat of the globe. It is continuous with the dura mater and the cornea, and maintains the shape of the globe, offering resistance to internal and external forces, and provides an attachment for the extraocular muscle insertions. The sclera is perforated by many nerves and vessels passing through the posterior scleral foramen, the hole that is formed by the optic nerve. At the optic disc the outer two-thirds of the sclera continues with the dura mater (outer coat of the brain) via the dural sheath of the optic nerve. The inner third joins with some choroidal tissue to form a plate (lamina cribrosa) across the optic nerve with perforations through which the optic fibers (fasciculi) pass. The thickness of the sclera varies from 1mm at the posterior pole to 0.3 mm just behind the rectus muscle insertions. The sclera's blood vessels are mainly on the surface. Along with the vessels of the conjunctiva (which is a thin layer covering the sclera), those in the episclera render the inflamed eye bright red.^[6]

In many vertebrates, the sclera is reinforced with plates of cartilage or bone, together forming a circular structure called the scleral ring. In primitive fish, this ring consists of four plates, but the number is lower in many living ray-finned fishes, and much higher in lobe-finned fishes, various reptiles, and birds. The ring has disappeared in many groups, including living amphibians, some reptiles and fish, and all mammals.^[7]

The eyes of all non-human primates are dark with small, barely visible sclera. See Cooperative eye hypothesis

Histology

The collagen of the sclera is continuous with the cornea. From outer to innermost, the four layers of the sclera are:

episclera
stroma
lamina fusca
endothelium

The sclera is opaque due to the irregularity of the Type I ^[8] collagen fibers, as opposed to the near-uniform thickness and parallel arrangement of the corneal collagen. Moreover, the cornea bears more mucopolysaccharide (a carbohydrate that has among its repeating units a nitrogenous sugar, hexosamine) to embed the fibrils.

The cornea, unlike the sclera, has five layers. The middle, thickest layer is also called the stroma. The sclera, like the cornea, contains a basal endothelium, above which there is the lamina fusca, containing a high count of pigment cells.^[6]

Sometimes, very small gray-blue spots can appear on the sclera, a harmless condition called scleral melanocytosis.

Gallery

Schematic diagram of the human eye.
Interior of anterior half of bulb of eye.
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

References

^ Mosby’s Medical, Nursing and Allied Health Dictionary, Fourth Edition, Mosby-Year Book Inc., 1994, p. 1402
^ Cassin, B. and Solomon, S. Dictionary of Eye Terminology. Gainesville, Florida: Triad Publishing Company, 1990.
^ Hermann D. Schubert. Anatomy of the Orbit http://www.nyee.edu/pdf/schubert.pdf
^ Michael Tomasello, Brian Hare, Hagen Lehmann, Josep Call. "Reliance on head versus eyes in the gaze following of great apes and human infants: the cooperative eye hypothesis" http://www.chrisknight.co.uk/wp-content/uploads/2008/06/eyes-cooperation.pdf
^ Director and Producer: Dan Child, Executive Producer: Andrew Kohen (2010-01-06). "The Secret Life of the Dog". Horizon. BBC. BBC2. http://www.bbc.co.uk/programmes/b00pssgh.
^ ^a ^b "eye, human."Encyclopædia Britannica from Encyclopædia Britannica 2006 Ultimate Reference Suite DVD 2009
^ Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia, PA: Holt-Saunders International. p. 461. ISBN 0-03-910284-X.
^ Keeley, FW; Morin, JD; Vesely, S (1984 Nov). "Characterization of collagen from normal human sclera.". Experimental eye research 39 (5): 533–42. PMID 6519194.

External links

BU Histology Learning System: 08008loa
Atlas of anatomy at UMich eye_1—"Sagittal Section Through the Eyeball"

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 骨形成不全症：臨床的特徴および診断 osteogenesis imperfecta clinical features and diagnosis
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4. 児童虐待の整形外科的症状の鑑別診断 differential diagnosis of the orthopedic manifestations of child abuse
5. 骨折のマネージメントの一般原則：小児における骨折のパターンおよび種類 general principles of fracture management fracture patterns and description in children

English Journal

Morphological changes in the conjunctiva, episclera and sclera following short-term miniscleral contact lens wear in rigid lens neophytes.

Alonso-Caneiro D1, Vincent SJ2, Collins MJ2.
Contact lens & anterior eye : the journal of the British Contact Lens Association.Cont Lens Anterior Eye.2016 Feb;39(1):53-61. doi: 10.1016/j.clae.2015.06.008. Epub 2015 Jul 17.
PURPOSE: To quantify the influence of short-term wear of miniscleral contact lenses on the morphology of the corneo-scleral limbus, the conjunctiva, episclera and sclera.METHODS: OCT images of the anterior eye were captured before, immediately following 3h of wear and then 3h after removal of a mini
PMID 26189941

SCLERAL AND CHOROIDAL THICKNESS IN SECONDARY HIGH AXIAL MYOPIA.

Shen L1, You QS, Xu X, Gao F, Zhang Z, Li B, Jonas JB.
Retina (Philadelphia, Pa.).Retina.2016 Jan 5. [Epub ahead of print]
PURPOSE: To assess differences in scleral and choroidal thickness between eyes with secondary high axial myopia caused by congenital glaucoma, eyes with primary high axial myopia, and nonhighly myopic eyes.METHODS: The study consisted of 301 Chinese individuals with a mean age of 23.9 ± 22.6 years
PMID 26735565

Transscleral Controlled Delivery of Geranylgeranylaceton Using a Polymeric Device Protects Rat Retina Against Light Injury.

Nagai N1, Kaji H2, Nishizawa M3, Nakazawa T4, Abe T5.
Advances in experimental medicine and biology.Adv Exp Med Biol.2016;854:471-7. doi: 10.1007/978-3-319-17121-0_63.
We evaluated the effects of a transscleral drug delivery device, consisting of a reservoir and controlled-release cover, which were made of photopolymerized polyethylene glycol dimethacrylate and triethylene glycol dimethacrylate, combined at different ratios. Geranylgeranylacetone (GGA), a heat-sho
PMID 26427448

A review of the surgical options for the correction of presbyopia.

Gil-Cazorla R1, Shah S2, Naroo SA3.
The British journal of ophthalmology.Br J Ophthalmol.2016 Jan;100(1):62-70. doi: 10.1136/bjophthalmol-2015-306663. Epub 2015 Apr 23.
Presbyopia is an age-related eye condition where one of the signs is the reduction in the amplitude of accommodation, resulting in the loss of ability to change the eye's focus from far to near. It is the most common age-related ailments affecting everyone around their mid-40s. Methods for the corre
PMID 25908836

Japanese Journal

Scleral birefringence as measured by polarization-sensitive optical coherence tomography and ocular biometric parameters of human eyes in vivo

Yamanari Masahiro,Nagase Satoko,Fukuda Shinichi,Ishii Kotaro,Tanaka Ryosuke,Yasui Takeshi,Oshika Tetsuro,Miura Masahiro,Yasuno Yoshiaki
Biomedical Optics Express 5(5), 1391-1402, 2014-05
… SHG images of porcine sclera, measured on the external surface at the superior side to the cornea, showed highly aligned collagen fibers parallel to the limbus. …
NAID 120005451860

症例骨形成不全症に僧帽弁閉鎖不全症と心房中隔瘤を合併した1例

永井竜,服部隆司,重田治
胸部外科 = The Japanese journal of thoracic surgery 67(1), 79-82, 2014-01
NAID 40019921208

Partial stapedectomyを施行したvan der Hoeve症候群例

草野純子,山本典生,平海晴一 [他],坂本達則,伊藤壽一
耳鼻咽喉科臨床 107(4), 287-291, 2014
… Blue sclera was noted and the patient had a history of osteogenesis imperfecta with several instances of bone fractures. …
NAID 130003395641

白内障手術後10 年を経過して眼内炎が発症したWerner 症候群の1 症例

岡本洋幸,林麗如,筑田眞
Dokkyo journal of medical sciences 40(3), 185-188, 2013-10-25
Werner 症候群は老人様顔貌,強皮症様皮膚変化,若年性白内障を特徴とする疾患である.発症は100 万人あたり3〜45 人とされている.今回,われわれは白内障術後10 年以上経過したにも関わらず強膜創の閉鎖不全が感染の原因と考えられる眼内炎の症例(41 歳,男性)を経験した.Werner 症候群には白内障を合併することが多く,術後も創傷治癒は遅延しやすいため感染のリスクが高い.眼科的な長期の経過 …
NAID 110009633259

Related Pictures

★リンクテーブル★

リンク元	「強膜」「強膜炎」「scleral」

「強膜」

Sclera
	The sclera, as separated from the cornea by the corneal limbus.
Gray's	subject #225 1006
Artery	anterior ciliary arteries, long posterior ciliary arteries, short posterior ciliary arteries
MeSH	Sclera

　　[★]

英: sclera, sclerae
関: 眼、眼球

強膜　角膜
脈絡叢　毛様体　虹彩
網膜
厚さ：視神経が眼球に入る部位(1mm, 最も厚い)、角膜との境界部より6mm後方(0.4mm, 最も薄い)。

「強膜炎」

　　[★]

英: scleritis, leucitis
関: 上強膜炎、強膜 sclera

「scleral」

　　[★]

adj.

強膜の

関: sclera、sclerae

[1] Mosby’s Medical, Nursing and Allied Health Dictionary, Fourth Edition, Mosby-Year Book Inc., 1994, p. 1402

[Cassin-2] Cassin, B. and Solomon, S. Dictionary of Eye Terminology. Gainesville, Florida: Triad Publishing Company, 1990.

[3] Hermann D. Schubert. Anatomy of the Orbit http://www.nyee.edu/pdf/schubert.pdf

[4] Michael Tomasello, Brian Hare, Hagen Lehmann, Josep Call. "Reliance on head versus eyes in the gaze following of great apes and human infants: the cooperative eye hypothesis" http://www.chrisknight.co.uk/wp-content/uploads/2008/06/eyes-cooperation.pdf

[secretlife-5] Director and Producer: Dan Child, Executive Producer: Andrew Kohen (2010-01-06). "The Secret Life of the Dog". Horizon. BBC. BBC2. http://www.bbc.co.uk/programmes/b00pssgh.

[eb-6] "eye, human."Encyclopædia Britannica from Encyclopædia Britannica 2006 Ultimate Reference Suite DVD 2009

[VB-7] Romer, Alfred Sherwood; Parsons, Thomas S. (1977). The Vertebrate Body. Philadelphia, PA: Holt-Saunders International. p. 461. ISBN 0-03-910284-X.

[8] Keeley, FW; Morin, JD; Vesely, S (1984 Nov). "Characterization of collagen from normal human sclera.". Experimental eye research 39 (5): 533–42. PMID 6519194.

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sclera