sclera


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Related to sclera: conjunctiva, Blue Sclera

sclera

 [skle´rah] (L.)
the tough, white outer coat of the eyeball, covering approximately the posterior five-sixths of its surface, continuous anteriorly with the cornea and posteriorly with the external sheath of the optic nerve. adj., adj scle´ral.
The sclera and other eye structures. From Lammon et al., 1995.
blue sclera abnormal blueness of the sclera; it is a prominent feature of osteogenesis imperfecta and is also seen in certain other conditions. (See Atlas 1, Part B.)

scle·ra

, pl.

scle·ras

,

scler·ae

(sklē'ră, -ăz, -ē), [TA]
A portion of the fibrous layer forming the outer envelope of the eyeball, except for its anterior sixth, which is the cornea.
[Mod. L. fr. G. sklēros, hard]

sclera

(sklîr′ə)
n.
The tough white fibrous outer envelope of tissue covering all of the eyeball except the cornea. Also called sclerotic, sclerotic coat.

scle′ral adj.

scle·ra

, pl. scleras, pl. sclerae (skleră, -ăz, -ē) [TA]
A portion of the fibrous tunic forming the outer envelope of the eye, except for its anterior one sixth, which is the cornea.
Synonym(s): sclerotica.
[Mod. L. fr. G. sklēros, hard]

sclera

The white of the eye. The tough outer coating of dense, interwoven collagen fibrils visible through the transparent overlying CONJUNCTIVA.

sclera

or

sclerotic

the outer coat of the vertebrate eye to which are attached extrinsic muscles for moving the eyeball. The sclera is lined by a vascular layer, the CHOROID, except for the forward-facing part which is called the CORNEA and is transparent, with no underlying choroid.

Sclera

The tough, fibrous, white outer protective covering that surrounds the eye.

sclera 

The tough, white, opaque, fibrous outer tunic of the eyeball covering most of its surface (the cornea contributes 7% of, and completes, the outer tunic). Its anterior portion is visible and constitutes the 'white' of the eye. In childhood (or in pathological conditions) when the sclera is thin, it appears bluish, while in old age it may become yellowish, due to a deposition of fat. The sclera is thickest posteriorly (about 1 mm) and gradually becomes thinner towards the front of the eyeball. It is a sieve-like membrane at the lamina cribrosa. The sclera is pierced by three sets of apertures: (1) the posterior apertures round the optic nerve and through which pass the long and short posterior ciliary vessels and nerves; (2) the middle apertures, 4 mm behind the equator which give exit to the vortex veins; and (3) the anterior apertures through which pass the anterior ciliary vessels. The tendons of insertion of the extraocular muscles run into the sclera as parallel fibres and then spread out in a fan-shaped manner. The sclera is commonly considered to be divided into three layers from without inward: (1) the episclera, (2) the scleral stroma and (3) the suprachoroid (lamina fusca) which is interposed between choroid and sclera. Syn. sclerotic. Note: some authors consider the suprachoroid as belonging to the choroid. However, when choroid and sclera are separated part of the suprachoroid adheres to the choroid and part to the sclera. See cribriform plate; evisceration.
blue sclera A hereditary defect in which the sclera has a bluish appearance. The sclera is thinner than normal and is susceptible to rupture if the person engages in contact sports. It is often associated with fragility of the bones and deafness as part of a condition called osteogenesis imperfecta (fragilitas ossium, van der Hoeve's syndrome), with keratoconus or with acquired scleral thinning (e. g. necrotizing scleritis). Syn. blue sclerotic (Fig. S3). See Ehlers-Danlos syndrome; Marfan's syndrome.
Fig. S3 Blue scleraenlarge picture
Fig. S3 Blue sclera

scle·ra

, pl. scleras, pl. sclerae (skleră, -ăz, -ē) [TA]
Portion of fibrous layer forming outer envelope of eyeball, except for its anterior sixth, which is the cornea.
[Mod. L. fr. G. sklēros, hard]

Patient discussion about sclera

Q. My 11 y/o son eyes appear to have a slight yellow in the whites toward the corners. I am assuming he will need blood work, but does anyone have any idea what may be the cause?

A. If it's not a spot, but rather a diffuse color, it may be jaundice - high levels in the blood of a substance called bilirubin (http://en.wikipedia.org/wiki/Jaundice).

If your child is generally healthy, and this change appeared without any overt problem (e.g. liver disease or blood problem), or your child had fever or fasted recently, this jaundice may represents Gilbert syndrome. It's a syndrome of slightly elevated levels of bilirubin, and considered not dangerous.

You may read more here:http://www.nlm.nih.gov/medlineplus/ency/article/000301.htm

More discussions about sclera
References in periodicals archive ?
If we perform the experiment in vivo, the crosslinking agents need to be injected subconjunctivally and may not be distributed evenly on the surface of the sclera. The crosslinking effect could also be affected by other factors, such as catabolism in vivo, which will affect the final results of the study.
In the literature, recurrence rates of up to 38%-88% have been reported for the bare sclera technique (19, 20).
The minimally invasive ultraviolet sclera cross-linking apparatus used in this study was developed by Tianjin Eye Hospital and Suzhou Institute of Biomedical Engineering and Technology.
Yet by the time people notice the yellowish discoloration in the sclera, bilirubin levels are already well past cause for concern.
With the aid of a spring action scissors, the Pterygium was freed from the overlying conjunctiva and the underlying sclera by blunt dissection.
[1] The word ochronosis refers to the dark bluish discoloration of connective tissues including the sclera, cornea, auricular cartilage, heart valves, articular cartilage, tendons and ligaments.
The rectus muscles are originated in the posterior segment of the orbit and in this point they are fused and individualize themselves according to their approximation of the sclera adhering to the optical pedicle.
There are two additional case reports on IgG4-RD involving the sclera: one described an IgG4-RD flare in a patient with a long history of the disease (diagnosis based on extraorbital biopsy, submandibular gland biopsy) [5] and the other was a case of IgG4-related pachymeningitis with concomitant scleritis, uveitis, and orbital soft-tissue involvement [6].
There was no positive staining of human cells in the sclera of transplanted eyes or in contralateral noninjected control eyes in any of the rabbits (Figures 1-3 and data not shown).
The sclera undergoes several changes during the development and progression of myopia, including scleral thinning and weakening [3].
For recession surgery, medial rectus muscle was detached from the sclera after used suspensory suture.
Professor Sclera is a haughty verbal opponent; the mysterious Professor Oedda entangles Muzhduk in her bed and her occult leanings.