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Related to sclera: conjunctiva, Blue 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.)


, pl.




(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]


/scle·ra/ (sklēr´ah) pl. scle´rae   [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.scler´al


The tough white fibrous outer envelope of tissue covering all of the eyeball except the cornea. Also called sclerotic, sclerotic coat.

scle′ral adj.


Etymology: Gk, skleros, hard
the tough, inelastic white opaque membrane covering the posterior five sixths of the eyebulb. It maintains the size and form of the bulb and attaches to muscles that move the bulb. Posteriorly it is pierced by the optic nerve and, with the transparent cornea, makes up the outermost of three tunics covering the eyebulb.


, 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]


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




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.


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


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


, 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]


pl. sclerae [L.] the tough, usually white, outer coat of the eyeball, covering all the posterior surface and continuous anteriorly with the cornea. The stroma is banded by loose connective tissue, the lamina fusca internally and episclera externally.

sclera inflammation

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 (

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.

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References in periodicals archive ?
The aim of this research was to describe morphometric aspects of healthy right and left eyeballs from wild, adult, male and female common kestrels (Falco tinnunculus) and to measure the thickness of their cornea, retina, choroid, and sclera.
The app then calculates the color information from the sclera -- based on the wavelengths of light that are being reflected and absorbed -- and correlates it with bilirubin levels using machine learning algorithms.
The animals within each set were identical except for the eyes, which varied with respect to the size, colour and presence of sclera.
Therefore adjunct treatment aims at inhibiting the fibroblast proliferation or covering the bare sclera with a tissue of similar properties.
Coverage also includes understanding and treating refractive, eye movement, and alignment disorders, and disorders of the cornea, conjunctiva, sclera, iris, pupil, macula, optic nerve, retina, vitreous, and uvea, such as cataracts, conjunctivitis, pink eye, macular degeneration, uveitis, iritis, vitreous detachment, floaters, and glaucoma, and eyeglasses and contact lenses, LASIK and LASEK surgery, photorefractive keratectomy surgery, and phakic intraocular lenses.
Alcaptonuria (black urine disease) is a rare inherited genetic disorder of phenylalanine and tyrosine metabolism with hiperpigmentation of skin, sclera, cartilages, degenerative ochronic arthropathies.
We had talked about how fortunate we were to have what we have, so we wanted to do something different," Kathleen Sclera said.
2) London-based architect--and winner of the fair's Designer of the Year Award-David Adjaye built Genesis, an outdoor pavilion made from timber that was similar to his Sclera structure erected for the 2008 London Design Festival.
All four patients with ocular rosacea and SIBO reported marked improvement in conjunctivitis, sclera erythema, and dry eyes following treatment with rifaximin," Dr.
The inflamed sclera has a 'violaceous hue' when viewed in natural light with injection of the deeper, larger blood vessels.
Redness occurs when the blood vessels in the white of the eye - sclera - expand.
Bloodshot eyes occur when the small blood vessels of the usually transparent conjunctiva membrane on the surface of the eye become enlarged and congested with blood, giving a red tint to the underlying sclera, the "white" of the eyes.