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Related to sclera: conjunctiva, Blue Sclera


see eyeeye,
organ of vision and light perception. In humans the eye is of the camera type, with an iris diaphragm and variable focusing, or accommodation. Other types of eye are the simple eye, found in many invertebrates, and the compound eye, found in insects and many other
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The Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



the external tough fibrous tunic of the eye, which performs a supportive and protective function. In most vertebrates the sclera contains cartilaginous tissue and bony laminae that form a sclerotic ring. (Chondrichthians and modern amphibians and mammals do not have sclerotic rings.)

In humans the sclera consists of a dense fibrous tissue in which intermixed collagenous and elastic fibers are arranged predominantly in meridional and equatorial directions. Connective tissue cells are located between the fibers, and pigment cells (melanocytes) are found where the optic nerve leaves the eye. The external layer of the sclera contains a highly motile system of slender collagenous fibers and laminae separated from one another by slitlike cavities (Tenon’s capsule); the fibers and laminae facilitate rotation of the eyeball in various directions. The external surface of the sclera is attached to the tendons of the oculomotor muscles.

In humans the thickness of the sclera at the posterior pole of the eyeball is approximately 1 mm, at the equator approximately 0.3–0.4 mm, and at the anterior pole of the eyeball at the site of the transition into the cornea approximately 0.6 mm. Small branching cavities are found at the junction of the sclera and cornea; the cavities join to form Schlemm’s canal, which drains fluid from the anterior chamber of the eye.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


The hard outer coat of the eye, continuous with the cornea in front and with the sheath of the optic nerve behind.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.


the firm white fibrous membrane that forms the outer covering of the eyeball
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
The present study was designed to answer the following questions: Does LOX have a direct crosslinking effect on the sclera? Are the crosslinking effect of the LOX concentration and the exposure time related?
The Blood Pressure was 110/70 mmHg, he was Tachycardiac, Tachypneic and had fever (101AdegF) with jaundice (yellow) sclera. On abdominal examination hepatomegaly was found along with right hypochondriac and epigastric tenderness.
Injury to the sclera and cornea can also lead to endophthalmitis, cataracts, and retinal detachment [2].
Group II, group III, and group IV, with the exception of group I, were defined as crosslinking groups, from which right eyes were selected and subjected to sclera collagen cross-linking therapy via minimally invasive riboflavin/UVA treatment.
Unlike skin color, changes in the sclera are more consistent across all races and ethnicities.
The glaucoma drain pictured in Figure 2 shows a radial shape, befitting of the outer edge of the eye called the sclera. The thin and delicate structures of the eye require sharp puncturing tools to pierce the tissue, but softer, more compliant micromolded implants and instruments that are stable and pliable enough to move with the multiple functions of the eye.
Post-operative [beta] radiation [3] is associated with variable recurrence rates (0.5% to 33%) as well as serious complications like infections, sclera ulceration and cataract formation.
The word ochronosis refers to the dark bluish black discoloration of connective tissues including the sclera, cornea, auricular cartilage, heart valves, articular cartilage, tendons, and ligaments.
Concerning to its insertion, there is a common point located anterior to the equatorial line in direction to the sclera, of the dorsal and ventral oblique muscle.
Anterior segment ocular computerized tomography (OCT) demonstrated a thickened episclera and sclera with hyporeflective areas representing fluid in the region, confirming the diagnosis of scleritis (Figures 1(a) and 1(c)).
Thickness of the following layers was measured: ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), RPE, choroid, and sclera. Duration of the procedure was approximately 15 min per eye.