sclerotic

sclerotic /scle·rot·ic/ (sklĕ-rot´ik)

1. hard or hardening; affected with sclerosis.

2. scleral.

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scle·rot·ic (skl-rtk)

adj.

1. Affected or marked by sclerosis.

2. Of or relating to the sclera of the eye.

n. or scle·rot·i·ca (-rt-k)

See sclera.

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sclerotic

[sklirot′ik]

Etymology: Gk, skleros, hard

pertaining to induration or hardening.

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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 sclera