Sclera

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The sclera (plural: scleras or sclerae) is the fibrous, opaque white, coat of the eye. It functions to protect the ~~intra-ocular~~intraocular contents.

Summary

location: posterior fifth-sixths of the eyeball
blood supply: ciliary arteries
innervation: ciliary nerves
relations: anteriorly continuous with the cornea

Gross anatomy

Outermost coat of the 3-layered globe. Anteriorly continuous with the cornea. Posteriorly perforated by the optic nerve at the lamina cribrosa.

Arterial supply

Anteriorly, the anterior ciliary arteries form a dense episcleral plexus. Posteriorly, supplied by branches of the short and long posterior ciliary arteries.

Lymphatic drainage

The sclera is an alymphatic organ.

Innervation

Anteriorly supplied by the long ciliary nerves. Posteriorly supplied by the short ciliary nerves.

Histology

The sclera may be divided into its three histological layers:

episclera
- outermost, loose connective tissue layer, connected to the Tenon's capsule
- rich vascular supply from anterior ciliary arteries
scleral stroma
- dense fibrous tissue intermingled with fine elastic fibers
- irregular arrangement of type I and III collagen responsible for its opacity
lamina fusca
- innermost layer with melanocytes
- weakly related to the choroid

Radiographic features

Ultrasound and CT are not useful modalities.

Anterior segment ocular coherence tomography (AS-OCT)

readily used in clinical practice to measure sclera thickness, monitor therapeutic response in scleritis treatment
quantitative measurements obtained

MRI

useful in the diagnosis of posterior scleritis and episcleritis
T1-weighted sequences, sclera appears as the hypointense rim of the globe

History and etymology

~~Medical~~The word derives from medical Latin, itself from the Greek sklera ~~(menix)~~"the hard (membrane)," ~~fem.~~feminine form of skleros"hard".

Related pathology

scleral plaques
episcleritis/scleritis: inflammation of the sclera
staphyloma: full or partial thickness sclera defect lined by uvea

-<p>The <strong>sclera</strong> (plural: scleras or sclerae) is the fibrous, opaque white, coat of the <a href="/articles/ocular-globe-1">eye</a>. It functions to protect the intra-ocular contents. </p><h4>Summary</h4><ul>
+<p>The <strong>sclera</strong> (plural: scleras or sclerae) is the fibrous, opaque white, coat of the <a href="/articles/ocular-globe-1">eye</a>. It functions to protect the intraocular contents. </p><h4>Summary</h4><ul>
-</ul><h4>Gross anatomy</h4><p>Outermost coat of the 3-layered <a href="/articles/globe-1">globe</a>. Anteriorly continuous with the cornea. Posteriorly perforated by the <a href="/articles/optic-nerve">optic nerve</a> at the <a href="/articles/cribriform-plate">lamina cribrosa</a>. </p><h4>Arterial supply</h4><p>Anteriorly, the anterior ciliary arteries form a dense episcleral plexus. Posteriorly, supplied by branches of the short and long posterior ciliary arteries. </p><h4>Lymphatic drainage</h4><p>The sclera is an alymphatic organ.</p><h4>Innervation</h4><p>Anteriorly supplied by the <a href="/articles/long-ciliary-nerves">long ciliary nerves</a>. Posteriorly supplied by the <a href="/articles/short-ciliary-nerves">short ciliary nerves</a>. </p><h4>Histology</h4><p>The sclera may be divided into its three histological layers:</p><ol>
+</ul><h4>Gross anatomy</h4><p>Outermost coat of the 3-layered <a href="/articles/ocular-globe-1">globe</a>. Anteriorly continuous with the cornea. Posteriorly perforated by the <a href="/articles/optic-nerve">optic nerve</a> at the <a href="/articles/lamina-cribrosa-sclerae">lamina cribrosa</a>. </p><h4>Arterial supply</h4><p>Anteriorly, the <a title="Anterior ciliary artery" href="/articles/anterior-ciliary-artery">anterior ciliary arteries</a> form a dense episcleral plexus. Posteriorly, supplied by branches of the short and long <a title="Posterior ciliary artery" href="/articles/posterior-ciliary-artery">posterior ciliary arteries</a>. </p><h4>Lymphatic drainage</h4><p>The sclera is an alymphatic organ.</p><h4>Innervation</h4><p>Anteriorly supplied by the <a href="/articles/long-ciliary-nerves">long ciliary nerves</a>. Posteriorly supplied by the <a href="/articles/short-ciliary-nerves">short ciliary nerves</a>. </p><h4>Histology</h4><p>The sclera may be divided into its three histological layers:</p><ol>
~~-</ul><h4>History and etymology</h4><p>Medical Latin, from Greek <em>sklera (menix)</em> "the hard (membrane)," fem. of <em>skleros</em> "hard".</p><h4>Related pathology</h4><ul>~~
+</ul><h4>History and etymology</h4><p>The word derives from medical Latin, itself from the Greek sklera "the hard (membrane)," feminine form of skleros "hard".</p><h4>Related pathology</h4><ul>