Citation, DOI and article data
The sclera (plural: scleras or sclerae) is the fibrous, opaque white, coat of the eye. It functions to protect the intraocular contents.
- location: posterior fifth-sixths of the eyeball
- blood supply: ciliary arteries
- innervation: ciliary nerves
- relations: anteriorly continuous with the cornea
- anteriorly, the anterior ciliary arteries form a dense episcleral plexus
- posteriorly, supplied by branches of the short and long posterior ciliary arteries
The sclera is an alymphatic organ.
The sclera may be divided into three histological layers:
- outermost, loose connective tissue layer, connected to the Tenon 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
Ultrasound and CT are not useful modalities.
Anterior segment ocular coherence tomography (AS-OCT)
- readily used in clinical practice to measure scleral thickness, monitor therapeutic response in scleritis treatment
- quantitative measurements obtained
- useful in the diagnosis of posterior scleritis and episcleritis
- T1-weighted sequences, sclera appears as the hypointense rim of the globe
History and etymology
The word derives from medical Latin, itself from the Greek sklera "the hard (membrane)," feminine form of skleros "hard".
- 1. Richard S. Snell, Michael A. Lemp. Clinical Anatomy of the Eye. (2013) ISBN: 9781118691007