Sclera
Sensory (eye & ear)OrgansHeadLeft and right
View left in 3D View right in 3D
- What it is
- The tough white outer coat of the eyeball, made of dense interwoven collagen. It covers the posterior five-sixths of the globe and is continuous in front with the cornea at the limbus and behind with the dural sheath of the optic nerve.
- Function
- Protects the eye and keeps its shape against the intraocular pressure; the six extraocular muscles pull on it.
- Size
- Globe 24 mm in diameter; sclera about 1 mm thick at the back, thinnest (0.3 mm) just behind the rectus insertions; anterior opening ~11-12 mm wide.
- Clinical note
- A bluish sclera is seen in osteogenesis imperfecta (thin collagen lets the choroid show through); a yellow sclera is the first sign of jaundice.