The term Sclera is derived from the Greek word sclerosis meaning “hard”. It is an opaque , elastic and resistant fabric of the eye. It can be compared to an incomplete shell comprising approximately 90% (five sixths) of the outer layer of the eye. The anterior part starts in the limbus and ends in the posterior optic nerve canal. The primary function of the sclera is to protect the eye and maintain the shape of the eyeball.
Sclera is the part of the eye known as the “white”, where the support wall of the eyeball is formed, which is continuous with the transparent cornea. The conjunctiva is covered by a clear mucous membrane that helps lubricate the eye being thicker in the area surrounding the optic nerve. This is composed of three divisions:
The episclerotic: connective tissue lax, located below the conjunctiva.
Proper sclerotic: dense white tissue that gives you the area of your color.
The lumina fusca: It is the innermost zone composed of elastic fibers.
There are a number of abnormalities associated with the sclera, in which some are genetic and include:
Melanosis: Excess melanin deposits, which can swell, notch and have a bulge on the surface of the sclera.
Ectasia: It manifests as a thinning and swelling of the sclera that can be produced as a secondary effect of trauma or inflammation.
The treatment for these anomalies are not available or are impractical
The sclera is a firm fibrous membrane that maintains the shape of the eye as an approximately balloon shape, which is much thicker towards the posterior back side of the eye than towards the anterior front of the eye.
The white sclera continues around the eye, which in the majority is not visible while the eyeball is in its socket (inside the face and skull). The main area of the eye that is not covered is the front part as it is protected by the transparent cornea in place.
The structure of the sclera
The sclera is composed of white fibrous tissue interspersed with fibers and corpuscles of fine elastic flattened connective tissue. These fibers are grouped into bundles. The supply of blood to the sclera is made through small (but not very numerous) capillary interconnections.