The sclera is the part of the eye commonly known as the “white.” It forms the supporting wall of the eyeball, and is continuous with the clear cornea.
The sclera is covered by the conjunctiva, a clear mucus membrane that helps lubricate the eye. It is thickest in the area surrounding the optic nerve. The sclera is made up of three divisions: the episclera, loose connective tissue, immediately beneath the conjunctiva; sclera proper, the dense white tissue that gives the area its color; and the lamina fusca, the innermost zone made up of elastic fibers.
There are a number of abnormalities associated with the sclera. Some are genetic and include:
- Melanosis: excess deposits of melanin (pigment) on the surface of the sclera, which can become inflamed and uncomfortable
- Scleral Coloboma: missing tissue that results in notching and bulging of the sclera (lesions)
- Ectasia: a thinning and bulging of the sclera
There are now state-of-the-art contact lenses that are fitted to treat those with scleral ectasia.
Acquired abnormalities of the sclera include:
- Ectasia that can be brought on as a side effect of traumas or inflammations
Episcleritis: a hypersensitivity reaction which can be anterior or posterior, is characterized by engorged blood vessels, and can also affect the cornea