Staphyloma
A staphyloma is an abnormal protrusion of the uveal tissue through a weak point in the eyeball. The protrusion is generally black in colour, due to the inner layers of the eye. It occurs due to weakening of outer layer of eye by an inflammatory or degenerative condition.
It may be of five types, depending on the location on the eyeball.
Anterior (corneal) staphyloma
In the anterior segment of the eye, involving the cornea and the nearby sclera. It is an ectasia and outpouching of the pseudocornea which results after total sloughing of cornea in sloughening corneal ulcer with iris plastered behind; the pseudocornea, being too weak to resist the IOP protrudes forward with the uveal tissue. This is known as anterior staphyloma.Intercalary staphyloma
It is the name given to the localised bulge in limbal area, lined by the root of the iris. It results due to ectasia of weak scar tissue formed at the limbus, following healing of a perforating injury or a peripheral corneal ulcer. There may be associated secondary angle closure glaucoma, may cause progression of the bulge if not treated. Defective vision occurs due to marked corneal astigmatism. Treatment consists of localised staphylectomy under heavy doses of oral steroids.Ciliary staphyloma
As the name implies, it is the bulge of weak sclera lined by ciliary body, which occurs about 2–3 mm away from the limbus. Its common causes are thinning of sclera following perforating injury, scleritis & absolute glaucoma.It is a part of anterior staphyloma.