Posterior staphyloma, most common cause –
Staphyloma
Staphyloma is an abnormal protrusion of uveal tissue through a weak and thin portion of cornea or sclera
 
So, a staphyloma is lined internally by uveal tissue and externally by weak cornea or sclera.
o Staphyloma is divided anatomically into : -
 
Anterior staphyloma: - Protrusion and adhesion ofiris to ectatic cornea. The most common cause is a sloughing corneal ulcer which perforates and heals with the formation of pseudocornea by the organization of exudates and laying down of fibrous tissue. It is lined internally by iris.
 
Intercalary staphyloma: - It occurs at the limbus. It islined internally by the root of iris and the anterior most portion of the ciliary body. The causes are perforating injuries to limbus, marginal corneal ulcer, anterior scterilis, Scleromalacia perforans, Complicated cataract surgery, secondary angle closure glaucoma.
 
Ciliary staphyloma : This affects the ciliary zone thatincludes the region upto 8 mm behind the limbus. The ciliary body is incarcerated in the region of scleral ectasia. Causes arc Developmental glaucoma. Primary or secondary glaucoma end stage, scleritis, trauma to ciliary region.
 
Equatorial staphyloma : - This occurs at theequatorial region of the eye with incarceration of the choroid.
 
Causes are scleritis, degenerative myopia and chronic uncontrolled glaucoma.
Posterior staphyloma : - Occurs at posterior pole andis lined internally by choroid. Degenerative high axial myopia is the most common cause.
Trauma
Myopia
Iridocyclitis
Glaucoma