Commonest cause of posterior staphyloma:
Ans. D: High myopia Degenerative high axial myopia is the most common cause of posterior staphyloma Staphyloma It 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 (cornea or sclera) by an inflammatory or degenerative condition. It may be of 5 types, depending on the location on the eye ball (bulbus oculi). Anterior (corneal) staphyloma In the anterior segment of the eye, involving the cornea and the nearby sclera. 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 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 and absolute glaucoma. Equatorial staphyloma Seen on the equator of the eye (region circumferencing the largest diameter ohogonal to the visual axis). Its causes are scleritis and degeneration of sclera in pathological myopia. It occurs more commonly in the regions of sclera which are perforated by voex veins. Posterior staphyloma It is seen in the posterior segment of the eye, typically diagnosed at the region of the macula, deforming the eye in a way that the eye-length is extended associated with myopia (nearsightedness). It is diagnosed by ophthalmoscopy, which shows an area of retinal excavation in the region of the staphvloma
Glaucoma
Retinal detachment
Iridocyclitis
High myopia