This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cornea and sclera, Subject name: Ophthalmology
Most common cause of posterior staphyloma 
Select and explain. 
A. Trauma, B. Glaucoma, C. Myopia, D. Scleritis
C: Myopia
Answer: C: Myopia 
Explanation: POSTERIOR STAPHYLOMA It effects the posterior pole of the eye and is lined by the choroid. Degenerative high axial myopia is the most common cause. Indirect ophthalmoscopy shows a posterior outward curvature of the globe detected as a crescentric shadow in the macular region. The retinal vessels are seen to change direction, dipping down into the region. The staphylomatous region may appear pale due to degenerative changes in the retina, retinal pigment epithelium and choroid. Ref:- Parsons diseases of eye; pg num:-230