This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Ophthalmology
Bitemporal hemianopic visual field defect is characteristic feature in which of the following condition? 
Select and explain. 
A. Glaucoma, B. Optic neuritis, C. Pituitary tumour, D. Retinal detachment
C: Pituitary tumour
Answer: C: Pituitary tumour 
Explanation: Bitemporal hemianopia is a visual field defect that is usually due to chiasmatic disease such as a pituitary tumor growing up out of the sella turcica and pressing on the underside of the chiasm. The most common cause of bitemporal hemianopia is a pituitary adenoma, occasionally it results from other parasellar or suprasellar lesions such as meningioma, and craniopharyngioma. Lesions encroaching the optic chiasma from above tend to cause inferior temporal defects initially. The defect will be first and worst in the upper quadrants with infra chiasmatic masses. With suprachiasmatic masses the defect will be first and worst in lower quadrants. Ref: DeJong's The Neurologic Examination By William W. Campbell page 165.