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
Field defect seen in pituitary adenoma is - 
Select and explain. 
A. Bitemporal hemianopia, B. Binasal hemianopia, C. Quadrantanopia, D. "Pie in sky" defect
A: Bitemporal hemianopia
Answer: A: Bitemporal hemianopia 
Explanation: The characteristic visual field defect in pituitary adenoma is bitemporal hemianopia due to central optic chiasma lesion. However in early stages qudrantanopia (superior: - Pie in sky or inferior: Pie on the floor) may also occur, but these are not characteristics.