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
Keyhole-shaped visual field defect is seen in lesion involving which of the following regions? 
Select and explain. 
A. Optic disk, B. Optic chiasma, C. Lateral geniculate body, D. Occipital lobe
C: Lateral geniculate body
Answer: C: Lateral geniculate body 
Explanation: Ans: C. Lateral geniculate body(Ref Walsh and Hoyt; Clinical Neuro-Ophthalmology 6/e p122)Key-hole shaped visual field defects are typically seen in the lesions involving lateral geniculate body but keyhole shaped defect (not visual field defect) is seen in the coloboma of Iris.