This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Ophthalmology
Peripheral iridectomy is must in which of the following? 
Select and explain. 
A. Primary open-angle glaucoma, B. Absolute glaucoma, C. Closed-angle glaucoma, D. Cataract
C: Closed-angle glaucoma
Answer: C: Closed-angle glaucoma 
Explanation: .