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
Coloured halo is seen in all except: 
Select and explain. 
A. Open angle glaucoma, B. Closed angle glaucoma, C. Cataract, D. Any of the above
A: Open angle glaucoma
Answer: A: Open angle glaucoma 
Explanation: A i.e. Open angle glaucoma