This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neuro-ophthalmology, Subject name: Ophthalmology
Optic neuritis causes - 
Select and explain. 
A. Gradual painless loss of vision, B. Sudden painless loss of vision, C. Gradual painful loss of vision, D. Sudden painful loss of vision
D: Sudden painful loss of vision
Answer: D: Sudden painful loss of vision 
Explanation: Visual loss in optic neuritis : Sudden, progressive and profound visual loss. Patients may complain of dull eye ache. Ref:AK Khurana 6thE pg 318