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
In which of the following conditions Berlin's edema is 
Select and explain. 
A. Open angle glaucoma, B. After cataract surgery, C. After concussional trauma, D. Diabetic retinopathy
C: After concussional trauma
Answer: C: After concussional trauma 
Explanation: C i.e. After concussion trauma Blunt trauma to eye may produce Berlin's edema or commotio retinae Q which is a cloudy swelling characterized by a grey appaerance, most frequently in the temporal region. It may also manifest as cherry red spot in the foveal region.