This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ocular Trauma, Subject name: Ophthalmology
[{'content': "Berlin's edema is due to - \nSelect and explain. \nA. Blunt trauma to eye, B. Extradural hemorrhage, C. Choroidal melanoma, D. Parsplanitis", 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Blunt trauma to eye o Berlin's edema (commotio retinae) is a common condition caused by blunt injury to the eye. It is characterized by decreased vision in the injured eye a few hours after the injury. Under examination the retina appears opaque and white in colour in the periphery but the blood vessels are normally seen. Cherry-red' spot in the foveal region may be seen.", 'role': 'assistant'}]