This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Diagnosis and Treatment of Retina, Subject name: Ophthalmology
[{'content': 'Gas used in retinal temponade- \nSelect and explain. \nA. SF6, B. Ethylene oxide, C. Nitrous oxide, D. CO2', 'role': 'user'}, {'content': 'Answer: A \nExplanation: SF6 Pars plana vitrectomy (PPV) with gas tamponade is widely popular for the treatment of rhegmatogenous retinal detachment . Four different intraocular gases are commonly used in vitreoretinal surgery: air, sulfur hexafluoride (SF6), perfluoroethane (C2F6) and perfluoropropane (C3F8). Indications for tamponades- To drain subretinal hemorrhages/fluid To provide internal tamponade of retinal breaks in postoperative cases', 'role': 'assistant'}]