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
Gas used in retinal temponade- 
Select and explain. 
A. SF6, B. Ethylene oxide, C. Nitrous oxide, D. CO2
A: SF6
Answer: A: SF6 
Explanation: 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