After pars plana vitrectomy, a patient is kept prone for 1 week. The tamponade agent used was most likely:
- A Silicone oil 1000 centistokes
- B Expansile gas (SF6 or C3F8) ✓
- C Perfluorocarbon liquid
- D Balanced salt solution
Correct answer: B. Expansile gas (SF6 or C3F8)
Explanation
Gases (SF6, C3F8) are lighter than vitreous and exert upward tamponade; for superior retinal breaks the patient maintains face-up or head positions, but for inferior or posterior breaks the patient must be prone so the gas bubble rises to tamponade the break. Gas absorbs over days to weeks (SF6 ~10–14 days, C3F8 ~6–8 weeks) requiring sustained posturing. Silicone oil is a long-term tamponade agent not requiring strict prolonged posturing post-operatively as it stays in place. PFCL is removed intraoperatively.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.