Arrange the following tamponade agents in decreasing order of intraocular residence time after complete fluid-air exchange: air, SF6, C2F6, C3F8. Which agent provides the longest duration of internal tamponade?
- A SF6
- B C3F8 ✓
- C C2F6
- D Air
Correct answer: B. C3F8
Explanation
Residence time depends on molecular weight and diffusivity. Air lasts roughly 5 to 7 days, SF6 about 10 to 14 days, C2F6 approximately 4 weeks, and C3F8 the longest at 6 to 8 weeks. This is why C3F8 is selected when prolonged tamponade is needed, such as giant tears or inferior breaks in patients who cannot posture. The tempting distractor C2F6 is longer lasting than SF6 but still shorter than C3F8 by several weeks.
Reference: Ryan's Retina, 6th ed.
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Written and medically reviewed by the StethoPrep medical team.