One day after pars plana vitrectomy with membrane peel and 20% SF6 gas-air exchange, a patient reports blurred vision. Intraocular pressure is 42 mmHg. The most likely explanation is:

• A Steroid response from postoperative drops
• B Silicone oil overfill from a prior procedure
• C Malignant glaucoma from anterior rotation of the ciliary body
• D Expansion of the intraocular gas, since SF6 expands to about twice its injected volume ✓

Explanation

Pure SF6 expands approximately twofold and C3F8 approximately fourfold before dissolving, so peak expansion occurs within the first 24 to 72 hours and commonly raises intraocular pressure. Management includes aqueous suppressants and, if needed, gas removal. Steroid responses typically appear after 1 to 2 weeks, and malignant glaucoma presents with a shallow anterior chamber rather than isolated pressure rise.

Reference: Kanski's Clinical Ophthalmology, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.