Early Migration of Sulfur Hexafluoride (SF6) Gas Through the Optic Nerve Head Following Silicone Oil Removal

PURPOSE: to describe an early migration of Sulfur Hexafluoride (SF6) gas through the optic nerve sheath after air/gas exchange for silicone oil removal surgery. METHODS: An 85-year-old male with glaucoma and high myopia underwent removal of 1000cS silicone oil via pars plana. Intraoperatively, we observed a localised retinal detachment which was treated with a subretinal fluid drainage under air, endophotocoagulation and sulfur hexafluoride (SF6) at the concentration of 20%. On the day after surgery, the patient had a Snellen visual acuity of 20/250, intraocular pressure of 18 mmHg, and a gas-filled vitreous chamber. RESULTS: Five days postoperatively, the patient came back with severe proptosis, palpebral edema, absent anterior chamber, and a dislocated intraocular lens, with an unexplorable fundus. Urgent CT imaging revealed SF6 gas migration into the optic nerve head sheath, compressing the nerve and causing pneumoencephalus without neurological symptoms. Urgent vitrectomy with gas removal was performed. The proptosis regressed in one week, with light perception as the final visual acuity. CONCLUSION: Early post-operative gas migration can result in severe and irreversible anatomical and functional outcomes, therefore it is required an urgent gas removal to reduce the possibility of irreversible complications. Unfortunately our case resulted in blindness in the affected eye.