Gas Expansion Three Days after Pars Plana Vitrectomy with Sulfur Hexafluoride 20% Tamponade following Carbon Monoxide Toxicity and Oxygen Therapy

PURPOSE: To report an unusual case of gas expansion following oxygen therapy in a patient with sulfur hexafluoride (SF(6)) 20% tamponade after pars plana vitrectomy. Case Report. A 40-year-old man came to the clinic with severe ocular pain and redness and also vision decrease in his left eye three days after uncomplicated 23-gauge pars plana vitrectomy, internal limiting membrane peeling combined with phacoemulsification, and using 20% SF(6) injection as a tamponade agent due to significant cataract and a full-thickness macular hole. In ophthalmic examinations of his left eye, high intraocular pressure (approximately 70 mmHg), a flat anterior chamber, and a gas-filled vitreous cavity were found. The patient had been hospitalized the day before due to carbon monoxide poisoning and had undergone oxygen therapy with a pure 100% mask for three hours. CONCLUSION: It seems that oxygen therapy or carbon monoxide poisoning increases the volume of gas in the patient's vitreous cavity and the nonexpansile percentage of SF(6) expands.