We report the use of perfluoropropane (C3F8) gas for the treatment of acute hydrops with intrastromal cleft in a case of pellucid marginal degeneration with keratoglobus. Acute hydrops in a 36-year-old man with pellucid marginal degeneration with keratoglobus was treated with intracameral injection of 0.3 mL isoexpansile C3F8 (14%). Reduction in corneal haze was seen beginning from the third postoperative day. Significant clearing had taken place by the end of the second week with the closure of intrastromal cleft. Best corrected visual acuity improved from finger counting at 1 foot preoperatively to 6/18 after 2 weeks. There was no postoperative rise in intraocular pressure or cataract formation. Intracameral injection of C3F8 may possibly be a viable treatment option for acute hydrops in a case of corneal ectasia. Larger studies are required to clarify the role of intracameral gas injection in the treatment of acute hydrops in corneal ectasia.