A 74-year-old male patient, who previously had central corneal opacity, presented to our clinic with decrease in vision, and diffuse corneal edema following uncomplicated phacoemulsification and intraocular lens implantation. With topical treatment of steroids and artificial tears, the edema resolved in peripheral cornea and remained edematous in the central cornea during the following 2.5 months. Optical coherence tomography showed Descemet membrane detachment (DMD) in the edematous area. Intracameral perfluoropropane (C3F8) was injected. In the following days, Descemet membrane reattached and corneal edema resolved. The visual acuity increased to 20/40. Following uneventful phacoemulsification, if corneal edema is refractory to treatment, DMD should be remembered. In cases where corneal opacity interferes with the detailed examination of cornea, optical coherence tomography is helpful. In those patients, C3F8 injection is a viable option even in the late post-operative weeks.