A 73-year-old woman with a corneal perforation of undetermined etiology was treated with corneal patch grafting. A residual partial-thickness corneal button obtained during a previous Descemet stripping automated endothelial keratoplasty (DSAEK) surgery and stored at -80°C in Optisol GS for 3 months was used as a patch graft. Five days postoperatively, the anterior chamber was reformed and the perforation was masked by the donor cornea. During the next several weeks, gradual displacement of the anterior edge of the donor cornea in the limbal direction occurred. Seven weeks postoperatively, further displacement of the donor cornea resulted in unmasking of the perforated area. At this time, the corneal defect was closed by stromal scar tissue and corneal epithelium. Five months postoperatively, best corrected visual acuity was 1.0 without marked astigmatism and intraocular pressure was 9 mm Hg in the left eye. From this case, we learned that cryopreserved DSAEK flaps stored longer than reported previously can be used as patch grafts to treat emergency conditions. Scar tissue can fill a corneal stromal defect 1 mm in diameter during temporary patch grafting for less than 2 months.