PURPOSE: To describe severe acute corneal hydrops in a patient with previously undiagnosed keratoconus, in which anterior segment optical coherence tomography (AS-OCT) revealed a protruding ridge of tissue on either side of Descemet membrane (DM) break, treated successfully with ultrathin Descemet-stripping automated endothelial keratoplasty (UT-DSAEK). METHODS: A case report. RESULTS: A 32-year-old man presented with severe corneal hydrops in OS. He was treated conservatively with hypertonic saline. Serial AS-OCT revealed persistent edema and haze overlying a break in DM, with a ridge of protruding tissue on either side. Based on these findings, UT-DSAEK was performed. Intraoperatively, the ridge of tissue remained firmly adhered after DM removal and was felt to possibly represent posterior stroma. The patient's uncorrected visual acuity improved to 20/80. Literature review revealed 1 case with similar AS-OCT findings who underwent penetrating keratoplasty; histopathology was reported to show Descemet scrolls on either side of the break, but our analysis of this and other reports suggest that an additional layer of tissue is contained within the scroll along with DM. CONCLUSIONS: This case demonstrates severe corneal hydrops in the setting of keratoconus, in which AS-OCT revealed a ridge of protruding tissue on either side of a break in DM. UT-DSAEK led to resolution of corneal edema and improvement in stromal haze and visual acuity. Further research is required to determine the precise role of endothelial keratoplasty and potential role of posterior stromal rupture in some cases of acute corneal hydrops.