Penetrating keratoplastyKeratoplasty à chaud is contraindicated in acute keratoconus. In the past the stromal scarringScarring was waited for 3–6 months with the administration of hyperosmolar eyeEye drops. Today, after a prophylactic YAG-iridotomy caudally through the still clear corneaCornea, air is injected into the anterior chamber and multiple deep stromal 10–0 nylon single compression suturesCompression sutures are placed perpendicular to the Descemet tear. Already on the first day postoperatively the corneaCornea is typically much clearer. The histological analysis shows a significantly smaller distance between the ends of the Descemet tear in the range of 100 µm after so-called Muraine suturesMuraine sutures compared to more than 1000 µm in the spontaneous course.