Interface Fluid Syndrome (IFS) following Toxic Anterior Segment Syndrome (TASS): not related to high intraocular pressure but to endothelial failure

Abstract

We describe the case of a 52-year-old female with past history of LASIK, 21\u202fyears earlier, without Fuchs’ endothelial dystrophy, who underwent phacoemulsification and intraocular lens (IOL) implantation. During the early postoperative period severe corneal edema, anterior chamber cellularity and iris inflammation presented, accompanied by a clear space along the LASIK interface. Those findings were interpreted as part of a Toxic Anterior Segment Syndrome (TASS) and secondary interface fluid syndrome (IFS). When interface fluid was present, intraocular pressure (IOP) measured in the center of the cornea yielded very low values. In addition, applanation tonometry performed in the corneal periphery, as well as Schiotz tonometry and digital tonometry also indicated that the IOP was not high. Fluid in the interface persisted until a DMEK was carried out 11\u202fmonths after the phacoemulsification surgery. Five days postoperatively the IFS resolved, confirmed by OCT imaging. The origin of IFS in this case was corneal edema secondary to endothelial cell dysfunction and it was not related to high IOP. This is the first reported case of IFS following TASS, the third case published of DMEK procedure used to solve endothelial failure-related IFS, and the case with the longest time of presentation after LASIK.