LASIK interface complications: what is the appropriate term for PISK?

To the Editor: We read with great interest the article “LASIK Interface Complications: Etiology, Management, and Outcomes” by Randleman and Shah.1 We agree completely with the authors when they stated: “Clarifying the nomenclature used for each entity is critical to enhancing future communication.” It is especially important in the most rare conditions, including the one they called “pressureinduced stromal keratopathy (PISK)” as Tourtas and Cursiefen2 suggested. It is true that in the early postoperative period of LASIK, corneal edema that might lead to accumulation of fluid in the interface or to interface and stromal haziness is almost invariably secondary to high intraocular pressure (IOP) as result of steroid response. But it does not mean that the ocular hypertension is the ultimate cause of the condition. It has been shown both experimentally and in the clinical setting that corneal edema not related to topical steroids may cause the accumulation of fluid. In an elegant ex vivo experimental study, Dawson et al. demonstrated that both endothelial cell damage and high IOP may cause swelling of the LASIK interface.3 In a recent report, a 37-year-old man underwent a bioptics procedure in which a corneal fl ap was created with a mechanical microkeratome followed by the implantation of an angle-supported foldable anterior chamber. He presented 43 months after surgery with interface fl uid accumulation in the right eye related not to topical steroids or ocular hypertension but to endothelial dysfunction and subsequent corneal edema.4 We recently suggested a new term based on pathophysiology of the condition.5 Because the primary causative factor is edema, not IOP, we think that an appropriate term for the condition has to exclude the words “pressure-induced.” We proposed the term “post-LASIK edema-induced keratopathy (PLEK).” It may be applied to the whole spectrum of the condition, with or without apparent interface fluid, and related or not to ocular hypertension. Because the number of post-LASIK patients undergoing phacoemulsification will increase progressively, undoubtedly we will see more frequently PLEK cases related to endothelial dysfunction and not related to either acute steroid response or high IOP of other causes.6