Pseudoexfoliation Syndrome and Glaucoma

Abstract

Pseudoexfoliation (PEX) syndrome is a generalized disorder of the extracellular matrix, which can be characterized as a stress-induced elastosis associated with the excessive production and abnormal aggregation of elastic fiber components in intra- and extraocular tissues. It is a major cause of severe open-angle glaucoma, which accounts for 20–25% of all open-angle glaucomas worldwide and currently represents the most common identifiable cause of glaucoma overall. The characteristic tissue alterations also predispose to a broad spectrum of intraocular complications, including phacodonesis and lens subluxation, angle-closure glaucoma, pigment dispersion, insufficient mydriasis, blood–aqueous barrier dysfunction, posterior synechiae, as well as corneal endothelial decompensation. PEX syndrome has been also shown to be a systemic process, which appears to be associated with increased cardiovascular and cerebrovascular morbidity. Single-nucleotide polymorphisms in exon 1 of the lysyl oxidase-like 1 (LOXL1) gene have been recently identified as strong genetic risk factors for both PEX syndrome and PEX glaucoma. LOXL1 is a pivotal cross-linking enzyme in elastogenesis and seems to be involved in abnormal PEX fiber formation and aggregation.