Obstruction of the lacrimal drainage system.

This review covers evolving concepts in lacrimal outflow obstruction. Recent studies have increased our understanding of the surgical anatomy and pathophysiology of the lacrimal drainage system through radiologic, clinical, and microbiologic techniques. While external dacryocystorhinostomy remains an important treatment for nasolacrimal duct obstruction, there have been a number of therapeutic developments worthy of review, including advances in endoscopic and transcanalicular dacryocystorhinostomy, conjunctivodacryocystorhinostomy, and the use of mitomycin C in these procedures. In addition, we summarize recent advances in minimally invasive techniques for lacrimal outflow obstruction, including balloon dacryocystoplasty, lacrimal stents, and conjunctivoplasty. Finally, the roles of probing versus irrigation, nasal endoscopy, and endoscopic dacryocystorhinostomy in children are discussed.