Congenital nasolacrimal duct obstruction from an ophthalmologist's point of view. Causes, diagnosis and staged therapeutic concept

Congenital nasolacrimal duct obstruction (CNLDO) is one of the most frequent issues in pediatric ophthalmology. There are different therapeutic options, including conservative treatments as well as surgical interventions. These strategies can be classified using a staged therapeutic concept. What are the therapeutic strategies for CNLDO from an ophthalmologist's point of view? In this review, different kinds of CNLDO are described. Existing therapeutic interventions are dedicated to the different forms of CNLDO and summarized in a staged therapeutic concept. CNLDO is not a homogeneous disease. Different and also combined pathologies exist. According to symptoms and localization of stenosis, different therapeutic interventions are available. The most common CNLDO manifestation is a persistent Hasner's membrane. If conservative approaches have failed, pressurized probing and syringing of the nasolacrimal duct is the method of choice. This can usually be done under local anesthesia. Since some children show persisting symptoms, other therapies (probing and syringing under general anesthesia with nasolacrimal duct intubation, external dacryocystorhinostomy) have to be considered. Here, dacryoendoscopy offers additional diagnostic and therapeutic options. The precise classification of CNLDO and knowledge concerning possible therapeutic interventions are essential. Due to ongoing development of surgical approaches, an increasingly individualized therapy is possible. A gradual therapeutic regimen is available for CNLDO, which has to be adapted individually.