Dacryostenosis is a term denoting the obstruction of the nasolacrimal duct, which may be either congenital or acquired, depending on the etiology. Epiphora is the most important symptom and may be accompanied by a range of ocular disturbances. The diagnosis is made after a detailed clinical assessment and fluorescein dye application on the affected eye, whereas imaging studies are necessary for future steps in therapy.
Obstruction of the nasolacrimal duct is known as dacryostenosis, and two major subtypes exist - congenital and acquired   . In newborns, the condition stems from both embryological (incomplete canalization) or mechanical (displacement of the cranial structures situated in the area where the nasolacrimal apparatus is located) events during embryonal life, childbirth or in the postpartum period  . The majority of acquired cases, on the other hand, are seen in adults over 50 years of age, with many diagnoses being idiopathic, but tumors, surgical procedures, trauma, and sarcoidosis have been reported as possible causes . The most prominent symptom of dacryostenosis is epiphora (increased watering of the eye) that may be persistent and followed by mucopurulent discharge  . Visual blurring, as well as driving and reading difficulties, are reported in adults . Despite the fact that 20-70% of neonates present with epiphora that strongly suggests dacryostenosis, a complete resolution is seen in up to 96% of cases by the first year of life, but if the problem persists, or is undiagnosed, several complications can arise . Secondary infections (conjunctivitis, dacryocystitis or orbital cellulitis), unequal refractive power (anisometropia) as the affected eye may develop refractive error, or the formation of a dacryocystocele, which will obstruct the nasal passage of air and cause respiratory difficulties    .
A detailed physical examination and a properly obtained patient history obtained from the parents in the setting of congenital dacryostenosis are vital components of the workup. A history of excessive watering or discharge from the eye shortly after birth must raise clinical suspicion toward this condition, especially if they are confirmed during the exam  . One of the simplest and fastest methods for confirming nasolacrimal duct obstruction is the fluorescein dye test, during which fluorescein-stained saline is applied onto the affected eye  . The dye should ideally disappear from the tear film after 5 minutes. If it is retained in a thickened tear strip then it indicates dacryostenosis. Although the diagnosis can be confirmed in virtually all cases by this method, the role of imaging studies is still important, primarily for therapeutic planning if the condition does not resolve spontaneously. Computed tomography (CT), particularly the single-photon emission computed tomography (SPECT), magnetic resonance imaging (MRI) and ultrasonography (US) have all been recommended when it comes to imaging assessment of the nasolacrimal duct and adjacent structures   . Furthermore, dacryoscintigraphy and dacryocystography have also been described as useful diagnostic methods . Ultrasonography, however, is the most convenient diagnostic method in newborns and children, while more advanced studies are performed if the initial findings are inconclusive .