Nasolacrimal Duct Obstruction in Children
Children with a stenosis or obstruction of the nasolacrimal duct can tear and form eye boogers for a very long period (months). This is due to the fact that the normal tear drainage system is partially or not accessible at all.
Thus, instead of the tears ending up in the nose (as it should happen), they cannot move forward and turn stagnant, resulting in the tears becoming contaminated by the locally-found germs.
The most common causes of obstruction is the imperforation of a membrane (valve of Hasner), the absence of lacrimal carucles, the stenosis of lacrimal passages, infection etc.
90% of infants with lacrimation are automatically cured, during the first year of life.
In cases where obstruction persists, topical massages, topical antibiotic drops (only when there is severe discharge and only for a few days), catheterization of the nasolacrimal duct (with or without insertion of silicone tubes), are recommended.

The success rates of catheterization are over 90%, while, in some cases, repetition is required. The success rate significantly drops, depending on the age of the child, the older the child, the higher the relapse rates.
In rare cases, surgery of greater extent is required (Dacryocystorhinostomy).