The lacrimal system.

The lacrimal system comprises of a series of anatomical structures with specific physiologic properties. Tearing from a nasolacrimal duct obstruction (NLDO) is the most common lacrimal system abnormality encountered by pediatric ophthalmologists. Most NLDOs spontaneously improve with conservative management by 12 months of age, but persistent or atypical cases may be treated with a procedure consisting of probing and irrigation of the lacrimal system. Other less common but significant lacrimal system abnormalities are also discussed.