Visual diagnosis: 2-month-old girl with left eye swelling, profuse tearing.

Nasolacrimal duct (NLD) obstruction is the most common cause of persistent tearing in a child younger than 1 year. Other possible causes include congenital eyelid abnormalities, chemical irritation, trauma, occult foreign body, congenital or early-onset glaucoma, and conjunctivitis. • In addition to NLD obstruction signs, dacryocystoceles also present with swelling over the nasolacrimal sac. The swelling often has a bluish discoloration. • Management of NLD obstruction requires a conservative approach with observation and nasolacrimal massage because spontaneous resolution occurs in approximately 90% by age 6 months and in more than 99% by age 12 months. Referral to an ophthalmologist for children with persistent symptoms should be deferred until at least ages 6 to 9 months. • Because of the high risk of complications with dacryocystoceles, especially infection, these patients require urgent ophthalmology referral. • Acute dacryocystitis presents with erythema, swelling, warmth, and tenderness of the lacrimal sac. The infection must be identified and treated early to prevent complications, such as periorbital and orbital cellulitis, meningitis, brain abscess, and sepsis.