LACRIMAL DISORDER

NORMAL TEAR FILM: The tear film consists of three layers: a mucin layer, an aqueous layer, and an oil layer. The innermost (mucin) layer, secreted by the conjunctival goblet cells, promotes adherence of the aqueous component to the hydrophobic epithelia] surface of the conjunctiva and cornea. The aqueous layer, accounting for 90% of the tear film thickness, is secreted by the main lacrimal giand and the accessory lacrimal glands. The superficial (oily) layer, produced by the meibomian glands, prevents evaporation and abnormal breakup of the tears. A deficiency of any of these three layers can produce a dry eye syndrome. The most common cause of dry eye is aqueous tear deficiency. 

CANALICULITIS: Tearing, a prominent punctum, and swelling and tenderness over the canaliculus suggest the diagnosis of canaliculitis. Anaerobic bacteria (such as Actinomyces israelii) are often the cause. In patients with canaliculitis, material can usually be expressed from the punctum by "rnilking" the canaliculus. Effective treatment entails evacuation of the lacrimal system by irrigation and the use of topical penicillin. However, because canaliculitis is often associated with an anatomic abnormality, irrigation is not always effective. Occasionally, incision and curettage is necessary, and in rare instances it must be followed by canalicular repair over a silicone stent.

DACRYOCYSTITIS: Acute dacryocystitis presents as a tender swelling over the lacrimal sac, accompanied by pain, erythema, and discharge. Various organisms can cause dacryocystitis; Streptococcus pneumoniae and Staphylococcus aureus are the most frequent offenders. Bacterial infection can follow obstruction of the lacrimal system at either end of the bony nasolacrimal canal. Predisposing causes are nasal trauma, scarring from ocular surface disease, or a developmental anomaly. Systemic antibiotics are indicated in the acute phase of the inflammation. Chronic dacryocystitis producing permanent scarring or fistula formation requires dacryocystorhinostomy. Perhaps as many as one third of newboms can have a functional impatency of the distal end of the nasolacrimal duct, but this tends to disappear spontaneously during the first few months of life. If this impatency does not disappear, an acute or chronic dacryocystitis can ensue. Massage of the lacrimal system, combined with systemic or topical antibiotics, can be curative. If epiphora or dacryocystitis persists, gentle probing and irrigation of the Lacrimal system may be necessary to restore patency.