Life Science Encyclopedia

Epiphora is excessive tear production, usually a result from an irritation of the eye. A clinical sign or condition that constitutes insufficient tear film drainage from the eyes in that tears will drain down the face rather than through the nasolacrimal system.^[1]

Aetiology

Causes of epiphora include occular irritation and inflammation (including trichiasis and entropion) or an obstructed tear outflow tract which is divided according to its anatomical location (ie. ectropion, punctal, canalicular or nasolacrimal duct obstruction). The latter is often due to aging (a spontaneous process), infection (ie. dacryocystitis), rhinitis, and in neonates or infants, failure of the nasolacrimal duct to open.

Other less common causes of epiphora is paradoxical lacrimation which is due to an abnormal regeneration of facial nerve (CN VII) as a sequelae of Bell's palsy. The nerves that formerly went to the salivary glands regrow to the lacrimal gland causing excessive tearing. Often, these individuals experience excessive tearing whilst eating as movement of the muscles of mastication is controlled by the facial nerve and hence their activation also causes tearing. The previous statement is incorrect because the facial nerve does not innervate the muscles of mastication. The muscles of mastication are innervated by the mandibular division of the trigeminal nerve.

Diagnosis

Diagnosis of epiphora is clinical by history presentation and observation of the lids. Fluorescein dye can be used to examine for punctal reflux by pressing on the canaliculi in which the clinician should note resistance of reflux as it irrigates through the punctum into the nose.

Management

If epiphora is caused by ectropion or entropion, lid repair is indicated. Punctal irrigation is also required. In infants with nasolacrimal defects, a nasolacrimal duct probe is used and a tube replacement, either temporary (Crawford) or permanent (Jones), is carried out. A surgical procedure called a dacryocystorhinostomy is done to join the lacrimal sac to the nasal mucosa in order to restore lacrimal drainage.

References

1. ^ http://www.revoptom.com/handbook/sect1i.htm