Lacrimal stenosis

The pH of the normal tears has been determined by many investigators to have a mean value of 7.4, but there are wide variations. It is lowest on awakening as a result of acid by-products associated with relatively anaerobic conditions in prolonged lid closure and increases because of loss of carbon dioxide as the eyes open. The tears are more acid in contact-lens wearers due to the impediment of the efflux of carbon dioxide, and more alkaline in the case of diseases such as dry eye, severe ocular rosacea and lacrimal stenosis. 

If clear fluid is expelled from the nose without any fluorescein present, it is likely that rather than a true obstruction of the lacrimal drainage system a punctal stenosis or ectropion is the culprit.This diagnosis can be assumed by the feet that no fluorescein ever entered the drainage system during the Jones I test, in contrast to the situation where fluorescein enters the system but gets lodged deep within the drainage apparatus (scenario 3 above). 

Occlusion of the lacrimal puncta is called atresia when congenital and stenosis when it is acquired. Each produces true epiphora, although congenital cases tend to produce fewer clinical signs and symptoms than do acquired cases. 

Tear duct fibrosis develops in one of six patients with excessive lacrimation from fluorouracil (66). The eversion of the lower eyelid is reversible with conservative management (68) while the tear duct fibrosis may not be (69). Persistent lacrimation has been described in six patients receiving intravenous fluorouracil weekly for 6-10 months (69). Lacrimation persisted in five patients after the withdrawal of fluorouracil, suggesting an irreversible dacryostenosis. Lacrimal duct stenosis has also been reported (70). Bilateral cicatricial ectropion was also reported in a patient after topical administration of fluorouracil for the treatment of multiple facial actinic keratoses (71). If ectropion and tear duct stenosis progress, surgical correction may be required. 

Prasad S, Kamath GG, Phillips RP. Lacrimal canalicular stenosis associated with systemic 5-fluorouacil therapy. Acta Ophthalmol Scand 2000 78(l) 110-3. 

Sensory systems Excessive lacrimation is common with fluorouracil and affects 30% of patients [82 ]. Other ocular adverse reactions include blurred vision, ocular irritation and pain, photophobia, conjunctivitis, circu-morbital edema, ectropion, keratitis, and tear duct stenosis. Most patients can be managed symptomatically with methylcellulose or dexamethasone eye drops. Occasionally fluorouracil may need to be withdrawn and the symptoms usually resolve in 1-2 weeks [18 ]. Optic neuropathy is rare [79 ]. 

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