Lacrimal Drainage Obstruction Associated with Topical and Systemic Medications

A wide array of pathogenic factors has been associated with lacrimal drainage system obstruction including inflammatory conditions originating from the eye, conjunctiva, lacrimal mucosa, nose and paranasal sinuses; trauma; congenital abnormalities; radiotherapy and neoplasms. Inflammatory conditions initially cause lac-rimal mucosal swelling but may lead to fibrotic narrowing or obstruction of the nasolacrimal drainage conduit. Descending inflammation from the eye or ascending inflammation from the nasal cavity may cause swelling of the mu-cous membranes of the nasolacrimal duct, re-modeling of the helical arrangement of connective tissue fibers, or malfunction in the subepi-thelial cavernous body causing reactive hyper-emia and temporary occlusion of the nasolac-rimal duct system. The submucosa of the naso-lacrimal duct contains arterioles with sphinc-ters and cavernous vessel complexes; these can cause swelling and approximation of the lumen depending on the amount of blood flow. Due to constriction of tissue within a bony canal, any swelling inevitably leads to blockage. Structural epithelial and subepithelial changes may lead to fibrous closure of the lumen or to a non-functional segment causing chronic epiphora and discharge, however the system may seem patent to irrigation. There are reports on induced inflammatory and fibrotic changes in the conjunctival surface in association with medications especially topical anti-glaucoma and systemic anti-neoplastic agents. Such changes may be related to the medications themselves, the preservatives in the commercial preparations, or the duration of treatment. It seems likely that similar changes may occur in the epithelium and subepithelial tissues of the lacrimal drainage system, resulting in stenosis and occlusion. The upper lac-rimal system is close to the conjunctiva and fornix and is expected to be more affected by topical medications than the lower lacrimal system; this is now accepted as a fact in the literature. Topical agents including antiglau-coma medications such as timolol, pilocarpine and dorzolamide; antiviral drops such as ido-xuridine and trifluridine; and systemic medications such as fluorouracil and docetaxel are now considered as risk factors for upper lac-rimal system obstruction. A more recent question is whether such medications may have a similar effect on the lower lacrimal system, i.e. the nasolacrimal duct. Kashkouli et al conducted a prospective case series in which diagnostic probing of the canaliculi and irrigation of the nasolacrimal duct was performed in 98 glaucoma patients (130 eyes) taking topical antiglaucoma drops and 178 non-ocular patients (280 eyes) who were taking no topical medications. The two groups were matched for age, sex and associated systemic disorders. …