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Tears are produced by the lacrimal gland, situated just outside the eye. Blinking the eyelids distributes the tears to keep the eyes moist, clean and lubricated. Excess tears are drained via the punctum through the tiny channels called canaliculi located on the inner side of the eyes into the tear sac, from there to the tear duct, the nose and finally down the throat.
A punctal plug, also known as tear duct plug or lacrimal plug, is a small medical device that is inserted into the tear duct (puncta) of an eye to block the duct. This prevents the drainage of liquid from the eye. They are used to treat dry eye. Artificial tears are usually still required after punctal plug insertion. [1]
Causes of epiphora are any that cause either overproduction of tears or decreased drainage of tears, resulting in tearing onto the cheek. [2] This can be due to ocular irritation and inflammation (including trichiasis and entropion) or an obstructed tear outflow tract, which is divided according to its anatomical location (i.e., ectropion, punctal, canalicular or nasolacrimal duct obstruction).
Around 6% of infants have congenital nasolacrimal duct obstruction, or dacryostenosis, usually experiencing a persistent watery eye even when not crying. If a secondary infection occurs (dacryocystitis), purulent (yellow / green) discharge may be present. Most cases resolve spontaneously, with antibiotics reserved only if conjunctivitis occurs.
Persons with dry eye conditions can be fitted with punctal plugs that seal the ducts to limit the amount of fluid drainage and retain moisture. During an ear infection, excess mucus may drain through the nasolacrimal duct in the opposite way tears drain. [citation needed] In humans, the tear ducts in males tend to be larger than the ones in ...
Figure 1.0 - Basic anatomical features of the human eye. Ophthalmic drug administration is the administration of a drug to the eyes, most typically as an eye drop formulation. Topical formulations are used to combat a multitude of diseased states of the eye. These states may include bacterial infections, eye injury, glaucoma, and dry eye. [1]
The CDC warned that EzriCare Artificial Tears eyedrops may be linked to a drug-resistant bacterial infection that has caused permanent vision loss and one death.
A punctal plug may be inserted into the tear duct by an optometrist or ophthalmologist, decreasing the removal of natural tears from the affected eye. [ 8 ] The use of contact lenses may help prevent the abrasion during blinking lifting off the surface layer and uses thin lenses that are gas permeable to minimise reduced oxygenation.