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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.
The lacrimal punctum (pl.: puncta) or lacrimal point is a minute opening on the summits of the lacrimal papillae, seen on the margins of the eyelids at the lateral extremity of the lacrimal lake. There are two lacrimal puncta in the medial (inside) portion of each eyelid. Normally, the puncta dip into the lacrimal lake.
The lacrimal caruncle is found at the medial canthus of the eye. [1] It consists of skin, hair follicles, sebaceous glands, sweat glands, accessory lacrimal tissue and other tissues that are present in the skin and accessory lacrimal glands. [1] [2] Its non-keratinized epithelium resembles the conjunctival epithelium. [2]
There are approximately forty Krause glands in the region of the upper eyelid, and around 6 to 8 in the region of the lower lid. [2] The function of these glands are to produce tears which are secreted onto the surface of the conjunctiva. There are rare instances of tumors associated with Krause's glands.
Dacryocystitis is an infection of the lacrimal sac, secondary to obstruction of the nasolacrimal duct at the junction of the lacrimal sac. [1] The term derives from Greek dákryon 'tear' cysta 'sac' and -itis 'inflammation'. [2] It causes pain, redness, and swelling over the inner aspect of the lower eyelid and epiphora.
Along the inner margin of the tarsus are modified sebaceous glands known as tarsal glands (or meibomian glands), aligned vertically within the tarsi: 30 to 40 glands in the upper lid, and 20 to 30 in the lower lid, which secrete a lipid-rich product which helps keep the lacrimal secretions or tears from evaporating too quickly, thus keeping the ...
Involutional stenosis is probably the most common cause of nasolacrimal duct obstruction in older people. It affects women twice as frequently as men. Although the inciting event in this process is unknown, clinicopathologic study suggests that compression of the lumen of the nasolacrimal duct is caused by inflammatory infiltrates and edema.
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.