The lacrimal gland is located, in a shallow depression, in the upper outer orbit. The larger orbital portion of the lacrimal gland sits above the levator muscle and is continuous, around the lateral edge of the muscle, with the smaller palpebral part of the gland. Several ducts pass from the orbital portion to the palpebral part to open into the superior conjunctival fornix. The lacrimal artery, a branch of the ophthalmic artery, supplies the gland and tear secretion is controlled by sympathetic and parasympathetic neurons.
The primary functions of the tear film include:
- Providing a smooth moist corneal surface
- Antimicrobial defence against infection
- Aiding removal of debry from the ocular surface
Failure to produce adequate tears results in keratoconjunctivitis sicca or dry eye eg Sjogren’s syndrome. Symptoms vary but can include sore, stingy or gritty red eyes, photophobia and intermittent blurred vision.