Anatomy of the Lacrimal Glands and Tear Production

The tear film is produced predominantly by the lacrimal glands lying supero-lateral to the eye. The basic secretion is water and salts in concentrations similar to plasma, with some additional proteins including lysozyme. This aqueous layer is then covered by a lipid secretion from the meibomian glands lying in the eyelids just posterior to the hair follicles. This secretion limits evaporation of the tear film and helps to prevent the film leaking from the corners of the eyes.

The tear film drains from the ‘punctum lacrimale’ found at the medial third of the upper and lower eyelids, travelling via canaliculi to the lacrimal sac adjacent to the eye. The sac drains via the nasolacrimal duct to open in the inferior meatus of the nose.