Dry Eye Syndrome Lacrimal Functional Unit

Dry Eye Syndrome Lacrimal Functional Unit

The lacrimal functional unit (LFU) of the eye is made up of the cornea (the transparent front part of the eye; in addition to protecting the eye the cornea functions to refract, or bend, light acting as the eye’s outermost lens), the conjunctiva (a mucous membrane that covers the front of the eye and lines the inside of the eyelids for easy movement of the lids), the lacrimal gland (secretes the aqueous layer of the tear film), meibomian gland (responsible for the supply of meibum, an oily substance that prevents evaporation of the eye’s tear film),  the eye lids, and the sensory and motor nerves that connect them. The LFU maintains and protects the tear film which contains molecules responsible for the normal function of the ocular surface 1. Dry Eye Syndrome (DES) occurs when the LFU does not produce enough tears or when tears evaporate too quickly. The schematic below was adapted from: Singh,D. (2014)Dry Eye Disease: A review of diagnostic approaches and treatments. Retrieved from https://www.slideshare.net/dildarsingh58173/dry-eye-ppt-by-dr-dildar