Why are my eyes dry?

A dry eye is a term used to describe eyes that are not able to wet or lubricate themselves sufficiently. Ironically, dry eyes may also seem too moist, when tears run freely down your cheek. Let’s explain why this happens.

Your tears have three specific layers, a mucous layer, the water later and an oily layer. These three layers play a pivotal role in how your cornea is wetted with every blink, every day. The mucous layer is produced by goblet cells in the conjunctiva, tissue found covering the whites of your eyes and also the inner lining of your lids. The water or aqueous layer is produced in the tear or lacrimal gland, located above the temporal aspect of the upper lid. The oily layer is produced in glands found at the edge of the eyelids, called meibomian glands.

These three layers work together in the following way. The mucous layer is the layer closest to the cornea and functions as a glue layer. It helps the next layer, the watery tears, spread evenly over the corneal surface and keeps them from “rolling” off the eye. The oily layer is the “top coat” and helps prevent evaporation. So, if your tears are deficient in one of these layers, you have a type of dry eyes.

If you have been told your eyes are dry, but it seems you have excessive tears because they freely overflow your lids, you most likely have mucous lacking tears. This condition can happen to any person at anytime of their life, but most commonly occurs in people over 50 years of age.