Question: What are tears made of?
Tears play an important role in keeping us healthy. Tears keep the surface of our eyeballs clean and moist, and help protect our eyes from damage. Although they make appear to be nothing more than water, our tears are actually quite complex. Tears are made of mucus, water and oil. Mucus coats the surface of the eye and helps bind the tear layer to the eye. Without a healthy mucus layer, dry spots may form on the cornea
, the clear dome-like structure on the front of the eye. The water is really more of a saline (salt) solution that contains various vitamins and minerals vital to normal cell function. These nutrients are important for keeping the top layer of cells on the surface of the eye, the epithelium, healthy and functioning normally. The oil of the tear film prevents evaporation of the tears. Some people don't make enough oil (or sometimes too much oil), resulting in dry eyes
. If the oil component is not normal, the tears evaporate too quickly.
Our tears also contain natural antiobiotics called lysozymes. Lysozymes help to keep the surface of the eye healthy by fighting off bacteria and viruses. Because the cornea has no blood vessels, the tears also provide a means of bringing nutrients to its cells.
Bartlett, Jimmy D and Siret D Jaanus. Clinical Ocular Pharmacology, Second Edition, Pp 123-124. Copyright 1989, Butterworth-Heinemann.