Fifteen gallons of tears. That’s the low estimate for how much fluid the average person’s eyes produce in one year; some of us run as high as 30 gallons. We don’t think much about those tears until they stream down our cheeks in joy or sorrow. But healthy people tear up through the day in a steady, lubricating flow that rolls over our eyes. If that flow ever dries up, dry eye disease develops, and problems follow.
The Role of Tears
Tears do more than wash away dust and debris. They protect the front of the eye from dryness, injury and microbial infections. The tear film covering the conjunctiva and cornea contributes to the refractive power of the eye, helping it to focus light.
Tears consist of a complex fluid, an inner mucous layer produced by conjunctival cells and an outer lipid layer produced by Meibomian glands along the eyelid margin. The mucous layer helps tears adhere to the eye, and the lipid layer reduces evaporation.
Dry Eye Disease
Though patients and doctors sometimes speak of “dry eye disease” when this lacrimal system breaks down, the more appropriate term is ocular surface disease. OSD can contribute to discomfort, blurred vision, eyestrain, even scarring of the cornea and permanent vision loss in severe cases.
It’s caused by malfunctioning lacrimal glands (too few tears) or Meibomian glands (poor tear quality). Dehydration, lack of healthy fats in the diet, hormonal changes in the body, medication use or autoimmune and systemic problems (such as rheumatoid arthritis or thyroid dysfunction) can cause this condition.
We’re more likely to get it as we age, and women are more prone to OSD than men. Genetics play a role. So does the amount of time we spend on digital devices or tasks performed close to the eyes, overuse of contact lenses, and poor closure of lids or use of a C-PAP breathing machine while sleeping. Inside environments contribute, too: Heat dries out the air in our homes, while ceiling fans or automobile air conditioning blowing in our faces may bother us.
Ideally, we fix the problem by making more and healthier tears. Proper hydration and a diet rich in omega 3s can help. Daily hot compresses increase the oil component in tears. If those changes aren’t enough, artificial tears or doctor-prescribed eye drops with the right PH balance may work without disrupting the natural tear film. Plain water isn’t a good substitute: It has a different molecular construction and pH balance than tears, and it can carry microorganisms that promote inflammation and irritation.
If none of those treatments solves the problem, your eye doctor will propose procedures to keep tears on the surface of the eye longer and/or reboot the oil glands in the lids. Punctal plugs installed where tears drain off the eyes into the nasal passages will slow down their progress. Treatments such as Lipiflow and iLux apply heat to the Meibomian glands, melting the trapped oils within and allowing them to descend.
Naturally, OSD varies from person to person and requires specific attention. So, the first step is to consult your eye doctor to figure out what will work for you. The disease has no cure, but the wide array of options for managing symptoms gives almost every patient a better quality of life.