Great question! Dry Eye Disease (DED) is a complex, yet common, condition with many contributing factors. To understand why eyes that tear excessively can be classified as dry, we must first discuss the underlying process in all cases of chronic Dry Eye – inflammation.
Only about 14% of all Dry Eye cases are due to a lack of tear production, whereas the vast majority of patients suffer due to improper tear composition. This is a subtle but important distinction. Although the exact composition of human tears is quite complex, on a high level it can be thought of as being made up of two* separate components; oil and water. The fact that (as we all know) these two don’t mix is actually beneficial for the surface of our eyes. The oil (coming from about 40 tiny glands in each upper eyelid and about 25 in each lower lid) creates a smooth “protective” outer layer of the tear film, keeping the mostly water containing portion of your tears spread across the cornea (the front surface of your eyes).
The cornea has an extremely high density of pain receptors, which is why even small exposures (an area without tears protecting it) can cause so much stinging, burning, and irritation. If the outer oil layer is missing in one area, the water layer evaporates quickly in between blinks and irritation occurs. One strategy your body uses in an attempt to protect your sensitive eyes is to produce more of the water component of your tears. This is how your eyes can be perceived to be too watery, when really, they’re responding to dryness. You may have Dry Eye if you consistently experience:
- Stinging, gritty, sandy, or a burning sensation in the eyes
- The constant feeling that you have something foreign in the eyes
- Sensitivity to light
- Excessive tearing or watery eyes
- Eye redness
- Blurred or “filmy” vision (especially if it seems to come and go)
- Difficulty wearing contact lenses comfortably
Whether you have a lack of overall tear quantity, poor oil quantity and/or quality, or some combination of both (the majority of cases), eventually the front surface of your eyes will become irritated. The end result of a repeated irritation is the same and can be summarized in one word – inflammation. We often think of inflammation in a negative light, however, it’s actually the most appropriate and well-intentioned response from your body to repair itself! The problem arises when the repair is never fully complete and the cycle of irritation and damage continues. When a condition transitions from acute to chronic, the continuous cycle of inflammation can actually be more of a nuisance when it comes to healing and improving your symptoms.
With significant improvements in our understanding of DED, modern approaches to managing the condition takes the role of inflammation into account significantly more than in the past, leading to many new and promising options to manage Dry Eye and to more effectively track improvements.
Stay tuned for part 2 of our Vision Wellness blog series on Dry Eye where we discuss the various ways we manage Dry Eye Disease, and why it’s important to get a personalized assessment and unique Vision Wellness plan for your eyes.
*The third component of the tear film is composed of mucus and, of the three layers, is the thinnest and closest to the cornea
ABOUT THE AUTHOR
Dr. Danny Walker hails from Mississauga, Ontario, and has been practicing Optometry in the Okanagan for the past three years. Dr. Walker completed both his Bachelor of Science and Doctor of Optometry degrees at the University of Waterloo, graduating in 2012. At Inspired Eyes Optometry, Dr. Walker enjoys being able to provide his patients with thorough examinations and personalized eye care. He has a special interest in protecting and maintaining optimal visual wellness through a variety of factors that include lifestyle and nutrition.
Dr. Walker is available for morning, daytime, evening and Saturday appointments at Inspired Eyes Creative Eyewear & Optometry. Call (250) 862-5900 or Book Online.
Very interesting! I often experience several of those symptoms, especially the filmy vision and stinging sensation. I look forward to learning how it can be managed effectively.