Dry Eyes and Tear Film Deficiency

  • Tears have several important functions:

    • They wash away debris and waste products from the eye surface
    • They keep the cornea moist and comfortable. If the cornea starts to dry out, vision will blur
    • Provide nutrients to the eye and carry immune substances to help prevent and fight infections

    The tears consist of three layers, each produced by a different set of glands located on the conjunctiva and the eyelids. The layers need to mix in just the right balance, otherwise the tears will either not lubricate the eyes correctly or evaporate from the eye surface too quickly. The symptoms of dry eyes include:

    • Blurred vision, especially after concentrated work like reading and driving
    • Burning or irritated eyes
    • Sandy, gritty, scratchy
    • Sore or stinging
    • Persistently watery eyes
    • Redness
    • Sensation of dryness
    • Decreased comfort with contact lens wear

    WHY DO MY EYES WATER IF THEY’RE DRY?

    If the tears are not lubricating the eyes effectively, then the eyes will not be moist and comfortable. This will cause irritation and stimulate more tear production. These reflex tears are more watery due to the gland that secretes them, so they are much more unstable and tend to run off the eye surface very easily.

    WHAT CAUSES IT?

    • Aging: The level of tear production decreases with age. At 65, we produce about 40% of the tears as at 18
    • Environment: Dry, windy weather, heaters and air conditioning all cause greater evaporation of tears from the eye surface
    • Hormonal changes: Pregnancy and menopause both see hormonal changes that will alter tear production