Dry Eye

The tear film is more complicated than most people know. It contains 3 distinct layers that all need to be present in the proper proportions in order to maintain clear, stable vision.

• The cornea is the tissue that divides the outside and inside world of the eye

• The mucus layer acts like a slime coating to keep the cornea from drying out. This can over-produce when the eye is irritated to form a slick coating for the eye, and is often the stringy, white goo that comes out of your eyes when they are irritated from dry eye, allergies, or injury.

• The aqueous layer (water layer) contains water, salt, and immune cells that fight infections in our eyes. This is the layer we think of as tears. The salt and water proportions have to be correct, because extra “salty” tears make the eye more prone to inflammation.

• The lipid (oil) layer is produced by the meibomian glands in the top and bottom eyelids. These glands produce the oil that acts as the barrier between the water layer and the outside air, preventing wind from evaporating all the water off your eyes. The oil layer also provides the lubrication so your eyelid has no friction against your eyeball.

Meibomian Glands are an important part of evaluating your dry eye treatment. These glands are responsible for the oil layer of your tear film. Over time, chronic inflammation, demodex mites, and other ocular surface issues can lead to the clogging and destruction of these glands. Once lost, these glands are unlikely to recover, and so it is important to evaluate these glands as part of a comprehensive eye exam. Gland loss can sometimes have few or no symptoms, so make sure that your eye doctor evaluates the health of these glands. Often, symptoms do not start until a moderate to severe loss of gland tissue is already present.