What is Dry Eye?

Home What is Dry Eye?

Dry eye disease is most commonly caused by a deficiency in one or more areas of the tear film. The tear film, or tears, are made up of three separate layers: Mucin, Aqueous and Lipid

The Three Layers of Tear Film

  • Mucin. This layer is the inner layer and is responsible for protecting the most sensitive part of your eye, the cornea. It allows the other layers of the tears to spread evenly across the surface of your eyes.
  • Aqueous. This is the middle, watery layer and is the main component of your tears. It is produced by the lacrimal glands above your eyelids. A deficiency in this layer of your tears can be caused by a variety of issues, from gland dysfunction to dehydration.
  • Lipid. This is the outer, final layer of the tear film. This layer is made of oily lipids, created by the Meibomian Glands, and are designed to keep your tears from evaporating too quickly. A deficiency in this layer is caused by Meibomian Gland Dysfunction and is one of the leading causes of dry eye disease.

The name “dry eye” can be a little confusing since one of the most common symptoms involve excessive watering!

It makes more sense, though, when you learn that the eye makes two different types of tears.

The first type, called lubricating tears, is produced slowly and steadily throughout the day. Lubricating tears contain a precise balance of mucous, water, oil, nutrient proteins, and antibodies that nourish and protect the front surface of the eye.

The second type of tear, called a reflex tear, does not have much lubricating value. Reflex tears serve as a kind of emergency response to flood the eye when it is suddenly irritated or injured. Reflex tears might occur when you get something in your eye, when you’re cutting onions, when you’re around smoke, or when you accidentally scratch your eye.

The reflex tears gush out in such large quantities that the tear drainage system can’t handle them all and they spill out onto your cheek. Still another cause of reflex tearing is irritation of the eye from lack of lubricating tears. If your eye is not producing enough lubricating tears, you have dry eye.

Signs of Dry Eyes:

  • Red Eyes
  • Burning
  • Itching
  • Foreign Body Sensation
  • Sandy/Gritty Feeling
  • Light Sensitivity
  • Watery Eyes
  • Pain/Soreness in or Around the Eyes
  • Red/Irritated Eyelids
  • Tired Eyes
  • Contact Lens Discomfort
  • Dry Mouth

Common Causes of Dry Eyes:

  • Aging. Even though anyone can have dry eye, this condition becomes more common the older you get.
  • Medications such as high blood pressure meds, anti-histamine, cholesterol meds, anti-depressants, anti-inflammation meds
  • Computer use with reduced blinking
  • Laser eye surgery ( LASIK & PRK)
  • Menopause
  • Vitamin A deficiency
  • Environmental – wind, weather, elements
  • Sjögren’s syndrome
  • Auto Immune Diseases
  • Blepharitis
  • Dehydration
  • Allergies
  • Low Humidity like living in Alaska!
  • Smoking
  • Contact Lenses Wear
  • Rheumatoid arthritis or thyroid disease
  • Frequent Flying on airplanes
  • Glaucoma eyedrops
  • Makeup and Eye makeups
  • Eyelash extensions

For the majority of Dry Eye sufferers, the actual underlying cause is Meibomian Gland Dysfunction.