The term “dry eye” refers to a wide spectrum of ocular conditions. The most common symptoms are dry, red, gritty, and even watery eyes. It often feels as though there is something foreign on your eye. Every time we blink, tear glands within the eyelid secrete tears. These tears lubricate the eye and help prevent infection. A healthy tear film consists primarily of a delicate balance of three layers. A thin outer oily layer reduces evaporation of the tears. Below the outer oily layer is a watery layer called the aqueous layer, which makes up 98% of the tear film. It helps rinse and clean the front surface of the eye. Below the aqueous layer is a thin layer of mucous that makes the cornea more wet-able. Normal tears nourish and refresh the eyes.
When the normal tear film breaks down, the eye begins to dry out. When that happens our eyes begin to burn and often the tear gland releases watery tears. These tears normally are only released to rinse out a foreign body or during emotional crying. They cause inflammation and irritate the eyes. That’s why dry eyes leads to red, burning, irritated eyes just like crying does.
Dietary intake of omega fatty acids helps with dry eye conditions. Because of the benefits to vascular, cardiac, cholesterol, skin and dry eyes, most clinicians suggest 2g to 3g per day of high-quality OTC fish oil capsules or flaxseed to patients with dry eyes..
There are three basic causes for dry eye, although in most cases there is considerable overlap in the cause for a particular person.
1. Anatomical - In this case the tear drainage system is too efficient and the normal tears are drained away too rapidly.
2. Aqueous Deficient - This is a reduction in the water volume of the tears. It may be due to an autoimmune syndrome called Sjogren's syndrome, hormonal deficiencies, or a side effect of certain medications.
3. Oil Deficient - There are about 80 Meibomian oil glands within the eyelids of each eye. When they become deficient the oily tear layer is not adequate and the normal tears rapidly evaporate away resulting in a dry eye. This is called Meibomianitis or Meibomian Eye Disease (MED). Recent research indicates that over 80% of dry eye cases relate to reduced Meibomian oil production.