The middle (or aqueous) layer is the largest and the thickest. This layer is essentially a very dilute saltwater solution. The lacrimal glands under the upper lids and the accessory tear glands produce this watery layer. This layer’s function is to keep the eye moist and comfortable, as well as to help flush out any dust, debris, or foreign objects that may get into the eye. Defects of the aqueous layer are the most common cause of dry eye syndrome, also referred to as keratoconjunctivitis sicca (KCS).
Dry eye syndrome (DES) is a common disorder of the tear film, affecting a significant percentage of the population, especially those older than 40 years of age. DES can affect any race and is more common in women than in men.
Causes
Dry eye syndrome has many causes. One of the most common reasons for dryness is simply the normal aging process. As we grow older, our bodies produce less oil. The oil deficiency also affects the tear film. Without as much oil to seal the watery layer, the tear film evaporates much faster, leaving dry areas on the cornea.
Many people also find their eyes become irritated when reading or working on a computer. Contact lens wearers may also suffer from dryness because the contacts absorb the tear film, causing proteins to form on the surface of the lens.
Symptoms
- Itching
- Burning
- Irritation
- Redness
- Blurred vision that improves with blinking
- Excessive tearing
Increased discomfort after periods of reading, watching TV, or working on a computer
Treatment
Many find relief simply from using artificial tears on a regular basis. Closing the opening of the tear drain in the eyelid with special inserts called punctal plugs is another option. Simple lifestyle changes that can significantly improve irritation from dry eyes include drinking eight to ten glasses of water each day. This keeps the body hydrated and flushes impurities.
