Dry Eye

The tear film over the surface of the eye is a complex mixture of water, lipid (fatty substances), mucus and proteins. The term “dry eye” is a bit misleading because it suggests there is insufficient water. While that may be the case in some people, in others it is a deterioration in the quality of the tears rather than insufficient fluid.

The 3 main constituents of the tear film are:

  1. Aqueous – the watery layer produced by the lacrimal (tear) gland. Aqueous deficiency may occur in isolation or may be associated with dry mouth (sicca syndrome) and inflammation of the joints (Sjogren’s syndrome).
  2. Oil – produced by the meibomian or tarsal glands in the eyelids. Disruption of the oily layer may be associated with inflammation of the eyelid margin (blepharitis).
  3. Mucus – produced by goblet cells in the conjunctiva (the membrane over the white of the eye). A mucin deficiency may be age-related or may be associated with inflammation of the conjunctiva.

The usual complaint is of gritty, scratchy red eyes. People often say they feel they have grains of sand in their eyes. There may be a crust on the eyelashes in the mornings.

Dry eye syndrome has many causes, including being part of the normal aging process. Occasionally it is associated with disease processes elsewhere in the body. Contact lenses may aggravate a dry eye.

Symptoms include:

Burning and itching of eye/s
Persistent dryness
General eye discomfort
Scratchy, gritty feeling in eye/s
Feeling of a foreign body
Blurred vision
Sensitivity to bright light and glare