Dry Eye

The primary function of tears is to protect the eye, in particular the cornea which is the clear part of the eye over the iris and pupil.  We have a basal or base secretion of tears which keeps the eye moist.  We also have reflex tears when we cry or our eye is irritated.

In the tears there are three layers;

1.An oily outer layer which comes from the meibomian glands and helps to reduce evaporation.

2.The middle layer is the watery layer which keeps the eye moist.  This is mainly provided by many very small tear glands at the edges of the conjunctiva.

3.The layer closest to the cornea is a mucus layer which helps the tears to adhere to the surface of the cornea.  This layer is produced from cells on the surface of the conjunctiva.

If there are not enough tears or the quality of the tears is poor, then the surface of the eye can become dry.  We normally lose 25% of our tears to evaporation.  If the eyelids do not coat the tears over the surface of the eye well or the eye is increasingly open then more tears can be lost to evaporation.  If the eyes become dry they can be stinging or burning.  There may be scratchiness.  There may be excess mucus formation. 

Normal tear production deceases with age.  Dry eye is more common in post menopausal women, but can occur at any age in men or women.

Dry eyes can be associated with a particular pathology, such as arthritis or Sjogren’s syndrome. People who wear contact lenses may be more predisposed to dry eye. 

Treatment

Artificial tear drops can be used to treat dry eye.  These preparations are tear substitutes that are available in both bottle and individual use preservative free vials.  These drops may be quite thin or may be of a medium viscosity to prolong their duration of action.

If artificial tear drops are not sufficient then a gel or a lubricating ointment may be suggested. If the eye dryness is worst in the morning, then an ointment or gel at night time can be beneficial.

If there is severe dry eye then shielding glasses may reduce evaporation. Sometimes it is appropriate to block the outflow of tears from down the tear duct with punctal plugs. 

Occasionally drops that alter the immune qualities of the tears may be indicated.

Many systemic medications can aggravate dry eye and these should be discussed with your doctor.

If you have persistent pain or sudden change in your vision, report this to the doctor immediately via the Surgery, the Hospital or the Sydney Eye Hospital.

If you have concerns or questions, please call.