Tears are made up of three separate secretions: a sticky base layer, a watery mid layer and an oily top layer (which slows tear evaporation). Dry eye is a sore, gritty sensation caused by too little tear production or poor quality tears that form an inadequate film.

Normally tears form a protective film over the surface of the eye, lubricating movement and washing away debris and any toxins. Dry eye can be painful and cause sensitivity to bright light or open air and wind.

Despite the name, the irritation of dry eye may trigger excessive tears. Dry eye may also redden the eyes, but it requires different treatment from allergic conjunctivitis and 'red eye'.


Symptoms

• Symptoms of dry eye may include any of the following:

• stinging or burning of the eye

• a sandy or gritty feeling as if something is in the eye

• episodes of excess tears following very dry eye periods

• a stringy discharge from the eye

• pain and redness of the eye

• episodes of blurred vision

• heavy eyelids

• inability to cry when emotionally stressed

• uncomfortable contact lenses

• decreased tolerance of reading, working on the computer, or any activity that requires sustained visual attention

• eye fatigue.

You should seek medical advice if:

• the eye is painful or red

• it is harder to see well or your vision is blurred

• the eye has a coloured discharge or your eyelids are stuck together on waking

• you have glaucoma

• you have rheumatoid arthritis or diabetes

• the dry eye persists for seven to 10 days, despite treatment.

Treatment

Blinking more often and using a warm compress to stimulate healthy operation of the eye’s lubricating glands are good self-help measures.

Lubricating eye drops containing artificial tears can help.