Dry eyes: causes, symptoms and how to get relief

What dry eye is

Every blink spreads a thin film of tears across the front of your eye. That film has three parts: a watery layer, a mucus layer that helps it stick, and an oily layer on top that stops it evaporating. The oil comes from tiny glands along the edges of your eyelids.

Dry eye happens when there are too few tears, or when the oily layer is poor and the tears evaporate too fast. The second cause is the more common one. Either way, dry patches form on the surface of the eye and it becomes irritated.

Symptoms

• a gritty or sandy feeling, as if something is in your eye
• burning or stinging
• redness
• tired or heavy eyes, especially in the afternoon and evening
• vision that blurs and then clears when you blink
• sensitivity to light and wind
• difficulty wearing contact lenses
• stringy mucus in the corners of the eyes
• watery eyes

That last one confuses people. When the surface of the eye dries out, it sends a distress signal and the tear gland floods the eye with watery tears. Those emergency tears lack the oily layer, so they run down your cheek without fixing the dryness.

Common causes

• Screens. We blink roughly a third as often when we concentrate on a screen. See digital eye strain and the 20-20-20 rule.
• Dry air. Air conditioning, heaters, fans, aircraft cabins and the dry Highveld winter all speed up evaporation.
• Age. Tear production declines from middle age.
• Hormonal changes. Dry eye is more common in women, particularly after menopause.
• Blocked oil glands and eyelid inflammation (blepharitis). This is the most common underlying cause.
• Contact lenses.
• Medicines. Antihistamines, some antidepressants, some blood pressure medicines, acne treatment and others can reduce tears.
• Health conditions, including diabetes, thyroid problems, rheumatoid arthritis and Sjogren's syndrome.
• Smoke, wind and dust.

Relief you can start today

Lubricating eye drops

Artificial tears from a pharmacy are the mainstay. Use them regularly, not only when your eyes already hurt. If you need drops more than four times a day, choose a preservative-free type. Gels and ointments last longer but blur your vision for a while, so they are best at bedtime. Avoid drops sold to "take the red out". They do not treat dryness and can make redness worse over time.

Blink breaks

Follow the 20-20-20 rule at screens: every 20 minutes, look at something 6 metres away for 20 seconds, and blink fully a few times. Position your screen slightly below eye level, so that your eyes are less wide open.

Warm compresses

Hold a clean, warm (not hot) facecloth over your closed eyes for 5 to 10 minutes, then gently massage the eyelids towards the lashes. This softens the oil in the eyelid glands. Done daily, it is one of the most effective treatments for evaporative dry eye.

Clean eyelids

Wipe along the lash line with a clean, damp cloth or a lid-cleaning wipe, particularly if you have crusting or wear eye make-up.

Change the environment

• Aim car vents and fans away from your face.
• Use a humidifier, or place a bowl of water near a heater, in winter.
• Wear wraparound sunglasses outdoors on windy days.
• Drink enough water, and do not smoke.

Food

Oily fish such as pilchards and sardines provide omega-3 fats, which may help the oily layer of the tears. The research on supplements is mixed, but eating fish regularly is a reasonable step. See the best foods for eye health.

When to see an optometrist or doctor

Make an appointment if your symptoms have lasted more than two weeks despite using drops, if they affect your reading or driving, or if you depend on drops many times a day. Dry eye that keeps coming back usually has an underlying cause that can be treated, and it can be confused with allergies and with an out-of-date prescription.

See a doctor the same day if a dry or red eye becomes painful, very sensitive to light or blurry, or if you wear contact lenses and one eye turns red and sore.