Dry eyes? Wear sunglasses even when it’s overcast and chilly!

Should you regularly find yourself wiping away tears, you might not think to blame dry eyes — but that’s the most likely cause, and the remedy may be as simple as wearing sunglasses, even on a cloudy, wintry day.

Dry eyes, while already a frequent problem affecting up to 30 per cent of those aged over 50, is becoming increasingly common. There has been a 19 per cent increase in the numbers diagnosed with dry eyes in the previous 12 months, according to a recent survey of 2,000 people by eyecare specialist firm Thea UK.

As well as a gritty feeling, dry eyes — counterintuitively — lead to the overproduction of tears, which is the body’s way of trying to rehydrate the eye’s surface.

And while for some it’s just a slight irritation, severe cases can lead to impaired vision and irreversible eye damage, says Alex Ionides, a consultant ophthalmologist at Moorfields Eye Hospital in London.

Dry eyes become increasingly common with age because ‘from the age of 50, the meibomian glands do not produce enough oily secretion to coat the cornea fully, which means the tears are not sealed in and are more likely to evaporate’, explains Mr Ionides

The eyes are usually lubricated by the tear film: the first layer is made up of what Mr Ionides likens to ‘transparent slime, which keeps the cornea [the clear outer surface of the eye] bathed in liquid’.

On top of this mucosal ‘slime’ is a watery layer of tears. This has antibacterial properties and helps keep the cornea in good health. On top of that is the upper oily layer produced by the meibomian glands (tiny glands in the eyelids), which seals the moisture in, preventing it from evaporating.

Dry eyes become increasingly common with age because ‘from the age of 50, the meibomian glands do not produce enough oily secretion to coat the cornea fully, which means the tears are not sealed in and are more likely to evaporate’, explains Mr Ionides.

People who have had laser eye surgery can also develop dry eyes, as the procedure can reduce the sensitivity of nerves in the surface of the eye, which would normally sense the need to produce tears

The condition is also common during the menopause, adds Nigel Kirkpatrick, a consultant ophthalmologist at Newmedica, a chain of NHS and private ophthalmology clinics.

‘The drop in oestrogen causes mucous membranes to dry out and glands produce less of the important hydrating fluids. This can leave the eyes feeling gritty and inflamed and looking red.’

But why are dry eyes becoming more common? This is, in part, due to the greater use of air conditioning and central heating (which also increase evaporation) and ever-longer periods spent staring at screens, since we blink less when doing so, and blinking spreads moisture around the surface of the eye.

But the increased use of contact lenses is also to blame, as this can cause more of your tear film to evaporate. ‘Contact lenses float semi-submerged in the tear film, which can disrupt the careful moisture balance, leading to increased evaporation,’ says Mr Ionides.

People who have had laser eye surgery can also develop dry eyes, as the procedure can reduce the sensitivity of nerves in the surface of the eye, which would normally sense the need to produce tears.

Dry eyes can affect vision, too. ‘The tear film is the first surface the light hits as it enters the eye,’ says Mr Ionides. ‘If it’s of poor quality, the image can be blurred, and if the cornea is not bathed with adequate tears, it can become uncomfortable and sensitive to light.’

‘Left untreated, severe dry eyes may lead to inflammation of the tissues around the eye, abrasion of the corneal surface and corneal ulcers,’ says Mr Kirkpatrick. ‘In extreme cases, it can lead to vision loss.’

 The eyes are usually lubricated by the tear film: the first layer is made up of what Mr Ionides likens to ‘transparent slime, which keeps the cornea [the clear outer surface of the eye] bathed in liquid’. On top of this mucosal ‘slime’ is a watery layer of tears. This has antibacterial properties and helps keep the cornea in good health. On top of that is the upper oily layer produced by the meibomian glands (tiny glands in the eyelids), which seals the moisture in, preventing it from evaporating

Mild cases can respond well to a warm flannel over the eyes. ‘The warmth melts the oily secretions in the meibomian glands, making them more runny, and gently massaging your eyes will help empty the contents of the glands onto the cornea to replenish the outer oily layer,’ says Mr Ionides.

And putting on a pair of sunglasses when you go out on a cold, windy day (regardless of whether the sun is shining) will limit the evaporation of your tears.

Sunglasses, like spectacles, create a pocket of warm, humidified air in front of the eyes, protecting them from the evaporating impact of a breeze.

And don’t forget to blink. ‘During periods of intense concentration, the eyes subconsciously avoid blinking to prevent losing sight of the intricate task in hand,’ says Mr Ionides. ‘But this allows more time for tears to evaporate.’

Taking a break from wearing contact lenses also helps if you have dry eyes, says Mr Ionides.

‘If you stop wearing them for a week or so, dry-eye symptoms often disappear as the tear film returns to its normal formulation and structure.’

As for eye drops, most contain the chemicals polyethylene glycol and propylene glycol, which coat the eye and prevent evaporation of the tear film.

Optometrists recommend picking ones which are ‘preservative free’ to avoid any chemicals which might irritate already irritated eyes.