Information & Advice
Boots optometrist Dr Rob Hogan talks eyecare. Read more on dry eyes, tired eyes, twitching eyes and eye infections. Plus – how to chop onions.
In fact, we all produce tears every single day – and they form a protective barrier for our eyes.
"Tears are like the oil in an engine. They lubricate the eye," explains Boots optometrist Dr Rob Hogan. "Our tears carry nutrients. There's an anti-microbial agent in tears that stops our eyes becoming infected. They also contain oxygen."
Each time we blink, our eyelid wipes away the existing tears and replaces them with a fresh layer. Unfortunately, Rob says, the demands of modern life may take its toll on our blink rate.
"When we concentrate, we blink less than we normally would," he says. "85% of the sensory information we take in from the outside world comes through our eyes. They are the most important sensory organ which is why, when we're taking information in, we tend to blink less."
Modern technology such as computers or TVs all demand concentration. Even driving a car may affect our blink rate. "People are using their PCs and phones as diaries or for texting," says Rob. "All these things can affect our blink rate."
Why does this matter? "Well," Rob says, "the longer the gap between blinks, the more the tear film may evaporate. If we don't blink regularly, we're not allowing a fresh layer of lubricating tears to be built."
The older we get, the fewer tears we produce – particularly women, whose tear production is affected by hormonal changes. Certain medication may also affect our tear production – either by reducing it or occasionally increasing it.
Reduced tear production can result in a feeling of dryness and discomfort around the eyes. Studies have suggested that between 17-30% of people experience dry eye syndrome at some point during their life. If this is becoming a problem for you, Rob says to speak to your optometrist.
"Your optometrist will be able to check the constituents of your tears and check their volume to make sure they look normal," he says. You may be able to use eyedrops that can either help increase the volume of your tears or replace a specific part of the tear film.
You can also help yourself by being aware of external conditions and the effect they may have on your eyes. "Perhaps when you hit 'enter' on your computer, you can remind yourself to take a blink," says Rob. "Try to take time to look away from the screen across the room. And move fans and heaters away from your face."
However, there are medical conditions that can cause dry eyes. "If your eyelids are so dry they won't meet at night, you should speak to your GP or optometrist," says Rob.
After a long period of sustained concentration, such as reading, driving or watching TV, you may be aware that your eyes feel tired or dry. This may, Rob says, be a fluid problem, caused by a slower blink rate while you were concentrating.
It may also be a sign that you need some sleep. "We are supposed to have an average of eight hours' sleep and burning the candle at both ends is not good for your eyes," Rob says. "You can develop a condition called myotonia which is a slight twitch in the eye area. That's your eyes' way of letting you know they are tired. It's nature's way of saying, 'Slow down'. You need a bit of sleep, so heed the warnings."
However, tired eyes may also be the result of a focus problem. If you are not sleep-deprived, have tried eye drops and don't find the problem is improving after a week or two, consult your optometrist.
"Go along and have your eyes examined," says Rob. "Our eyes are quite often different in focus". That means the eyes and brain have to work harder than usual to work out which image they are processing. After a while, that can make the eyes feel tired. Your optometrist will be able to advise you how this can be corrected."
Poor tear production may affect your ability to wash out your eyes when faced with irritants in the atmospher
"Smoking is probably the most obvious irritant," says Rob. "It's a cloud of microscopic ash particles which can irritate the eye even if you have good tear protection."
Other eye irritations may be more related to the pH level of your eyes.
"The pH level in your eyes is around 7.6 so they are slightly alkaline," says Rob. "When your eyes come into contact with something acidic in the atmosphere, it can irritate them."The most everyday acidic irritants are onions. "When you cut into an onion, it activates a defence mechanism within the onion," says Rob. "The onion produces a chemical which acts as an acidic irritant and is released into the atmosphere as droplets. They irritate the surface of the eye."
If it's possible, carefully chop your onions under running water and that should help the problem.
Chillies are another common irritant. "Make sure you wash your hands thoroughly after handling them and try not to touch your eyes. If you wear contact lenses, take them out first," says Rob.
Wind and dry air – for example, from air conditioning – can also irritate the eye.
Irritated eyes can be soothed with eyedrops but, in severe cases, speak to your optometrist or pharmacist.
You may also find your eyes are irritated by bright sunlight – particularly if they are light-coloured.
"Your iris is a ring of muscle that controls light," says Rob. "If you have less pigment in your eyes (i.e. if your eyes are a light colour), more light gets into the retina and this may be irritating."
Sunglasses may help the problem but if you find you require more help, speak to your optometrist.
If you wear contact lenses and want them to continue feeling comfortable, aftercare is vital, according to Rob.
"Listen to the advice given to you by your optometrist. Get regular eye examinations and regular contact lens checks," he says. "Don't wear your contact lenses more than you are told to and don't use the same storage solution more than once. And replace the case regularly because the cases can harbour bacteria. Have an up-to-date pair of spectacles as a back-up."
If your eyes feel dry, be aware of external triggers – such as air conditioning or radiators – that may trigger the dryness.
"Some people find they can't wear contact lenses on a long haul flight," says Rob. "The oxygen levels are much lower on aeroplanes. Wear spectacles and, if you have a dry eye problem, make sure you carry a bottle of eyedrops in a clear plastic bag."
Another cause of dryness may be related to the kind of contact lenses you're wearing. "Older generations of soft hydrogel contact lens may actually dry your eyes," says Rob. "You may wish to consider trying a more modern lens which is made with silicone which is less dependent on the water level in
Bacterial conjunctivitis is an infection of the lining that covers the front of your eyes. It is caused by bacteria carried on your hands or something else that has come into contact with your eye. "Your eyelids may be stuck together when you wake up and the white part of one or both of your eyes will be red," says Rob. "Your eyes may feel 'gritty' or irritated."The first thing to do is treat the bacteria and you can speak to your optometrist or pharmacist about products that may help. However, if the infection is more severe, you should see your GP.
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