Genetic clues to the cause of short-sightedness have been uncovered that could lead to new treatments.
Scientists discovered 24 new genes that help trigger the currently incurable condition.
They include genes involved in brain and eye tissue signalling, eye structure, and eye development.
Carriers of the highest risk genes have a 10-fold increased likelihood of developing short-sightedness, or myopia.
An estimated 30% of Western populations and up to 80% of Asian people suffer from some degree of short-sightedness.
Find our what your eyes can reveal about your wellbeing..
Different Shaped Pupils
The pupils (the black circle in the centre of the eye) in normal people are usually symmetrical, the same size and react in the same way when exposed to sunlight. If one pupil is bigger or smaller than the other, there could be an underlying medical problem. Experts claim that differences in pupil size could indicate that the person is at a higher risk of having a stroke, brain or optic nerve tumour, or brain aneurysm. <strong>If you spot any changes to your pupils, raise this with your GP, optometrist or ophthalmologist.</strong>
Dry Eyes (Sensitive To The Light)
If your eyes are always dry and ultra sensitive to light, it could signal an immune system disorder, <a href="http://www.nhs.uk/conditions/Sjogrens-syndrome/Pages/Introduction.aspx" target="_hplink">Sjogren</a>, which impairs the glands in the eyes and mouth. The condition affects women over 40 with autoimmune disorders, such as rheumatoid arthritis or lupus. <strong>Seek advice from your GP if this sounds like you, as artificial lubricant can be prescribed and you'll be advised to drink plenty of water.</strong> "Dry eyes are more common in women over 50 due to hormonal changes," adds Larry Benjamin from <a href="http://www.rcophth.ac.uk/" target="_hplink">The Royal College of Ophthalmologists. </a>
If your eye is covered in a 'cloud' and your vision is impaired because of it, you may have a cataract. This causes a clouding of the lens inside the eye and can be corrected with surgery. This condition mainly occurs in older people but in younger people, it is commonly caused as a side effect of diabetes, tumours and some medication.
Although there are many things that can cause itchiness around the eyes, the most common reason could be pinpointed to an allergic reaction. The eye, and the area around it, is delicate and sensitive and more vulnerable to infections and allergies. Triggers could be anything from airborne pollens, dust or animal fur. <strong>If you suffer from red itchy eyes, try antihistamines to ease the redness, or visit your GP to organise an allergy test. </strong> If your eye and eyelids become puffy and sore, this could be a sign that you're sleep deprived. "Fluid moves around your head when you sleep and normally disperses when you wake from a good night's sleep. "However, lack of sleep causes this fluid to retain around the eye area for longer," explains Larry Benjamin from <a href="http://www.rcophth.ac.uk/" target="_hplink">The Royal College of Ophthalmologists</a>.
If your eye has a light grey ring around the cornea (the coloured circle in your eye), you may have a condition called <a href="http://www.mayoclinic.com/health/arcus-senilis/AN01493" target="_hplink">arcus senilis</a>, which is often linked to high cholesterol levels and triglycerides - fatty acids found in the blood. These are linked to higher risk of heart disease and strokes, so if you spot a grey ring circling your eye, <strong>visit your GP to discuss changing your diet. </strong>
Although it's natural for eyebrows to become thinner as we age, if you notice your brows literally 'disappearing' from the outer third of the eyebrow, this could signal a thyroid dysfunction. Loss of eyebrow hair from the outer edges of your face is a common sign of hyperthyroidism (overactive thyroid) or hypothyroidism (under active thyroid). Thyroids help regulate the metabolism and thyroid hormones are vital for hair production. <strong>If in doubt, book an appointment with your GP.</strong>
"Watery eyes can indicate infection," explains Larry Benjamin from <a href="http://www.rcophth.ac.uk/" target="_hplink">The Royal College of Ophthalmologists</a>. "If the eye is watery, you've most likely got an infection caused by a virus. If it's sticky, you might have a bacterial infection." If your vision becomes blurry, this could also be the result of <a href="http://www.allaboutvision.com/cvs/" target="_hplink">Computer Vision Syndrome</a> (CVS), caused by eyestrain from lack of contrast on a computer screen. This makes the eyes work harder focusing on the pixels on the screen. <strong>If in doubt, speak to your employer about booking an eye test, which is free if you use visual display units (VDU) for long periods of time. </strong>
Yellow lumps, also known, as xanthelasma palpebral, which appear on your eyelids could be a warning signal that your cholesterol levels are sky high. These are fatty deposits, which clump together and live in the eyelid. These are very often mistaken for a stye. Although these are quite common, <strong>it's best to get them checked by your optician or GP, as it can sometimes be an early sign of coronary artery disease. </strong> If you spot any coloured spots on your eyelids, in particular brown spots, <strong>visit your GP immediately</strong> as it could be an early sign of skin cancer. These usually appear on the lower part of the eyelid and will look a brownish colour with tiny blood vessels.
If your eyes are always blood-shot with broken blood vessels making them look blotchy and sore, this could be a sign that you have high blood pressure. Your optician will be able to confirm this by looking at your retina (the inner part of the eye). High blood pressure causes the blood vessel in the retina to 'kink and twist', causing them to break and look red. This could increase your risk of a stroke, so <strong>raise it with your GP as soon as possible. </strong>
If the whites of your eyes have a yellow tint rather than pearly white, you may have jaundice, which is linked to various liver and gall bladder problems. A simple blood test will confirm this, so if you're in doubt, <strong>book an appointment with your GP. </strong>
The problem occurs when the eye grows too long and light is focused in the wrong place, in front of the retina's photoreceptors. This results in a blurred image.
The error can be corrected with glasses or contact lenses, but high levels of myopia are associated with an increased chance of retinal detachment, glaucoma and macular degeneration.
Although myopia is highly heritable, information about the genes responsible has been lacking.
To investigate the genetic causes of short-sightedness, scientists analysed data on more than 45,000 individuals.
They found 24 new genes for the trait, and confirmed the identity of two discovered previously.
Lead scientist Professor Chris Hammond, from the Department of Twin Research and Genetic Epidemiology at King's College London, said: "We already knew that myopia - or short-sightedness - tends to run in families, but until now we knew little about the genetic causes.
"This study reveals for the first time a group of new genes that are associated with myopia and that carriers of some of these genes have a 10-fold increased risk of developing the condition.
"Currently myopia is corrected with glasses or contact lenses, but now we understand more about the genetic triggers for the condition we can begin to explore other ways to correct it or prevent progression. It is an extremely exciting step forward which could potentially lead to better treatments or prevention in the future for millions around the world."
The research is reported today in the journal Nature Genetics.
Don’t forget your eyes
Treat your eye health as you would any other part of your body. Most people are recommended to go for a check-up every two years, unless otherwise advised by an optometrist. Even if you think your vision is fine, some eye conditions, for example open angle glaucoma, may not show symptoms.
Be risk aware
People of Asian or African Caribbean descent or people over 40 should go for a sight test at least every two years as they are more at risk of developing eye disease
If you smoke, you have another good reason to kick the habit. Smoking is linked to blindness. Current smokers are four times more likely to develop macular degeneration – a progressive disease that can lead to significant sight loss – compared to past smokers or non-smokers.
It’s all relative
Talk to your relatives about your family eye health history as some eye conditions, such as glaucoma, can run in families. It’s important to think about your child’s eyes and to be aware of their vision, especially if there is a family history of lazy eye or squint or family members wore particularly strong spectacles when they were young.
Be cool in the sun
Protect your eyes when it is sunny or when you’re in high glare areas such as near snow or water. Cumulative UV exposure may damage your eyes. When choosing sunglasses make sure that they are safe as well as stylish! Look out for the CE or BS EN 1836:2005 marks – this ensures that they provide a safe level of protection from the sun’s damaging UVA and UVB rays. Don’t forget to also protect children’s eyes – they’re more at risk.
Protect your eyes
If you work with hazardous or airborne materials at work or home wear safety glasses or protective goggles to protect your eyes from injury.
Keep fit and healthy
Regular exercise is essential to stay fit and healthy but it is also important that when playing sports such as squash that you wear protective eye wear such as helmets or sports goggles to protect your eyes from a flying ball.
Protecting your eyes starts with the food you eat. Nutrients rich in omega-3 fatty acids, zinc and vitamins C and E may help to prevent age-related vision problems such as macular degeneration and cataracts. Recommended foods include green leafy vegetables and oily fish, such as salmon, and citrus fruits.
Contact lens care
If you wear contact lenses make sure you look after them properly. Thoroughly wash and dry your hands before touching your contact lenses or your eyes, and only ever clean your contact lenses using the solution recommended by your optometrist. Never shower, sleep or swim with your contact lenses in because this can put you at risk of developing a serious eye infection which could lead to blindness. Also, don't wear them for longer periods than recommended by your optometrist.
Environmental factors such as reading, lack of outdoor exposure, and a higher level of education are also known to raise the risk of myopia.
The condition is more common among people living in urban areas. How these external influences might be affected by people's genetic make-up will be investigated next by Prof Hammond's team.
Currently one drug, atropine, is available that may reduce the progression of myopia. However, it dilates the pupils and causes problems with light sensitivity and reading. New options are badly needed, say the scientists.