All that you should know about myopia
Actor Tom Cruise was rather cute in the movie Jerry Maguire, but he was out-cuted by another man – a little boy named Jonathan Lipnicki, who played Ray, a nerdy child in big spectacles.
The cuteness factor aside, specs should not be a regular part of a child’s life. Which is why it’s alarming to see so many children wearing glasses these days.
According to the Myopia Institute in the US, incidences of myopia or nearsightedness (seeing objects at a distance as blurry) affects 1.6 billion children worldwide, and in India, according to Dr Himanshu P Matalia, consultant (cornea, refractive surgery and ocular surface) at Narayana Health City, Bangalore, studies show that 7 to 10 per cent of children aged between five and 15 are myopic.
Why is this happening? You could blame TV and handheld devices, but here’s really why...
Nature vs nurture
If your child has been diagnosed with myopia, chances are that you are myopic too. “About 30 per cent of our patients have a family history of myopia,” says Dr Manish Sharma, senior consultant (paediatric ophthalmology) at Vasan Eye Care Hospital, New Delhi. The odds that a child needs glasses are three times higher if one parent wears glasses and increases to six times if both parents do.
But that isn’t true for all cases, adds Dr Shilpa Goel, consultant at Eye-Q Super-Speciality Eye Hospitals (paediatric, cataract and squint). “About six to 15 per cent of children with myopia come from families where neither parent is myopic,” she says.
So heredity apart, what’s the real cause of myopia? Studies seem to indicate that it stems from the fact that children these days tend to stay indoors more often.
Blame it on urbanisation, which leaves less room for the little ones to play outside, and blame parents who prefer having their kids at home studying rather than playing out. “This plays a part in triggering myopia at a very young age in our children,” explains Dr Matalia.
You can see how this works by looking up a study that compares six-year-old children of Chinese descent in Australia with the same age group of Chinese children in Singapore. Only 3.3 per cent of the children living in Sydney, Australia, had myopia, compared to 29.1 per cent of the children living in Singapore.
The difference, the researchers pointed out, was that Australian kids spent more than 13 hours per week outdoors, compared to a rather bleak 3 hours for the children in Singapore.
Another study done by researchers from Ohio State University found that a lack of sports and outdoor activities increased the odds of myopia in children who had two myopic parents, more than in those children with none or one myopic parent.
"The biological mechanics of myopia – what exactly is happening inside the eye, and how the environment may affect that biology – aren’t clear. But what we do know is that when we are indoors, we don’t need to see beyond a certain distance and slowly our eyes lose the ability to focus on faraway objects," explains Dr Sharma.
One school of thought also believes that a chemical called dopamine is responsible. Exposure to light increases the levels of dopamine in the eye and helps prevent the elongation of the eyeball which is the common cause of myopia.
Studies done by Kathryn Rose, a researcher of visual disorders at the University of Sydney’s, College of Health Sciences, have shown that spending at least 10 to 14 hours outside per week may prevent the early onset of myopia.
A review published in the journal of the American Academy of Ophthalmology in 2012 indicated that each hour spent outside per week reduces a child’s chances of developing myopia by two per cent.
When a child stays indoors, chances are that the toys he or she plays with include gadgets. Handheld devices like smartphones and tablets that need to be looked at closely could contribute to vision defects. The eyeballs are adaptive while they are developing, so when growing children look too closely, it significantly increases the risk of elongation of the eyeball.
“I believe that the sudden explosion in the numbers of myopic children is because today, we put a cellphone in their hands at the age of six, and then give them a tablet soon after,” says Dr Sharma. “So far, in all my years of work, I have met only one family that refused to have a TV.”
That said, TV has no direct permanent impact on the eyes. “TV sets don’t damage our eyes but they do reduce our scope of activity and shrink our world,” says Dr Matalia, “Ditto for smartphones.”
“Maintain a proper viewing distance because close-screen viewing causes vision deterioration,” says Dr Goel. Or just let the kids go out and play more often.
From HT Brunch, December 7
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