5-minute Myopia with Dr John Phillips

Eyevolution spoke with Dr John Phillips, principle investigator of the Auckland Myopia Laboratory at the University of Auckland. He cleared our view of short-sightedness.


What is myopia?

Myopia is a condition of the eye in which people can see clearly at near but when they try to look in the distance everything seems to be blurry. We’re not sure why it develops, but it certainly develops in a relatively large number of people, in children particularly.

Who gets myopia?

There are a number of different stages. Some people are born with myopia and they have myopia for the rest of their life. Most children, if they’re going to develop myopia, they develop it at the age of about 8 or 12. In fact, a significant number of people develop myopia when they’re over 30, but predominantly they develop it as a school child.

Why do people develop myopia?

There are actually a very large number of hypotheses! One of course is that some people have a genetic susceptibility to developing myopia, if they’re put in a particular environment. At the moment people think that it’s something to do with too little time spent outdoors and too much time spent studying indoors in relatively low lights levels, and things like that. There are lots of pieces of evidence that suggest it’s the environment, not the genes. This huge increase in the prevalence of myopia has only come about in a couple of generations, so it’s highly unlikely that the gene pool has changed that much, whereas the environment has changed hugely for many people.

Describe the progression of myopia.

Typically an optometrist would see a child at say 8 or 9 or 10 because they’re complaining that they can’t see well enough in class to take part or they can’t recognise their friends across the street or something like that. Initially the severity of their short sight is not terribly bad so they would have rather weak spectacles to correct it. Typically what happens now is that they’d be given a pair of spectacles and they’d be sent away and they’d be seen again in 6 months time, and almost inevitably their myopia would have become worse and have to have more powerful spectacles than they’d had before, or contact lenses. And this would go on until perhaps they’re 18 when they’d stop progressing and the severity of their myopia would even out at a constant degree of myopia. And that may be anything from very mild to quite severe.

Can you predict whether someone will develop myopia?

The straight answer to that is no, but we can guess who is likely to develop myopia and who isn’t. A child who has both parents who are myopic is more likely to develop myopia than someone who doesn’t have parents who are myopic. There’s been some work looking at the shape of the eye as to whether people are more likely to develop myopia depending to the particular eye shape that they have, but that has actually not proved to be a reliable way of predicting whether a child will develop myopia. So at the moment we don’t have anything more than that.

How many people get myopia?

In America and Europe the prevalence is about 30%. In Australia, and therefore presumably new Zealand, the prevalence is less than 20%. But in some Asian centres, some studies have shown that 80% of young people are myopic, so it’s hugely variable. In underdeveloped countries the prevalence is very very low, something like 3% typically.

Do we currently have any treatments for myopia?

Not really, we don’t have treatments. We manage myopia by correcting it so that the blurry vision goes away, and at low levels of myopia that’s actually reasonably successful. Adults can receive laser surgery that can permanently correct their vision, like wearing a permanent contact lens on the front of the eye. But these management schemes—contact lenses, spectacles—they just correct the myopia, they don’t actually treat it at all, because the fundamental problem is that the eye too big, so basically what they do is to correct the refractive error. "For some people it is potentially quite a serious issue, but for society it’s a widespread issue."

How big a problem is myopia for New Zealand in general?

We think that a little less than 20% of children in New Zealand have myopia. Well that’s a pretty high prevalence of any sort of condition, and consequently it’s an expensive burden that’s born by a significant number of people in New Zealand. So just from the social economic point of view, it’s a burden. It limits career choices. You really can’t be a pilot if you don’t have good vision, and we’re talking about low levels of myopia. Significant number of people have high myopia, and high myopia is a medical condition that can lead to sight loss later in life. I should say that even low levels of myopia are associated with increased risk of glaucoma and cataract. "It’s bad news really all round."