What causes hyperopia?

What causes hyperopia?

Well, really it’s part of the biological variation we see in every parameter of biology. So, we know that if we measure peoples’ heights, we see a normal distribution. If we measure the lengths of arms, we see this normal distribution. We see the same thing with eyes, but with an interesting additional factor.

We know from the study of aboriginal populations that if people are living an outdoor hunter-gatherer type of lifestyle, in that population all the individuals have great distance vision and some may be long-sighted. So the long-sightedness forms part of that continuum of the normal variation in biology. So at a young age, they’ve got good distance vision, they can compensate for their bit of long-sightedness with effort, they can contract the ciliary muscle, accommodate and flex the lens inside the eye and correct their own long-sightedness at a young age to give a good distance image. Even further for near vision, they will lose the ability later. But in these populations, you tend not to see so much short-sightedness and it is actually incredibly rare.

As soon as you take a population like that, make all the young people go to school and make them start to read all the time, about forty per cent will become short-sighted. So, clearly again, there are some genetic factors making these individuals susceptible to developing short-sightedness.

It is fascinating, isn’t it? Changing that environment they’re living in and the way in which they’re stimulating their visual system particularly earlier in life can have his huge effect in how the structure of their eye develops and changes over the course of their early life or even adult life. For this fundamental thing to occur, for them to become short-sighted, such that distance is blurry and the world in which they’re spending a lot of time working so their study is in focus. They’ve made their optics so powerful that this world is nice and crisp on the retina, but the optics are too powerful for the images out there and they need to wear spectacles or contact lenses or have laser eye surgery to correct that