Normally, a child is born with little tiny eyes which grow a lot until age 3, then slowly until age 10–12, at which point they’re meant to stop. But if their eyes grow too quickly, or keep growing after age 10–12, or if they’re born with eyeballs that are already a bit too big (usually for genetic reasons — Mum and/or Dad being myopic)…. a child will develop myopia. Myopia, also called shortsightedness, is where far away objects are blurred but close objects are clear. It might seem, on the face of it, to just be another annoying vision problem needing glasses. But myopia isn’t just a blurry vision thing. More myopia means increasing lifelong risks of eye diseases like glaucoma, cataract, retinal detachment and myopic macular degeneration, and even low levels of myopia carry an additional risk. To quote the author of a key scientific paper on these risks, UK Ophthalmologist Dr Ian Flitcroft:
The calculated risks from myopia are comparable to those between hypertension, smoking and cardiovascular disease. In the case of myopic maculopathy [a type of macular degeneration] and retinal detachment the risks are an order of magnitude greater.
I had perfect vision until I was 19. Then, ironically as I was studying optometry, my distance vision started to get worse. First I had to squint to see the number of the bus coming towards me; then I couldn’t see the board in lectures (no online lectures in those days!). Being exposed on a daily basis to computers, as I wasn’t in high school, is probably what started my eyeballs on the growing path again, and I developed late-onset myopia. After a year of worsening, it hasn’t changed to this day, 17 years later. I’ve collected an impressive array of glasses since (owning my own optometry practice helps with this 😉 but it’s wrong to think it’s as simple as just a vision problem.
Now I’m only a little bit myopic — -1.00D to be exact, which means I’m only just blurry enough to have to wear glasses to drive. One dioptre of myopia (that’s our unit of measurement for prescriptions, and if you’re wondering, it’s an inverse metre :D) means that everything gets a bit blurry once it’s more than a metre away, although I can see ok for a few metres. Doesn’t sound like much of a big deal — but it’s wrong to think it’s benign. Even with my small amount of myopia, I have double the risk of cataract, triple the risk of retinal detachment and double the risk of myopic macular degeneration compared to someone who isn’t myopic. Once someone gets to -3.00D of myopia (they can see clearly out to 33cm, and probably ok out to about a metre), these risks increase to 9–10 times greater than a normally sighted person. As Flitcroft makes the comparison, the risk of having a stroke if you have uncontrolled high blood pressure is about three times greater than for someone with normal blood pressure. We’re talking 9–10 times greater risk of eye diseases which can cause blindness, with only moderate amounts of myopia.
Once a person gets to -5.00 or -6.00D of myopia, the risk of potentially blinding eye conditions like retinal detachment goes up to 21 times higher, and myopic macular degeneration risk is 40 times higher than someone with normal vision. This is serious stuff.
So the point of myopia control (the area of scientific research) and myopia management (putting it into clinical practice) is to keep myopia as low as possible, as this reduces lifelong risk of potentially blinding eye diseases. Myopia management involves prescribing specific types of spectacle lenses, contact lenses and even eye drops which have been scientifically proven to slow down the worsening of myopia. We no longer have to sit by and watch our kid’s vision get worse and worse every year — now we can offer solutions to try and change this path.