A View from Christopher Mims
Could Better Displays Prevent Nearsightedness?
Myopia may be caused by insufficient sunlight – could reflective displays and time spent outside be the cure?
Laptops equipped with reflective displays, such as this one by Pixel Qi, could allow more outside time
Update: The answer to this question appears, unequivocally, to be “no.” I emailed an ophthalmologist to ask what he thought of the theory that nearsightedness is linked to exposure to sunlight, and here was his response:
“Known causes of myopia include prolonged reading during childhood, and, in extreme cases such as the high and malignant myopia in Singapore, genetic predisposition. Mild slowing of myopic progression in childhood can be effected by use of atropine and other agents which chronically relax accommodation. Thus, near work, especially reading, seems a confounding variable. Also, several years ago it was found that children who slept with night lights on were more likely to become myopic. (MORE light, not less?)
A repeat of this study did not confirm, however. Also, there is the problem with increased skin cancer in adulthood from excess exposure to sunlight in childhood. I really suspect that more outdoor time will reduce myopic progression, but only because no one reads or does prolonged near work requiring precise focusing in sunlight.”
Vision experts now believe that spending an insufficient amount of time outdoors makes children nearsighted, [Added: but they’re almost certainly wrong] and that it’s all due to the 10x differential in the amount of light their eyes are exposed to when outside. The mechanism appears to be straightforward: light releases retinal dopamine (a neurotransmitter) which inhibits eye growth, and eyes that grow too much become nearsighted. [Again: wrong.]
It’s an appealing hypothesis, and it certainly dovetails with the observation that the more bookish among us tend to wear glasses. (I say that as someone whose entire family is half-blind without spectacles.)
Unfortunately, technology is moving the world’s children in exactly the wrong direction, if our goal is less dependence on corrective lenses, or at least less severe myopia. The core problem is that all of the screens we’ve become so addicted to require us to sit in near-darkness.
If you think the iPad’s screen is “bright,” try taking it outside on a clear day and sit with it in bright sunlight. If you can get over the reflection, your next problem will be that the screen will be almost completely washed out by the intensity of the sun’s rays. This illustrates the incredible range of ambient light over which our eyes can operate, dilating our pupils and adjusting the biochemistry of the receptors in our eyes to compensate.
Here’s where technology comes in: Starting with e-ink, the display technology used in Amazon’s Kindle, a new class of reflective displays is beginning to come to market. These displays don’t just work in sunlight – like the original black and white gameboy, they actually require light in order to produce an image we can see. Just like those other things we used to read… what were they called? Oh yes: books.
Two technologies you might see on the screen of a tablet or laptop in the not too distant future are the full-color Mirasol displays from Qualcomm, and black and white displays from Pixel Qi. There are many others.
What they all have in common, and where they differ from traditional e-ink displays, are refresh rates fast enough to work as a conventional screen, displaying smooth scrolling, multimedia playback and the like.
And here’s where we use technology to try to solve a problem that technology brought about in the first place: In theory, at least, school age children equipped with these devices could use them while spending the additional 10-14 hours per week outside that researchers estimate are required to stave off nearsightedness.
If this sounds like a crazy notion for kids in, say, Michigan, keep in mind that children in northern latitudes don’t seem to be any more likely to need corrective lenses (after you control for the amount of time they spend indoords) – probably because they make up for winters by spending more time outside in the summer.
Instruction, homework and recreational time spent outside is for the first time a possibility when a reflective display is available.
At the very least, these displays could help reverse the trend of eliminating light from indoor spaces just to accommodate our dim, glowing screens. [This appears to be the only positive effect listed in this post that still stands.]