Watching images on a flat screen (as in any flat surface screen, including CRTs) for prolonged periods has a deleterious effect on a child's vision, and eventually leads to nearsightedness and issues shifting focus, according to eye experts in the US and UK.
Professor Andrea Thau, spokeswoman for the American Optometric Associations, advises:
Children need appropriate visual stimulation for sight to develop normally. Parents should limit TV and computer games, especially in children under six whose sight is still developing, though the effects occur in older children too.
I guess that explains my problem, or part of it, anyway, though I'm extrapolating out to adulthood as someone who didn't use computers or watch much TV as a child. I have increasingly poor vision as I age, something so trivial as a teenager I didn't bother wearing my glasses most of the time, but which now seems to grow increasingly worse as I spend longer and longer hours either gaming, writing (on a laptop), or reading (often by lamplight, in the evening, in bed).
I'm not blind, but it's bad enough that I need glasses in front of a desktop computer screen a couple feet in front of me. Which has additional downsides if you're into various specialty gear. For instance, I slipped on Natural Point's Track IR infrared-based head-tracking system (it lets you look around inside the cockpit of a plane or other vehicle just by moving your head) and was suddenly all too aware of my glass frames, which obscure parts of your view since, per the Track IR freelook mechanic, it's explicitly tied to the shifting visual field. In other words, when I look around, I invariably end up looking through my frames around the edges.
A few years ago, my optometrist noticed I have problems focusing correctly. He said I "overfocus," which as I understand it, means I look at something like the page in a book that might be X inches away, but my eyes exert themselves focally as if I were looking at something X + 3 or 4 inches extra.
Keith Holland, a leading specialist in children's eye problems who examined 12,500 children's eyes in the last decade, noting an "alarming increase" in problems linked to TV and computer game exposure, says:
Humans are not designed to look at a flat screen for long periods – and this is especially the case for children or infants whose vision is developing – and we believe visual skills are being damaged.
As anyone knows, anything that strains your vision is going to be harmful to it over time. I presume some of my focal issues may be due to extended time in front of computer screens (I've never been much of a TV watcher). The good news is that they make special corrective glasses for focal issues. They only help when you're reading up close (not to be confused with reading glasses, which are different) but I can actually feel my eyes forcibly relax when I slip them on. (Now if only I could be more disciplined about wearing them.)
The bad news, of course, is that the only cure-all is spending less time in front of flat screens, kids especially, be they TVs or computers.
Or maybe that's good news too.
Source: PCWorld Blog