Watching TV very closely probably isn't worse for your eyes than
reading a book at close distances. There is a lot more to it than that,
however. It is recommended that when reading a book, you "give your
eyes a rest" by looking away every fifteen minutes or so, allowing your
eyes to focus on something far away. All too often, when a natural
break comes in a TV program, our reaction is not to look away to give
our eyes a rest, but to flip the channel to another which is not
showing an advertisement. This is not a good habit.
Our eyes are designed to focus at a great variety of distances. To
focus constantly at a short distance can make the lens focusing muscles
get fatigued. The sad fact is that people watch about 6 hours of TV a
day, and if you do that very close to the TV and without ever looking
away, your eyes can get quite fatigued.
There are other reasons to walk away from the TV of course. One is
that it flickers sixty times a second, and may contribute to headaches
if it's the only thing in your field of view. Some TV's also emit a
high-pitched whine at the scan rate, which is also not good for the
headache-prone. Perhaps the most important reason for not watching the
darned thing is that the programming is usually abysmal. You can
probably find much better things to do.
Playing video games is perhaps even worse. Modern
three-dimensional first-person games animate the whole screen. As the
character in the game moves, the background on the screen moves up,
down, turns, and bounces. This plays a dirty trick on our biological
protection mechanisms. One is our sense of balance. We have delicate
components in our inner ear which tell us which way gravity is
pointing, to help us with our balance. We expect, from long experience,
for these cues from our inner ears to match up with what we are seeing.
If these don't match, dizziness and nausea result, as they do in
seasickness and other forms of motion sickness. Taking a break usually
makes the effect go away.
(published on 07/26/11)