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Dear Kyle:
Is your cat wearing contacts? Got glasses for your guinea pig? Though you've probably answered "no"
to these questions, you gotta admit it can be tough to tell if your pets are nearsighted or
farsighted, especially since they can't talk to your eye doctor the way you can. And it's easy to
see why your animal friends might have vision problems the way people do; after all, they use their
eyes to see just as humans do, too.
While this topic hasn't been investigated in great depth, scientists have speculated on the
need for spectacles among animals. And studies from decades ago show that poor vision has
apparently more to do with your environment and viewing habits than how furry, slimy or scaly you
are! For example, laboratory animals raised in small cages tend to be nearsighted, while most wild
animals seem to have perfect vision.
These findings, in turn, have shed light on how humans get vision problems. Many scientists
believe that nearsightedness, or myopia, is particularly common in today's society because we spend
so much time staring at computer screens and reading. And seeing is believing! As you grow up, the
shape of your eyes changes so that the natural focus of the lens is positioned to produce the
sharpest image on the retina.
That means if you spend lots and lots of time reading books, you'll "train" your eyes to focus
most easily at short distances, causing the eye to develop in an elongated manner. Conversely,
those who regularly focus their eyes over longer distances, such as sailors, mountaineers, and
people who live in less industrialized societies seem less likely to become nearsighted. So maybe
your cat doesn't need contacts because she spends a lot less time reading books and studying for
exams than you do. (And I guess that explains why, in my social circle, the ones who tend to sport
spectacles are real bookworms!)
Signed,
Wendell
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