Page 116 - Miracle in the Eye
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M MIRACLE IN THE EYE
they do need to see at a distance, a set of special muscles pulls the entire lens
back toward the retina. 44
The spherical lens in a fish's eye works well underwater. Because of the
higher degree of refraction (the bending of light) in water than in air, a fish's
lens has to be much more curved than a human's. To produce a clear image,
the lens bends the light a lot more than does a flatter one—such as those in
humans and other land animals. 45
Water creatures are always in danger of becoming food for larger crea-
tures. But they do have a special defense mechanism not seen in mammals:
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