Anonymous asked in Science & MathematicsBiology · 8 years ago

Why do humans eyesight get weak, but not animals?

Why do we need to wear glasses because our eyesight got weak at various ages?

But u never see animals needing glasses? How comes their eye sight always stays constant? Or that's what I think it does anyway

7 Answers

  • Lucy
    Lv 6
    8 years ago
    Favorite Answer

    Animals eyesight does deteriorate. Look into the eyes of most elderly cats and dogs and you'll see that they're blue with cataracts.

    Obviously animals don't wear glasses because (a) there's no way to find out what lenses they need since they don't speak or read, and (b) how would they keep them on?

  • 8 years ago

    This is not about the back of the eye deteriorating, although that can be a problem.

    Just like camera we have lenses on our eyes and on a camera, if you want to focus on a subject further away you move the position of the lens, but with eyes, instead of having our eyes move in and out, we have 'squashable lenses. Muscles on the eyeball push the lens so it stick out very slightly so we can focus on different subjects at different distances.

    The reason we need glasses is because those muscles in our eyeballs start to deteriorate and cant 'squash' the lens as easily so glasses distort the light for us.

    This happens with animals too, my dog can't see very well and walks into door all the time.

  • Anonymous
    8 years ago

    Both animals and humans have 2 types of eye cells. Cones and rods. Cones help adapt to vision by reflecting light off things like a mirror (this makes an animals eye glow at night. Both animals and humans eyesight deteriorate but humans eyes do faster because they have less rods and cones in their eye cells. Unlike animals, they have many of these cells. Most people don't know it but animals eyesight do deteriorate over time. A

  • 8 years ago

    Those are good answers. Dogs get most of the same eye ailments as humans, such as glaucoma, cateracts, pink eye, macular degeneration, astigmatism, far sighted and near sighted; but fitting glasses or contact lenses would be costly and possibly the animal would be uncooperative. Cats have slightly different eye structure so I presume there is lots of variety over the many species. Neil

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  • 8 years ago

    Animals eyesight does get weaker but obviously they cant get glasses. Instead there is treatment vets can give them or if it gets to bad, they have to be put down. Humans are different and we have different ways of helping our eyes as they get worse.

  • Anonymous
    5 years ago

    Some animals can hear higher an lower frequencies and hear from a smaller amount of auditory stimulation as to why it is because Primates focus mainly on Visual stimuli our hearing and olfactory senses are not as important

  • Anonymous
    6 years ago

    Have you ever used Vision Without Glasses strategy? Move on this site : . This can surely teach people!

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