lookingforlissa

Escape your life for a little while — come play in mine.

Eyes like a hawk

Posted by Lissa on October 23, 2009

I get my knowledge from the most random of places.  I owe any (sketchy) familiarity with the historical religious quagmire called the Middle East to The Source. I helped diagnose my grandmother’s cataracts thanks to The Clan of the Cave Bear.*

And now  — thanks to The Fiery Cross — I’m wondering if I lack binocular vision.

Physician Claire gives her son-in-law Roger a few eye tests, asking him about which sports he played and which sports were difficult.  She then explains the reason that he could play soccer but not tennis was that he has no binocular vision — that his brain never learned to merge the pictures from his two different eyes to form a true 3-D picture.  Instead, he’s learned to subconsciously judge the distance of things by comparing their relative size.  She assures him that he should still be able to shoot, as many men close one eye while doing that anyway, but warns that he might have difficulty tracking moving objects across the sky.

Every single bit of this applies perfectly to me, right down to the preferred and proscribed sports.

I find it just as easy to go about my business with my left eye covered.  I don’t gain any real depth perception by looking at something with two eyes, rather than just my strong eye.

Is anyone else familiar with this concept?  Do you have the same problem?  Do you know how to test for it?

At the end, Claire assures Roger that many creatures, such as birds of prey, have no binocular vision, as their eyes are on the sides of their heads.  So even if it’s true — I’ve got eyes like a hawk.

But that’s not going to help me when shotgunning clays . . .

P.S. Thanks to everyone for holster advice!  And I definitely plan to buy a bluegun.  I’d mentioned to Mike that we need to practice a bit with him trying to grab my “gun” away from me — and that’s not the sort of thing you do with a real gun!

*I noticed that my Japo’s irises were blue at the edges.  Japo, you will recall, is Chinese; we’re not supposed to have blue eyes.  I thought of how, in The Clan of the Cave Bear, the Clan initially thinks Ayla might be blind because she has blue eyes.  All the Clan members have brown eyes; their eyes only film blue when they’re going blind with old age.  Thinking of this, I mentioned it to my mother, my aunt took Japo to the eye doctor a little while later, and they diagnosed her with cataracts.  True story!

About these ads

9 Responses to “Eyes like a hawk”

  1. Tam said

    Heh. I always described Jean Auel’s books to friends as “Half-bodice-ripper, half-Foxfire.”

  2. wolfwalker said

    At the end, Claire assures Roger that many creatures, such as birds of prey, have no binocular vision, as their eyes are on the sides of their heads.

    Alas, this is nonsense. While most birds have eyes located on the sides of their heads, all birds of prey have eyes and eyesockets that are arranged in such a way as to give them a substantial field of forward-looking binocular vision. I’ve never heard of an exception to this rule. If you can stand directly in front of any animal’s head and see the shape of both eyes’ pupils at the same time … then it has binocular vision.

    This, OTOH:

    She then explains the reason that he could play soccer but not tennis was that he has no binocular vision — that his brain never learned to merge the pictures from his two different eyes to form a true 3-D picture.

    strikes me as probably containing at least a germ of truth. Full binocular vision is only possible when the two eyes are used equally. When one eye is much stronger than the other, the brain tends to use the strong eye’s image and ignore the weak eye’s image, which in turn badly weakens binocular vision. There are tests that you can do for this, images that are only visible if you have full binocular vision. They’re fairly standard in eye exams.

    • Mike said

      I think you’ve defined away the chance for anyone to have “full” binocular vision (my understanding was that everyone had a dominant eye just as everyone has a dominant hand, though some are more ambidextrous than others), but I agree with the larger point. In soccer, the ball is big and everything is usually far away and moving at more moderate speeds than in tennis, so parallax problems aren’t that big a deal. In sports with a smaller, faster moving ball, being off by a fraction of an inch can be a much bigger problem.

      • Jeff said

        I don’t seem to have a dominant eye. When I try all of the standard eye dominance tests, the result depends on which side the distant object I’m referencing is. I haven’t yet figured out how to shoot (with a sight focus)with both eyes open without seeing two targets and two rear sights.

  3. Evyl Robot said

    I’ve got a good friend that is blind as a bat in one eye – hence no depth-perception. He also likes to drive aggressively. Those two don’t usually go together, as accurately judging depth and distance is pretty crucial when driving fast. But, I’ve noticed him doing something peculiar when I ride shotgun. When he’s ‘in the zone’ behind the wheel, taking corners and curves hard, and dipping deeper into the throttle, I’ve seen him kind of bob his head side to side from time to time. It seems that he’s learned to judge depth and distance with the reference of one eye due to the lack of vision in the other. I’ve never seen anybody else do anything like that, and find it fascinating.

  4. Brad K. said

    My favorite Auel book was Valley of Horses, then Clan of the Cave Bear. Mammoth Hunters was OK, but started getting tedious, which carried on to the others (Plains of Passage, Shelters of Stone). I miss Whinny.

  5. Jennifer said

    I might have to stop reading your blog. [joke]
    I was wondering around life thinking my eyesight is fine, and now I’m convinced I also do not have binocular vision!

    Here’s a simple test: http://www.vision3d.com/frame.html
    I see one eye/one thumb.

  6. TBeck said

    Due to a childhood injury, I cannot use both eyes simultaneously. If I open my left eye, my right eye wanders off and plays videogames or something. I can still shoot very well, just don;t expect me to catch the keys that you toss to me. I’ve never hit another car while driving. The brain is a wonderfully adaptable organ.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

 
Follow

Get every new post delivered to your Inbox.

%d bloggers like this: