Comment on Anon considers LASIK

• truthfultemporarily@feddit.org ⁨2⁩ ⁨days⁩ ago

  To expand on that, you make a very small hole by curling your index finger, and look through that hole.

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  • Makeshift@sh.itjust.works ⁨1⁩ ⁨day⁩ ago

    Just tried this and am now reading comments below to learn what the actual fuck. That works. This random internet advice isn’t a lie.

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• shneancy@lemmy.world ⁨2⁩ ⁨days⁩ ago

  just tried it and it work?? how

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  • rtxn@lemmy.world ⁨2⁩ ⁨days⁩ ago

    When your eyes are open and unobscured, light is coming in from every direction. The lens is shaped in such a way that light rays parallel to the eye’s axis are focused on the macula, the center of your sharp vision. A near-sighted (myopic) eye focuses those parallel rays in front of the retina, and a far-sighted (hypermetropic) eye focuses them behind. The farther away the ray is from the eye’s axis, the more it is refracted by the lens, and the more obvious its out-of-focus-ness becomes if the lens has an incorrect shape.

    Corrective eyewear works by refracting the light before it enters the eye and essentially cancelling out the lens’ imperfections.

    A pinhole works by obscuring light rays that are farther from the axis and contribute to the blurry image, only letting through light rays that are near the axis, already aligned more or less with the macula, don’t have to be refracted as sharply, and don’t contribute as much to the blurry image. This is why the camera obscura works, and why apertures in modern photography are used to control both the image’s exposure and the strength of the depth of field.

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  • pitiable_sandwich540@feddit.org ⁨2⁩ ⁨days⁩ ago

    Afaik if you’re myopic, your eyeballs are too long so the plane of focus created by looking at a far away object is no longer on your retina. So i think by looking through a pinhole you widen the depth of field. This means even stuff you don’t focus on is seen sharper.

    I wonder if this also works for hyperopia…

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    • shneancy@lemmy.world ⁨2⁩ ⁨days⁩ ago

      huh! our bodies are so weird

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      • pitiable_sandwich540@feddit.org ⁨2⁩ ⁨days⁩ ago

        Yeah, but not only our eyes/bodies are weird. If you want to know more about weird eyes look up goat pupils (they have horizontal pupils the can rotate 50% to be always level with the ground) or nautilus pinhole eyes (early stage of our eyes with no lense).

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    • captainlezbian@lemmy.world ⁨1⁩ ⁨day⁩ ago

      I use it to read with hyperopia

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      • pitiable_sandwich540@feddit.org ⁨1⁩ ⁨day⁩ ago

        Big spectacles hate this trick!

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    • vala@lemmy.world ⁨1⁩ ⁨day⁩ ago

      Is this why I can see so much better in VR? Smaller field of view? I always assumed it as kind of a side effect of the depth of field hacks they do but FOV would make sense.

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  • ThatWeirdGuy1001@lemmy.world ⁨2⁩ ⁨days⁩ ago

    I learned this is school. It’s because it focuses the light through a narrow passage which increases the details. It’s also how cameras originally worked.

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  • B0rax@feddit.org ⁨2⁩ ⁨days⁩ ago

    Optics.

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• Redjard@lemmy.dbzer0.com ⁨2⁩ ⁨days⁩ ago

  That has limits. Not sure 2hat it comes down to exactly, but under the most ideal conditions I have pulled off yet I’d estimate it improves sight by 3-4.
  -8 with the fov of a pinhole is still blind.

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