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Weird focusing phenomenon with eyes while using VR

GlaidrGlaidr Posts: 44
Brain Burst

Hi Everyone, 

So I noticed a weird phenomenon while at work today. I was using Samsung gear VR and noticed that I had to actively try and focus on certain objects in the play space. Even if I was looking directly at them, I had to actually think about what I was doing, and flex my eyes to bring the object in to focus. 

I had already played with the wheel on top of the headset to attempt to focus the headset, and it was easier to focus on closer objects.

Am I missing something? what is this witchcraft!? 

I have bought myself a Rift, but have not got the headset yet. Will this effect transfer over?


  • xWandererxxWandererx Posts: 386
    Mebee have an eye test? It cant hurt
  • Protocol7Protocol7 Posts: 297
    Nexus 6
    The Rift has a fixed focus, it is like looking at an something about 2 metres away.
  • kojackkojack Posts: 5,599 Volunteer Moderator
    Our eyes have two complimentary behaviours called accommodation and vergence.
    Accommodation is when you focus your eyes on objects at different distances.
    Vergence is when you angle your eyes in (converge) or out (diverge) to see objects at different distances.

    Normally our eyes have both of these tied together, but in VR we have vergence for 3d vision but the accommodation is fixed (as Protocol7 mentioned). This means you need to fight a natural human instinct. Some people find this easier than others.

    (It's technically possible to do per pixel focus to match our accommodation, but it's extremely rare and not commercially available (Nvida have a prototype, that's the only one I know of))
  • GlaidrGlaidr Posts: 44
    Brain Burst
    @kojack Interesting! Thankyou for that! Will I notice less of an effect (do to resolution, framerate or something else), when I use my Rift compared to using the Samsung Gear VR?
  • kojackkojack Posts: 5,599 Volunteer Moderator
    I'm not sure what the GearVR's focal distance is.
    CV1 is around 1.5-2m.
    But overall the effect is probably going to be the same on both.  The rift optics are different though. One thing to note is that the rift doesn't have a focus knob like the GearVR does. On the other hand, the rift has an IPD slider (how far apart your eyes are) which the GearVR lacks.

    The same thing affects any 3d technology (3d tvs, magic eye books, those old view masters, etc, but those usually have less range than VR so it's not as noticeable).
  • benprichardsbenprichards Posts: 3
    I have a similar question which this might answer, I have to have the focusing wheel all the way to the left and even then I still have an issue with the focal length. I have good eyesight so I am totally confident it's nothing to do with my eyes, I also had an eye test recently with good results.
  • hoppingbunny123hoppingbunny123 Posts: 627
    edited January 2018
    The science behind the Fresnel lens technology is it brings the picture shown on the screen to the exact spot in the back of your eye to the macula. The eye macula lets you see things in detail otherwise you see a fuzzy picture.

    Now the way the Fresnel lens work is the rings are on the lens and that is like a magnification power, each ring brings the next ring physically closer to the screen.  That lets the final ring in the center be at the proper distance from the screen. Its this distance from the screen that is what is seen clearly and in focus, outside of that center sweet spot you see the other rings that are at different magnification. And there lies the problem that makes you have to focus your eyes to see the picture clearly.

    By the gear vr not having an ipd adjustment dial, only a focus dial, you can't move the center ring to match your ipd, and so if your ipd is different than the gear vr ipd your macula will be over an outer ring, then you see the picture and the light from the screen goes into the eye at the wrong distance.

    To fix the wrong distance you need to bend your eye manually, which adjusts the distance you see the picture at, to touch the picture to the macula which brings the picture in focus.
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