Today I Learned: Humans only see Stereoscopic3D at a < 90° FOV (and why most HMDs aim for this as a minimum)


Having been a Stereoscopic gamer for over 2 decades, I have always taken for granted that humans have Stereoscopic3D vision.

Stereoscopy is [mainly] caused by FOV overlap between both eyes. However, only today I learned that the human eye is blocked by ones nose. I have measured my overlap to be approximately 90 degrees.

This means that my [and likely most people’s] stereoscopic 3D perception is limited to only 90° in front of the face.

I wonder if this is a big reason that most HMDs aim for around this figure as a minimum.

I also ask myself whether high FOV HMDs are as important to me as I previously imagined them to be:

  • If I will not be perceiving Stereoscopic3D in the extra FOV compared to other more ‘standard’ headsets, - a reasonable person would be more reluctant to pay the premium price…

my experience of the pimax headsets so far is that they suffer from poor 3d overlap due to the canted displays, you actually get less “left” from your right eye and vice versa, like suddenly you have a much bigger nose blocking that information, I get better “3d” effect and therefore better immersion from “potato” fov headsets, using a pimax headset feels basically like using a flat screen to me


I wonder if this is a big reason that most HMDs aim for around this figure as a minimum.

No. They do that because wide FOV is hard.

I also ask myself whether high FOV HMDs are as important to me as I previously imagined them to be

With all due respect, this is horsesh*t. Why do humans have close to 180 degrees of vision then?
The peripheral vision is very important for getting additional information about the world surrounding you and adds a ton to awareness and immersion.

Have you used a wide FOV headset before? If not, try one before convincing yourself you don’t need it.


True you don’t see stereo 3d in your full FOV but that extra FOV still aids in giving a sense of place and immersion. The closer we can get to that full human range of FOV in the VR headset then the more real the virtual world can feel. Even though we can’t see 3d in that wide FOV area it still feels unnatural to see black borders around the edge of your vision because that is not what we see in the real world.


for me, pimax adds fov on the outer edges but sacrifices fov on the inside edges e.g. by the nose, e.g. where 3d happens, meaning I get a very poor sense of 3d which means I find pimax headsets worse than “potato” ones when it comes to immersion


For me in my 5k+ I didn’t perceive the 3d effect to be any less than what I experienced in any of my other headsets. I felt great immersion in Skyrim with it.


Extra information yes. Reading a book or sign in the far periphery no.


i think extra information is all there is really, i mean our naked eyes are incapable of reading or see anything clearly in the extreme peripheral vision anyway. Human eye focus point is really a small dot in even in the centre, and peripheral is just that, peripheral.


The human vision overlap for seen in 3D is about 120º.
From Stanford University.


Great article from standford. However, binocular overlap is not the only cause of 3D vision. Yes, it is the cause of stereoscopic 3d. But the way that we focus on objects in VR is completely different than on a monitor. Close one eye in VR, bring a controller up to the open eye. The background blurs. Best we could get to that in other flat games is dynamic DoF, and it’s pure cheese (though I constantly used it in ENB presets in skyrim tbh).

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I’ve never had a problem with the 3d effect of the pimax. Maybe because my ipd is low and I keep it at near minimum capacity of the headset. But find they peripheral essential and even the pimax is not wide enough.


True, but that area is important for detecting motion and a sense of place. I notice flickering strongly, in my peripheral vision area, in real life and VR. The “blinder effect” of a small FOV disconnects me from feeling the immersion effect of actually “being there”.


The vision in your eyes is faster in the peripherals, this allows you to respond to prey or enemies sneaking up on you or running away from you. Your attention is therefore drawn to movement there, this makes driving safer too as you detect kids stepping into the road, etc.
The detail is sacrificed to enable a faster persistence of vision. I guess the brain, not having to process stereo overlap enables the higher speed also.
VR gaming should have a wide FOV for this very reason, so you can respond to enemies in your peripherals and make games more immersive.


The more I think about it the more VR should cover the peripheral vision in the centre of your face, that is the left part of your right eye and the right part of your left eye closest to your nose.
In real life you cannot really see where the stereo overlap ends but with VR headsets you can indeed and the distortion of the edges of the lenses disrupts the central stereo part of your vision. This of course is hard to achieve because of the nose being in the way but I think this part of your peripheral vision is more important than the outer part towards your ears.

sure, having the panels take up the same physical space would be awesome.

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There’s a few things to unpack here —
Regards how human vision works in general :

[ 1 ] First and most relevant to the discussion around FOV is that the eye does not stay fixed. Instead your eyeballs tend to move a lot - and scan a scene with unconscious movements called " saccades ". In order to fixate on objects at different positions and depth in the real world.

[ 2 ] The " act of seeing " also depends on fusing multiple inputs from the visual cortex. While central foveated vision covers only about 2 - 5 ° , and is where we are able to read text or identify symbols and colours. Its an additive process that builds up the mental model of vision.

[ 3 ] As mentioned above " peripheral " vision is largely responsible for the perception of motion and changes in speed. Its something that has evolved in animals - humans over time and changes in IPD also affect sensitivity to scale - distance , speed approximation.

So its not as simple as saying that the inputs outside the 90 ° central foveated area don’t matter. They absolutely do because vision takes in multiple specialised inputs , and is a lot more " plastic " or adaptable in the brain. It still awes me that the images from our eyes - pass through the middle brain ( or " Wernickes area " , the language center ) before reaching the visual cortex.

The world you see before you is a lot more subjective than you think. I’m finding the 140 ° Pimax field of view a lot more comfortable than " Vive " or " Index " where the peripheral information is constrained - or totally missing altogether ? It doesn’t make the image in the center any better but it does contribute to presence.

— CH


Welcome to the OpenMR forum!

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Strange that discussions always turn in a binary argument; is large FOV a good thing? Sure it’s a good thing but at what cost… a 140 degres headset with the G2 image quality, the Index 144hz refresh rate and the valve tracking would probably be the best compromise today…

for the sake of the argument just put your both hands on your head close to your ears in a ways to only block your extreme lateral vision, the thumb and index V around your ears contour. And yes like you said about 140 degree is some kind of acceptable compromise.

The lost of immersion is minimal…

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While it may be true that human vision is not fully stereoscopic at a wider than 90 degree angle, that is irrelevant to Virtual Reality headsets.
It is right there in the name: Virtual REALITY.
Not Virtual Scuba Mask, not Virtual Binoculars, Not Virtual Two Toilet Paper Cores.
So the goal of recreating reality as experienced by humans should be the entire visible field of view, at a resolution indistinguishable from reality, with no screen door, and high dynamic range 128 bit colour.
Anything less than that will be entertaining, but cannot ever really immerse you as though you were “there”.
Pimax is not at that point, but they at least are attempting to move in the correct direction.
Everyone else in the industry is basically saying something akin to “black and white television is plenty good enough, keep buying those”.
If you are happy with your 720p, 8 bit colour, 70 degree FOV headset, good for you.
I want better, personally.


Then buy the StarVr One or the Xtal… or like most of us, VR enthusiasms and manufactured you are constraint by budget and technology. The paste that we want thing to append is also staggering

The occult rift CV1 is only 4 year ago in mars 2016, hardware chip version take about 2-3 year to build and come to market.

What some people (and I’m among those) want is a more balanced VR headset both and price and features in the near future. the Index 2.0 could by the one…

Pimax is stretching to far the FOV feature pleasing some but not satisfying others. Most mass produce object try to avoid such niche market so prices can be kept low or least reasonable to the average VR enthusiasm.

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