Feel Cross-eyed?



Was about to do a drawing to illustrate the problem for those with a large IPD this could be less a problem but for average joe we’re more close to a real fish eyes vision. I’m Wandering about long term vision degradation


My Real IPD is 65mm. But I see better with 66.4mm. But when I Measure the fresnel lens, between centers of concentrics rings, the distance is 74mm.

I can’t use my real IPD, then I tried ALL of the possible options, to find more or less what works better for me.


Well VR in general probably not good for eyes in the long term tbh.


That is exactly the issue I am struggling with too. My IPD is 64 (32 left / 32 right) and no IPD setting on the Pimax will make it truly comfortable. The best I can get is when I dial down to 60, the minimum setting.

I tried a lot of tilting etc… Still need to try twisting the 5K+ a wee bit (bend but not break) to see if that will improve things (though it would not be something one could easily fix for regular use).

I am waiting for a. ew small pair of prescription glasses which should fit well under the 5K+ to help me see sharp at approx. 1 m, I am farsighted. May possibly help a bit too.


Flinnt your point may be exactly what is happening. When i first put it on there was a stretching feeling or something odd about the image. I couldn’t place it because the image looked correct. The feeling faded quickly but that may have just been my brains reaction to make it correct. I have never had the same feeling even with adjustment of the IPD.


What it’s the distance between centers of concentric rings when ipd is set to 60 (on screen)? I’m thinking the lenses are too far apart. When I look at my vive with the correct ipd the lenses are very close together.


Following @Flinnt thoughts, I would say that there are much more potential “points of failure” in Pimax than in a “regular” HMD. First the detached screens from lenses mean that any IPD correction has to apply a correct image shift on the panels. This might not be trivial when considering the sensitivity of the IPD rocker.

Second, when I look at my 5k+ I can see that the angle the lenses keep does not correspond to the angle the casing suggests. Considering that Fresnel lenses are basically flat then their surface should be perpendicular to their optical axis, it may as well be that the lenses are not completely parallel to the panels.

Third, moving lenses for setting up an IPD moves them also closer or further to the eyes thanks to the fact they are slightly canted. Increasing puts them closer, while decreasing puts them further. If we assume that regardless the different IPDs people have their eyes at the same “depth”.

Which is not true, so there goes a fourth. Someone can have the eyes deeper (than expected) and also a narrow IPD so he may (depending on what the design can accommodate) find himself outside of the working zone (or vice versa, someone with protruding eyes and high IPD will face the similar problem on the other side of the zone).

Fifth, imagine looking aside, for example to the right. Your right eye is looking probably right through the center of the lens and the path to the panel is short, while your left eye is looking through almost the outer rim of the lens and takes the longest path to the panel, because of the configuration geometry. How is the brain supposed to deal with that? Looking at the same object, but with each eye focusing differently. Then looking at the other side makes it completely reversed.

No wonder the brain complains or simply rejects it outright.

While Pimax seems to have much larger sweet when worn right (according to my observation), it is very sensitive to vertical placement and a slight change makes the image blurry, even the tilt must be precise to get the clear and sharp picture.

Now, considering the complexity of the optical system of Pimax HMD and the “precision” of the IPD rocker, it may need a level of distortion correction, which is simply not achievable with the available technology. Or, as others already noted, maybe the design itself is not robust enough - in the purely engineering way - it does have very narrow operating zone, where the picture looks right, and once outside of this zone different deformation or focusing problems start to show.

I must admit that after writing all this it starts looking like a pure luck that Pimax works (for some).


Well considering there are a lot of headsets that have zero physical ipd movement and use 100% software to set ipd, i’d say it’s not as bad as you think. There are issues and it’s possible that using foam that lets you change the distance to your face might help a lot of people. I do question the physical distance between the center of lenses not matching real world IPD. This could cause issues


Indeed just needs to be balanced between physical & software.


That is exactly what I am going to look into this weekend.

I have now sold my Vive Pro + WAK and my Rift, but I will forever hold on to my wave 1 minute 4 OG Vive for sentimental value. I will set it up again, dial in the correct IPD and then measure the actual distance between each lense’s very center in order to then set the Pimax to that measurement and hopefully derive an actually reliable IPD setting.

I do understand the approach to just dial the IPD up and down until it feels ‘right’, but I’d rather have one fixed variable against which I can adjust face foam, tilt and vertical placement rather than juggling all at once.

BTW, do any of you guys know if someone is working on custom made HMD face gaskets? I’m thinking given the high resolution of e.g. an iPhone X’s faceID camera, it should now be more than feasible to generate a pretty accurate face scan and model that into a printable file. Any thoughts?


Tonight I took a digital caliper and measured my IPD in the mirror, it was about 69mm. I then cut a straw to the same length and set it on the lenses and adjusted the centers of the concentric circles accordingly…the OSD read 62mm.

Now I don’t know if that’s something we should even be doing, but I will say after trying it at 62 so far I seem to feel less eye strain.

UPDATE: I used EyeMeasure on my friend’s iPhone X to measure my IPD precisely since I posted this, my numbers are Close 67.5 and Far 70

GUIDE how to achieve Perfect Real View with Pimax IPD compensation
@Pimax, will you fix the IPD reading discrepancy in Pitool?
Pimax 5k & 8k Directory

That’s an interesting observation. It sounds like at some (or all?) headsets might be displaying the wrong IPD.

I think I’ll use that measuring tip, if I have any problems with my 8K, once it finally arrives.


It could also mean that Pimax has the lenses offset to the pupil centers to compensate for the large FOV.

@PimaxUSA could you explain how exactly set IPD relates to the lenses positions to avoid people jumping to the wrong conclusions?


Which headset did you receive?



Loving it so far mostly, while filling the annoying min character requirement here…


Here’s a tip: The Emoji text counts towards the limit, so just use a symbol with a long name, like… : stuck_out_tongue_winking_eye : :stuck_out_tongue_winking_eye: …or similar, to reach your 20 char limit instantly.

Also, you can add a bunch of dots, but only 3 will be displayed.


Or they could just remove the bug.


It’s intentional of the forum software to keep folks from posting minimal messages. I don’t think the dev put an option to control 20char min.


I do notice if i push the hmd away from my head a little bit it does help somewhat with ipd issues. My ipd is 62 and I need to bring pimax down to 60 and it’s still off. In virtual desktop it stands out. In one eye text is perfectly clear, the other eye it’s a little blurry. If I move the hmd away from the blurry one (to the left) it gets clearer. They are going to need to get software adjustment to help with this.


I have the same problem; maybe because we have different degree of vision between our two eyes ?