Eye strain and IPD issues with my XTAL 5K - any fix for this?

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I recently got the chance to buy a used XTAL 5K unit, could´nt resist and pulled the trigger.

After some time with getting used to the VR Tool Software and getting Steam VR working with my XTAL, I had my real first session with the Headset and encountered some eye strain and IPD issues.
I could only use the Headset for around 90 mins, before my eyes really started to hurt. I felt dizzy and neusea the rest of the day and even on the hole next day.

I set the focus wheel of my XTAL 5K to the point of the for me sharpest picture quality and the for my eye most comfortable position. Also tried the most comfortable IPD value for my eyes.
My XTAL 5K unit has the same lenses as the XTAL 3, which ones solved the most problems people had in the past with the older lens systems from VRgineers, at least I heard that from some other users.

I do not know I can resolve that. I have the same issues with my Vive Pro 2. I never had this kind of issues with my quest 2 but had this also happening with my 8KX, if I did not set the IPD correctly.
On my 8KX I set the IPD to 64.2 mm and could use it for long sessions without any problems.
My normal IPD is 68.5 mm. Tried this setting also on my XTAL but without any success.
I guess this could be related to the binocular overlap? The Vive pro 2 does not have the best binocular overlap, but could not find any informations for the XTAL 5K and the XTAL 3 lenses.

Beside that, the FOV and true blacks of the XTAL 5K are awesome for space games, if I get these issues resolved, I have the perfect HMD for me. Also the 3D effect is much better for me personally than compared to my dead 8KX.

I am open to any recommendations, many thanks!

@Djonko BTW, how went the thing with the prescription lens inserts for your XTAL 3? If I remember correctly, you had some issues with the very short focal distance length of the XTAL 3 and you were in contact with VRgineers to get these prescription lens inserts to get rid of that problem? Was it a success for you? I’m just curious :slight_smile:

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If it is Stereo overlap related @Djonko may have some ideas as Iirc he mentioned you csn adjust the stereo overlap. @stixvr also tried a couple the Xtal models but was unable to resolve his. eye strain.

Djonko mentioned from telling with vrgineers that the general current base design for WFoV headsets with the canting uses a much shorter distance and is likely related.

Though with you mentioning vp2; your likely on the right track with the stereo overlap. Imagine @risa2000 might have some insights.

@VR-TECH likely also a good resource.

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Man I feel for you with the eye strain issue. I had it with all the Pimax wide FOV headsets. I probably tired every “fix” available to us.

I owned the XTAL 5K and 8K (version 2). My XTAL units had the new lenses as well and I had the eye strain with it as well. XTAL offered me software where you could adjust the IPD offsets just like the Pitool had. Of course this didnt help. I tried vigorously to get the issue resolved because I LOVE the wide FOV headsets and wont play VR without. I had to come to terms that it wont be resolved so I sold my XTAL 8k to a buddy of mine here in OKC.

I use my Pimax 5K frequently as I like the colors better than the 8KX. Im betting wont have this ussue resolved with the new 12K unit since @PimaxUSA or Kevin Henderson refuses to acknowledge there is an issue. Since the eye strain issue is not apparent with everyone, but Im sure Ill bite the bullet and buy one when its released just to confirm.

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@Heliosurge That would be very nice if the stereo overlap could be adjusted somehow!
In general I do not have any problems with wide FOV lenses, at least for Pimax HMDs.
I had any Versions of Pimax HMDs in the past and had no issues what so ever (except using the wrong IPD settings and then only on the 8KX)

The thing with my Vive Pro 2 was only sidestep from my recently died 8KX and to have a higher hFOV than most other Headsets. I have to say that I have just recently starting to get those kind of problems with my eyes, in the past I had never any kind of eye strain issues at all, no matter the HMD.
I may test that with my Quest 2 in the coming days just to be sure that I do not have these kind of issues with “normal” FOV HMDs. If that should be the case, then probably my VR Time has come to an End, Hopefully not! That would be for me like a hole universe just died!

BTW @Heliosurge Thank you so much for being so present in this forum and Pimax stuff in general, you are always so nice and helpfull to other people and their problems!

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@stixvr Nice to have you back on the XTAL Stuff! I can remember from our last discussion that you had the 5K and 8K Xtal versions. Good to know that VRgineers have this kind of software for IPD offsets, I think I will get in contact with the support about that, maybe I have luck and this helps me to get rid of the eye strain. I was in contact with them recently, as I had some issues to get VR Tool and Steam VR running with my XTAL 5K, very nice and helpfull support I have to say!

I am in the same spot like you with wide FOV HMDs, I also love them and can not really play simulation games with out them, I does not feel right for me to just have paper roll like FOV in simualtion games. I am a space nerd and therefore love crusing around in E:D with a wide FOV!

Now with the XTAL 5K I personally have some nice things, like the better 3D effect, the nice colors and best black levels you can get and a nice resolution + SDE (sufficient enough at least for me).
Additionally the great performance to run it. It is only the eye strain issue so far which I encountered as a serious problem, anything else is great!

I could have went with a Pimax 5K Oled at the end and saved a lot of money instead of a XTAL unit…
But the horrible SDE put me of from it, I had a while back a PImax 5K Oled version and tried it a few sessions. I could not sacrifice the nice SDE and resolution of my 8KX for the nice black levels of the PImax 5K Oled back then. With my XTAL 5K on the other Hand, the SDE is just good enough for me to make this compromiss. Also the ghosting is far less present on the XTAL compared to the PImax 5K BE version. I am impressed by the SDE of my XTAL 5K, nearly as good as the SDE of the 8KX.

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I had the same issue with the 8KX, where it took me weeks to tune the software IPD offset settings to a degree that the strain was less - it never completely disappeared. I always felt there was an issue with the stereo convergence not being entirely okay. The Vive Pro 2 also gave me some kind of discomfort - I sent it back before I could get to the bottom of the cause.

It‘s actually also what I experienced with the Crystal prototype during the road show last year.

With the 8KX I also noticed, that the lowest possible hardware setting worked the best for me - so setting it to 60 although my IPD is 64. But looking at the fresnel lenses also let me recognize, that in the 60 IPD position the distance between the two centers of the lenses, i.e. the spots at the center of the concentric fresnel rings, still was some 66/67 mm apart. In other words, the 60 mm setting effectively has a distance of 67 mm between the actual centers of the lenses. One of the undesirable side effects of this was that it was impossible for me to have the same item in say a game in 100% focus for both eyes - both offer me a sweet spot, but there was no overlap, they are next to each other,

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The issue with low stereo overlap for some users is eye dominance which can cause a “tug of war” between the eyes, eye strain and headache.

Couldn’t use Vive Pro 2 for this very reason, it was returned after a week for a refund.

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Haha nice that you got an XTAL. They’re awesome headsets, yet hard to recommend at the pricepoint they’re set at. I still love mine though, if you can accept that they’re overpriced and do come with their own flaws, they’re still the best you can get IMHO. I still use mine as my daily driver, just haven’t found anything yet that I like more.

About the eye strain, like others mentioned here, the XTAL’s actually are quite similar to the Pimaxes in quite a few ways. You can configure them in the same ways, although the XTAL has even more options. Therefore as a starting point it’s probably a good idea to look up some Pimax 8kX topics on how to configure the headset. Just as with the 8kX, you should just ignore the IPD values. I have configured my 8kX and my XTAL at different IPD settings than what my IPD really is and they work better.

After you tried all that and did find a somewhat ideal setting, you can configure the stereo overlap with the XTAL, this is what they call the ‘inner FoV’ setting, it’s how much you want your headset to render inside the stereo overlap. If you close your left eye and put your left hand 30 cm in front of your nose and then move it to the left, there’s actually quite some distance you will still see it. If you want to render all that with the XTAL, you can, it just consumes processing power. You can change all that settings BTW in the icon in the XTAL menu in the very far right of your windows taskbar, there’s an XTAL icon and you can change settings from standard to custom and then change all that. Took me a few days to even find that icon, haha, not sure if you have found it already.

Now, if you have changed all those settings, then there’s still, what I consider right now the most important thing in VR, what some other mentions above already. In VR headsets you’re not looking at your panels directly, you’re looking at your panels through the lenses of course. The lenses create a ‘virtual image’ in front of you. So you’re eyes are not looking at the panels but at that virtual image. Now lenses are different in how far away from your eyes that projection is. I talked to VREngineers and they said that wide FoV headsets commonly project closers to your eyes than regular headsets. And this make sense of course, if you move your eyes closer to your monitor then it fills more and more up of the space you can see. However this does cause more eye fatigue of course, since you’re focusing on something that’s closer by. You can do what I did: buy some reader glasses at different strenghts, I think I bought 5 pair, they’re cheap anyway only a few dollars. Remove the lenses and stick them onto your XTAL lenses with some painters tape (that you can remove without leaving residue on your XTAL lenses) and see how things change. This did improve some aspects for me, like eye strain, but introduced some new artifacts for me, like distortion. If you find the right strength you can have XTAL indeed make some inserts for you at that strength, they’re not cheap though I think they wanted $500 and you need to ship the headset of course. One alternative is to visit them in Prague and they can do all those tests with you. Their support is awesome. However I felt personally it’s probably not worth it and I’m still using the XTAL as is, just tweaked it as layed out above and my eyestrain is better, yet still not totally gone.

BTW almost all headsets give me some eyestrain. XTAL and Pimax 8kX are the worst, headsets like the index give me a LITTLE eye strain. The only headset that gave me no eye strain AT ALL is the Varjo. My eyes feel completely relaxed, I can wear that headset for a long time and still nothing. But yeah it does seem there might indeed be a relationship between FoV and eye strain.

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That´s actually a great tipp to try the lowest IPD setting on my XTAL, than the stero overlap should be the biggets for me and also the world scale issues (everything looks to small) I encounterd could be resolved. Will test that in the coming days with a long session of +2 hours, to see if this helps with the eye strain or even eliminate it for me.

I think I will sell my Vive Pro 2, the vertical FOV is really to small for me and now with my XTAL, I really do not have any use case for it anymore. I got two USB Dongles for the XTAL, so I should be able to get some controllers working.

This hole thing with the IPD and wide FOV lenses is really strange. I also had to set my IPD in the 8KX around - 4 mm lower (64.2) than my actual real IPD (68.5) to get rid of any eye strain. With that IPD Setting I can wear a 8KX a couple of hours without any problems. Tried that also on my XTAL, but did not helped much. Maybe the lowest 56 mm IPD setting of my XTAL will do the Trick, will test in the coming days.

I had a while back also the crystal and had some eye strain too with it. Also had problems with a too small world scale, setting the IPD lower did not helped either. For me personally I even liked the FOV of the Varjo Aero more than the FOV of the crystal.

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Haha the VP2 is really the worst money I ever spent, that thing is just horrible IMHO. I basically bought it because MRTV was so positive about it. Lesson learned.

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Nice to have you back again on the XTALs! Yeah at some point I could not resist anymore and had to get one. The thing with my XTAL 5K was a pure coincidence, as someone from this community wrote to me per PM, that he knows the guy behind the Ebay XTAL 5K and that he still owns it. He than hooked me up with the guy and after some conversation and pictures of the HMD I decided to buy it from him. Without him, I would still look for a XTAL 5K, they are now a days impossible to find. Also the price to performace ratio is for the 5K Version I think the best one, exspecially if you can buy it used as I did. VRgineers still are offering the 8K Version but I think the total end price with shipping, taxes, fees and so on will be still around 8K $, much more than I paid for my XTAL 5K. That all was then the main reason for me for to go with the 5K Version.

Yeah I find the little “X” Icon quite fast, as soon as I got my XTAL working with Steam VR. Was strange for me at first that many settings of the XTAL runtime are only accessible while something is actively renderd on the HMD and PC. Usally you can set all important things like IPD, render resolution etc. before you are starting any active rendering on the HMD. But yor are getting used to it rather quickly.

Actually your comments and experiences from my last thread here about the XTALs was the main reason for me to buy the 5K or 8K version, as the XTAL 3 does not have the varaible focus length function anymore. I tried on my XTAL the shortes focus length setting or default setting (Which I guess is the same as the XTAL 3) and after that I can now fully understand your eye strain problems. I only could wear the HMD for around a few seconds, before my eye`s started to hurt a lot. I have rather good eye´s and I can see everything sharp starting at around 10 cm distance from my eye´s, but that focal length is way to small in the default setting of my XTAL. The best setting so far for me is like 50% of the hole span of the focal length setting wheel. With that I feel like that main problem for me and my eyes is the binocular overlap, which I will look into with setting the IPD to the lowest at 56 mm and with the “FOV internal” setting. I think they scrapped the hole thing with the focus length wheel adjustment, to make the XTAL 3 smaller, lighter and to maximize the FOV, which works for some people I guess.

I really appreciate your sharing of your experiences with the XTAL 3, as it helped and will help me to get my XTAL 5K adjusted just perfectly for me, many thanks for that!

I am sharing the same opinion like you about the XTALs, they’re still the best you can get. I am suprised by the clarity of my XTAL, even though you “only” have pentile 1440p Oled panels, the picture quality + sharpness is somewhat very close to a 8KX, at least for E:D I can speak.

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I just bought it after my 8KX died a while back, to see if I will like it and as a potential replacement. But now I will sell it, as I have my XTAL 5K for now. I have to get my wallet pocket filled up again a little after the buy of my XTAL :wink:

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Will look into that also, good thing that VRgineers are offering a manual IPD adjustment software, so I guess I could test for the eye dominance in my case and if I have problems in that direction.

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Well the good news is that that definitely is something that should be fixable. Because my eye strain is nowhere as bad as that. I do remember that when I just got the headset, mine was also pretty bad pretty quickly (few minutes) and I got rid of that with tweaking the options. Which mostly has been trail/error in my case and also based on my 8kX experience, I think they tweak in a very similar way.

My eye strain now is mostly when I use the headset for a bit longer, 30 minutes I can start feeling it, pretty much like with my 8kX. Shorter sessions and I don’t really feel much eyestrain at all, I’m sure you should be able to get to that too.

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Maybe a good starting point is to set your “inner FoV” to the max, so you have maximum binocular overlap, so you know that that’s not a factor anymore. If your GPU is not fast enough, select a bit less “outer FoV”.

Then go from there, follow the tutorials that have been written on the subject on this website, usually means to first find an IPD that works well for you (forget about your ‘real’ IPD!) and then start tweaking offsets from there.

Tweaking it actually is not a fun process, it’s difficult because if your eyes get tired, then even with the right setting your eyes still will feel tired, so that definitely complicates things. And sometimes it takes a while for your eyes to get tired, so ‘tweaking’ that is quite complicated actually

For me though, if my IPD is (way) too low I feel eye strain really quickly and it feels almost as a relief to increase the IPD from there. My IPD is 70 normally, not even sure what my XTAL is at the moment but I do know I haven’t set it at 70 AND I also know that if I set it too low i really quickly get that eye strain like you described.

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With the right focus length adjusted to around half way of the complete possible max setting of this adjustment wheel on the sides of the XTAL, I can wear it for about 45 minutes, before I start feeling the eye strain (with 64 mm IPD setting). I just tested the lowest possible IPD of 56 mm on my XTAL and I felt quickly a great improvement to my eyes! Also the world scale issue is now gone for me! Everything looks now even sharper than before but I do start to see the edges of the displays on the inner part of the FOV. I will test soon if the max setting of the inner FOV via the XTAL runtime will help with that, I hope so!
The hFOV is now a little smaller than before but the sweet spot and the edge to edge clarity got bigger/better for me. It seems now that the main issue for my eyes is/was the binocular overlap, which should be now greatly increased with the lower IPD setting.

I will soon do a longer session with the 56 mm IPD setting and you recommendations (many thanks for that!) to see if I am getting any eye strain at all! If I can wear my XTAL for around 2h without or with little Eye strain afterwards I would be very happy!

I am surprised that 30 mins is a good time for you for a VR Session. Would be way to short for me to really enjoy the experience, exspecially if you have to set up a motion sim and the joystick together with the XTAL each time, as I have to do. I need nearly 30 min each time to set up everything for my flights in E:D. At just only 30 mins at max for a session in VR no matter the HMD used, I personally would seriously start thinking of getting a triple monitor set up instead of running VR. The hole time spent to Set up everything has to makes sense for me personally, If I need 30 minutes for the hole Set Up, I need at least two hours of pure play time to make the hole spent efforts making sense to me.

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Ha, I don’t like the eyestrain of course at all! I was just saying that it doesn’t kick in before 30 minutes. After that it slowly starts to build up. Longer than 1.5 hours is difficult for me but that’s not such a problem, I barely have such time anyway in a day.

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Well, than I am on the lucky site to have a couple of hours time for each VR session, in total 2-3 times per week. I really enjoy and being thankful to have that time!

There we can see how individual VR can be, exspecially time wise.

Did you got the chance to try out the Star VR One? The lenses of the 12K are looking pretty much the same as the lenses of the Star VR One and should offer a great binocular overlap for reducing any eye strain. I heard that the 12K will have a binocular overlap of around 116 degree and should therefore be feeling great for your eyes.

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Update: Today I tried out with some new IPD Settings my XTAL 5K in a 2 hour session and the eye strain issue is now gone for me! Many thanks to all who helped me in this thread for resolving this issue, I can now fully enjoy my XTAL!

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