PSA: Reverb G2 small sweet spots, observations and solutions

TL; DR The short answer is that the SPHERE correction, the 1st column in a prescription is the diopter correction needed for distance vision. If it’s negative, you’re near-sighted. If it’s positive, you’re far-sighted. The ADD column, further to the right in a prescription is the diopter correction needed for close-up vision when your lenses have hardened and can’t be compressed to focus close-up. The ADD diopter is always positive (because you are ~“far-sighted” for near vision if you have presbyopia). Usually the ADD diopter is a correction for about 18 inches of viewing distance. The effective diopter needed for viewing, if I got it right, would be your SPHERE correction added to your ADD correction. So if you were pretty near-sighted, -2.5 SPHERE and +2.5 ADD, you would need a 0 diopter correction to read 18 inches away and be able to read small print on a medicine bottle perfectly without your glasses, if you don’t have significant astigmatism, which complicates things. But the virtual display images for each eye in VR goggles are not set to be 18 inches away from your eyes.

Question for anyone with a filled prescription lens for VR goggles: Did anyone get back from the prescription lens company the actual optical parameters for the lenses made? Would be interesting to see the prescription submitted to the lens company vs. the returned VR lens parameters. Please post if you have that so the rest of us can learn from it, along with your opinion of how well the prescribed VR lenses work in your goggles. I think that I will go with a company eventually that promised to provide the manufactured lens parameters to me.

Long-winded version of how presbyopia factors into everyday vision and VR goggles: For every day glasses, the correction needed for presbyopia is usually placed in the lower part of the lens of the glasses for each eye - the upper part of the lens is for straight ahead distance vision, the lower part is for closer to close-up vision. You’d think a person would get confused but the wearer quickly learns to reflexively move one’s head without thinking about it to have the head at an angle to the desired line of sight to be able to look through the right part of the glasses. For presbyopia, because the eye lens has hardened with age, your eye muscles can’t squeeze the lens to focus it a differing degrees of nearness the way a younger person’s eye can. Therefore, having bifocals for very close-up and distance vision is a black-and-white hack that leaves out intermediate distances. This problem is addressed by having trifocal glasses or even better graduated bifocals where the amount of presbyopia correction increases from the middle section of the glasses towards the bottom (this type of prescription is the most expensive but the best). The wearer again learns to use graduated bifocals with reflexive head movements to get the clearest vision for a desired viewing distance without even thinking about it.

With an HMD, depending on the OEM, the virtual display images are moved far enough from the eyes that a normal seeing person should be able to focus their eye lenses on the images and see them clearly. I think I read on the web that the original Oculus Rift virtual images were effectively at infinity - where presbyopia, the inability to focus close-up, wouldn’t matter. As CptLucky8 points out in his OP, newer headsets have reduced the virtual image distance to 2 or 3 m, effectively, or less. The closer the virtual image is to the eyes, the more presbyopia correction, if needed for real life vision, factors in, and CptLucky8 suggests for the Reverb G2, based on his presbyopia, he figures the focal distance for the G2 is effectively about 1.5 m.

So if you have presbyopia, when you put on VR goggles and the virtual image isn’t all that far away, you’re going to need some presbyopia correction, and real-life glasses are not going to do the trick, especially if they’re graduated because the amount of presbyopia correction will vary according to what part of the lens you’re looking through, designed for different distance viewing, whereas let’s say the virtual display images for the G2 are effectively always 1.5 m away no matter where you look in the FOV. So therefore you might need the same diopter correction for all parts of the display that you want to look at.

In drug stores and Walmart there’s a reading glasses section, often near the pharmacy section, probably to discourage enterprising customers from just donning the merchandise and wearing it out of the store. There are part-frame and full-frame reading glasses of various diopters and a test reading chart whereby you can check out how well with a particular diopter you can read small print close up. If you wanted to try a diopter correction via reading glasses, you wouldn’t want to stand from the chart at the typical reading distance, about 18 inches or so, but stand away at the distance that you think the virtual display might be set to appear.

The problem with using reading glasses is they might not fit in the headset. If the lens abut the built-in lens that the VR headset comes with, the glasses lenses might scratch the VR lenses by rubbing against them, and if you also have astigmatism (non-spherical eyeball), the reading glasses won’t correct for that.

Theoretically, prescription lenses could correct for both presbyopia and astigmatism and obviously avoid the goggle fit and lens abrasion possible problems as they replace or go over the lenses the goggles came with depending on the options for a particular brand and model goggle.

The thing that I don’t understand having looked at several VR prescription lens websites is the blurbs on the website say that the lens made usually use the far distance correction in a prescription, which is not what a presbyopia sufferer wants - you want the appropriate near-distance presbyopia diopter correction to be factored in in addition to the far distance correction just as you would for a regular glasses prescription when looking through the part of the lens designed for intermediate distance viewing.

I asked one of the online sellers about presbyopia correction and got a less than satisfying answer - suggesting that they only planned on going by the distance vision correction and if I felt I needed a presbyopia correction, I’d have to give them my preferred prescription! That’s why I’d love to know, as I requested in a previous post, who got the best satisfaction from what online VR prescription lens seller, particular if the poster needed presbyopia correction. BTW, the response below is from VR Optician - maybe the “front desk” folks are not the same as the guys/gals in the back who actually make the lenses (one would hope!):

We really need oly the far
distance prescription for the adapters. But the best soulution would be
if you test it before. When the headset arrives you can try out if you
like it better with or without reading glasses and the order the values
you feel/can see best with.

Here’s a WikiHow description of how to read your prescription. Any needed presbyopia diopter correction would appear in the ADD column: How to Read an Eyeglass Prescription: 11 Steps (with Pictures) (wikihow.com)

Foster Grant sells “Multi Focus Reading Glasses” with 3 basic diopter corrections for close-up reading, computer screen reading, and across-a-desk viewing. Foster Grant Multi Focus Reading Glasses - Foster Grant.  If you have a base diopter for close-up reading of +2.0, jlacroix of Foster Grant explains in a blog post answer June 23, 2015(see down the page) how the required diopter might change for those increasing distances, according to Foster Grant’s calculations:

Simply put, when you are purchasing Multi Focus readers, order them in the closest diopter you can to what you currently use. The middle area is reduced by approximately half of a diopter from your “base” diopter and the top diopter is approximately one half the strength of the “base” diopter that you order by. IE If you order a +2.00 the 3 areas will be approximately the following diopters:

Top: +1.00
Middle: +1.50
Bottom: +2.00

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+1 for this. I don’t wear glasses, but I frequent the Oculus and Index subreddits. It’s very common to see posts from people saying they scratched their lenses (and their glasses). So be careful if you aren’t using some type of insert.

Does wearing glasses in a headset have a noticeable FOV loss? I always figured I would try to get contacts if I ever needed some type of corrective lenses in case of a lower FOV.

Speaking of what I learned on Reddit, don’t ever let your friends use your headset because it’s inevitable their hands will break your monitor.

So do I…G2 went back ;-(

The best discussion I’ve found so far on how diopter correction for presbyopia interacts with the rest of your eye prescription and is adjusted for varying distances is in a blog post by one “Julie,” who lists no credentials beyond that she has worked “in an eye doctor’s office” (under the About section of her blog). How To Determine The Strength of Reading Glasses You Need - Contacts Advice

She presents a table on how the ADD diopter, which she indicates is for a focal length of 40 cm, should be adjusted for increasing distances:

So jlacroix of Foster Grant (quoted in my previous post) might be a little off in explaining how Foster Grant’s Multi Focus reading glasses work at increasing distance - another front desk person who doesn’t fully know what’s going on in the back?

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Try turning 72

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@JALxml thank you for all these details, it is really valuable information which I’m certain will be helping a lot of people. Your chart is also showing most likely why I’m fine using the +1 in the headset where otherwise I’d need +2.5 at about 40cm!

Here are the glasses I’ve purchased so that it gives you an idea of their size and shape:

Each glass is about 5cm x 4cm:

They fit perfectly into the G2 and I’ve chosen this model because I can unscrew the frame and release the glasses easily should I want to make my own “cheap” inserts (VR Optician is about 6 to 8 weeks long).

NB: they are not the most comfortable to me, especially at the nose and I need to further take time adjusting the pads. I’ve also in the past and unrelated to VR tried the Costco ones (very cheap pack of 3) but they didn’t came close to the Foster Grant cheap ones at the drug store. I also have others Foster Grant cheap ones for day to day use (when working with tools and such, I don’t risk to scratch my regular ones) and I must say this +1 model has neat optical properties edge to edge.

Thanks. I liked your suggestion above to make sure one got a new up-to-date prescription - my current one is about 3 years old so I definitely shouldn’t use that if I go for prescription lenses. Since some folks have said that they’ve had problems dealing with the Connection outlet for the G2 direct from HP, I may very well wait 'til the G2 is available in more places and the queue is not so long (hopefully in not too many weeks). I’ll be following your optical updates closely!

I’ve asked my elder son about his VR Optician Index inserts he has receive a few weeks ago and let you know if there is any info with the lenses themselves. He will confirm me otherwise if looking through glasses or inserts (looking something at various distances IRL) is different or not.

Besides, there could be another explanation using +1 glasses instead of +2.5 inserts: the former is farther away from the HMD lenses whereas the later is really up close. For now this is empirical but this is making enough a difference in solving all the optical flaws of the G2 for me that I’m fine with this for the time being!

In the meantime I’ve started the same topic at reddit and some are reporting this is helping them the same!

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Microsoft has an “Enthusiast’s Guide” for Windows Mixed Reality and down in the Troubleshooting and FAQs section there is a specific new section on the HP Reverb G2.

The part relevant to this thread is that in the FAQ What Should I Do To Get A Crisper Image?, it simply says, amongst other things, “If you need glasses or contacts, you’ll need to wear them when using the device.” Obviously, it doesn’t address the presbyopia question, the correction for which is normally not applied to the entire corrective field in prescription lenses or contacts. But the FAQ essentially states that out of the box, the HP Reverb G2 is made for folks with perfect vision, as I believe is the standard for all Windows Mixed Reality headsets as stated elsewhere in the guide- makes for a cheaper product, literally and figuratively.

Edit_Update: Feedback submitted via the GitHub mechanism on lack of advice on dealing with presbyopia in the Windows Mixed-Reality Enthusiast’s Guide (basically reiterates in part what I’ve posted in this thread): Suggestion on Presbyopia Correction for Windows Mixed-Reality Enthusiasts Guide · Issue #156 · MicrosoftDocs/mixed-reality (github.com)

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First of all thank you for this very insightful discussion.

I got here because I too am having trouble with eyestrain and focus issues with the Reverb G2. To (far) lesser extent with the Quest 2 and Pimax 8kx and none at all with the Rift CV1.

My prescription is nothing special:
-2.0/+.50/105°
-1.75/0/0
IPD according to Optician: 63mm (could be a 20year old value though that just got copy and oasted for decades without re-evaluation)
IPD self measurement (various methods, all resulting in the same): 65mm

Going to see the optician thursday to double check my prescription (only got it a few months back).

However I’m observing the following:

A) Contact lenses: -1.75/-1.75
Nightmare.
A.1) Sweetspot is minimal and text gets blurry on the left and right columns of the [win key]-Overlay and I’m having a hard time even reading the text outside the center column…
A.2) absolutely everything feels too small in VR. Steering wheel and depth perception (too far) is off by a nudge, but enough to cause eye strain.

B) Glasses (prescription see above)
A.1) Sweetspot is WAY better. I can now read columns 1,2,3 clearly and the falloff is way less pronounced than with contact lenses.
A.2) same as above. Everything feels a nudge too small and eyestrain after a few minutes of use. But better than with the contacts.

C) without glasses or contact lenses:
C.1) I can’t read anything, just as blurry as in real life. Can’t say if clarity falloff is vetter as I can’t read anything (lol), but seems the same as B).
C.2) this is where it gets interesting: absolutely everything feels like true-to-life scale. It’s a blurry mess, but it feels like I could grab the gear stick, steering wheel or touch the buttons on the dash panel like in real life. Depth perception is the same - perfect.

This only happens this badly using the Reverb G2. The Quest 2 feels slightly off too, but I have to actively look for it to become perceptible. With the Rift CV1 I can wear glasses without any negative effect at all. It’s just perfect.

Sooo… Any ideas? :smiley:

I’m thinking of just getting prescription lenses from VR Optician and try them out, but they currently have a lead time of about 5 weeks excl. shipping.

Also did some background digging into VROptician (TwoSight GmbH). Their CEOs are one guy that has a masters in advanced computer science, the other one looks like he was in a leading role at Fielmann (big German optician corporation and now runs his own optician business in Germany alongside VROptician which seems to be just a storefront for the TwoSight GmbH alongside his actual optician business). So that at least looks like they have experience where it matters and look like not just being some basement business reselling generic 3rd party lenses.

BTT: any ideas what’s happening in A) B) and C)?

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Are both your contact lenses and your eye glasses relatively brand new (just a few months old?)?

As a former contact lens wearer, I had increasing problems with eye dryness as I got older and older. Have you tried rewetting drops just in case your contact lenses are not adequately wetted? I imagine use of a wetting agent is going to cause more splash from your eyes onto the VR lenses, though. Perhaps the corollary would be that in a closed-up headset with high humidity(?), your eyes could become too wet and the contacts could sag down on your eyes more than they should? Perhaps your optician/optometrist/ophthalmologist could advise you on what might be going on with the contacts vs. your glasses in trying to look at a virtual image.

Hope to have my own G2 by the end of January now so at least I will be able to comment then what works best for me on dealing with presbyopia in VR. If I have a problem, I will probably get a brand new prescription (after I get vaccinated for COVID!) and go for prescription lenses for the headset, too. Right now I rank staying socially distanced as being more important than trips to dentists and doctors of any sort unless it’s really necessary.

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After reading this thread, as well as some other tests I’ve been doing, I now think a new prescription will probably not help me with my perceived bluriness inside of my G2s. That said, it’s been so very long, and when these things change slowly, you have a way of not noticing them, so I think I’m gonna get checked anyway, and either get whatever script they end up writing, or go with the scriptless if for no other reason than to protect my lenses from scratches.

When it comes to the IPD distance (which I currently do not know), are there any tips when it comes to setting it manually, which is what the G2s both offer and require? What visual cues should I be looking for to know I’m at least in the ballpark? I’ll have the dr measure them, and even before that I’ll see if we have a ruler around here or even buy one if not so I can get something more scientific than “I have no idea”, but I thought just jumping in and setting it in realtime might be at least somewhat helpful, but like I said, I don’t know what I’m looking for.

TIA for any assistance!

This forum is full of some really smart people.

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There are lots of articles on the Internet about determining interpupillary distance (IPD). Here’s one from the Road To VR site. The article is intriguing as it suggests first using the recent iPhone/iPad front-facing TrueDepth camera system and a free app called EyeMeasure as well as a host of other methods as alternatives. I’ll have to see if I can talk my wife into installing the app on her iPhone XS Max to get my IPD!

How to Measure Your IPD for VR Headsets and Why It’s Important (roadtovr.com)

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I only use “daily lenses” (the ones you throw away after one-time use). In real life they turn out like 20/20 vision, same as my glasses. In VR it makes a big difference for me.

But apart from the the clarity what annoys me most are the “world scale” issues I’m getting while wearing contacts/glasses. I always contributed it to some OpenVR/WMR bug, but I’m not entirely sure that’s the case anymore. (There are bugs with world scale and OpenVR/WMR but maybe the main contributor here actually are optics).

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When I was reading the article on determining IPD that I cite in my post just above yours to which I’m referring here, I was struck by the author’s comment that not getting the IPD right for one’s VR headset might have an effect on perceived visual scale:

Since we always see the real world from the perspective of our own IPD, correct alignment in a headset is important for matching our ingrained sense of 3D depth and scale. If the IPD of your headset is incorrectly set, the scale of the virtual world will appear to be slightly incorrect.

Sounds like your problems with perceived scale are a bit more than “slightly incorrect” but I wonder if your effective IPD distance with contacts vs glasses vs nothing might be at least part of what’s going on? Unfortunately, in college physics I got to skip optics to take an honors course in electromagnetism! Now I regret that decision! (54 years later!).

That’s the reason why I will let them re-measure my IPD. I had the 63mm measurement on my prescription since I was 10 or so. But PD can change up until your mid 20s from what I’ve read and all my self-measurements come out at 65mm (no matter the method, either manual or various apps) and I also see clearer at the 65mm IPD setting in the CV1.

The other thing is why I think there’s a bug in WMR/OpenVR somewhere:

I also have a Quest 2 and I can see the following in realtime (I can also see the same on my Pimax 8kx, but their IPD numbers are totally off/a lie so I’m focusing on the Q2):
Setting 1, 58mm) world blows up big, everything feels too big
Setting 2, 63mm) just about right, maybe a little too small
Setting 3, 68mm) everything feels like a toy

Doing the same on the Reverb G2:
Min, 62mm) I can see the view slightly shift if I close one eye, everything too small
Mid, 64mm) still everything too small, can’t see a difference in perceived scale, onlz see a slight change when I close one eye
Max, 68mm) doublevision and eyestrain but still everything too small

Going directly from 60mm to 68mm I almost see no effect of perceived scale (in matter of fact I don’t see any. I only know that there is a change because I can see the virtual camera shift ever so slightly when closing kne eye). The only difference is the amount of discomfort.

So there’s either
a) a bug in the render pipeline where the camera positions are off
b) it has something to do with the focal distance of the Reverb G2 being noticably different than every other HMD I own, which also is kind of what this thread speculates about
c) my (real life) optics are broken

About IPD and perceived scale, I’ve posted extensive details in this wish list post, please vote!

[FEATURE REQUEST] Cockpit Size and World Scale in VR

@BernhardBerger Here is how you can see the G2 hardware IPD is working (excerpt from the link above):

Here is an easy test to see this in action with WMR Headsets (at least with the Reverb G1 and the G2):

  • In the Mixed Reality House, go in front of the Halo helmet, up close (really close).
  • Open the WMR settings popup window in VR where you can adjust IPD in software.
  • Grab the slider with the VR controller and while depressing the trigger look toward the helmet.
  • Move the controller to the left fully and wait 1 sec or so, then move to the right fully and wait 1 sec or so.

In doing this you should perceive the helmet is changing size in front of your eyes (for me with an IPD close to 64, there seems to be about 3 distinctive sizes corresponding to slider left, center and right positions).

I see the same as you too in FS2020 when adjusting the IPD slider except I perceive a small change nonetheless, but not as dramatic as it is expected or as effective as with the Index for example. It might just be a WMR OpenXR driver bug (not a WMR bug). There is for example another IPD related bug with WMR for SteamVR where they are rounding the IPD value to the first decimal only… They are aware of this one though.

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Do you by any chance have links to the GitHub issues you mentioned for OpenVR?

I could only find the one kown bug with the inverted panel offsets from the …Raw() method.

This whole issue really is annoying and gets really visible if you happen to have a Oculus device for direct A/B comparison. Their SDK seems to have a vastly different implementation which seems to be spot on.

What’s even more annoying: I have ZERO clue where to report WMR/WMR for SteamVR issues. On OpenVR there is the GitHub (where issues get ignored for years nonetheless, see the display offset bug that’s been around for several years…).
I want to file a bug report, but I can’t seem to find where exactly there’s the right place for it to get acknowledged…

In it’s current state WMR/Reverb G2 is unusable to me.

I didn’t find this “inverted panel offset” known bug??! Can you post a link?

As for reporting I’m with you. It seems there are no particular means to do so (I’m sending you a PM)

It seems that I’m not allowed to post links in this forum/thread, so I’ve sent you a PM…

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