cancel
Showing results for 
Search instead for 
Did you mean: 

Getting the right prescription for lens inserts or Go dedicated glasses

voxelmaniam
Level 5
This thread is a continuation of one started by user haydon.sheppard here:
https://forums.oculusvr.com/community/discussion/comment/613239#Comment_613239

Summary
Not everyone has the best visual experience when first strapping on the Oculus Go. Some users are reporting an inability to get a clear, focused image on the Go display. Barring some fault in a specific Go's assembly most if not all of the focus issues boil down to one or a combination of four things.
1) The Go headset is incorrectly positioned in front of the users eyes.
2) The media content that is being viewed is out of focus or low resolution and thus appears blurry.
3) The user's eyes require corrective lenses and they are not being worn.
4) The corrective lens inserts or glasses worn by the user are unsuited to the optical working distance of the Go.

This discussion will focus on item 4.
The Go can be worn comfortably with glasses but depending upon an individual's prescription a particular set of glasses may not work well with the Go's optics. The case in point that has been under discussion in the thread mentioned above is where the prescription being worn contains a progressive or no-line bifocal configuration and the user's eyes also have fixed focus lens implants as a result of cataract surgery. The particular lenses being worn allow a mixture of focal distances depending upon the vertical angle of view: Straight ahead - distance focus, angled down - near focus. Along with other factors related to the manufacture of progressive optics this causes a significant narrowing of the visual field that can be seen in focus. This means that the eyes can't be rotated to see other parts of the scene. Rather the head must be rotated to see other parts of the scene in focus, for example when reading across the page in the browser.

The solution to this problem is to get single focus glasses. However, for for optimum performance with the Go they should be prescribed for the Go's optical working distance. That is the apparent distance that the Go's optics simulate when when you look through them. For a young person that requires corrective glasses, with natural lenses in their eyes, the distance vision correction prescribed by the eye doctor is sufficient because their eyes can accommodate to the Go's optical working distance. For older users such as myself and particularly because I have fixed focus lens implants, a prescription must be calculated specifically for the Go's optical working distance.

My quest for the right prescription started with my eye doctor. He said that he would have to know more about the Go's optical working distance to write a prescription. I then went to Frames Direct, Oculus' provider of choice for lens inserts. They said they didn't have that information, they worked only with the distance vision prescription and referred me to Oculus support. At first Oculus support referred me to my eye doctor and Frames Direct but with additional (repeated) explanation they are looking deeper (higher) for information about the Go's optical working distance. Cybereality has suggested that the optical working distance is in the range from 1 to 1.5 meters. I'm hoping for something a bit more precise, say within plus or minus 1 inch.

Stay tuned...
A voxel is a three dimensional pixel!
Murray Foster
36 REPLIES 36

haydon_sheppard
Level 3
Sorry Murray. Not used to these forum things. Lol. Yes it was directed to you. Thanks for you’re reply. Is it worth me contacting WimoVR? I’m now even more confused about the viewing distance for the Go. I just think my trip to the Opticians will be trial and error until we find the sweet spot. At least it’s a free eye test.

voxelmaniam
Level 5


Sorry Murray. Not used to these forum things. Lol. Yes it was directed to you. Thanks for you’re reply. Is it worth me contacting WimoVR? I’m now even more confused about the viewing distance for the Go. I just think my trip to the Opticians will be trial and error until we find the sweet spot. At least it’s a free eye test.



No problem. As I mentioned, after explaining my eye issues WimoVR said the distance vision prescription was what they used. It certainly can't hurt to ask.

At this point it seems like I'm left to trial and error to find out what works best. My next move is going to be ordering a pair of glasses online from Zenni Optical that are my single vision distance prescription. I can get them without any bells or whistles for about $17. This will give me another data point. If they give me good results then I will probably spring for the inserts because their positioning will probably allow them to give the best field of view. I will keep you posted.
A voxel is a three dimensional pixel!
Murray Foster

Ravenger
Level 4
I find funnily enough that my VDU distance glasses (about 1m/3 feet focus) seem to work better than my distance glasses with the Go. It just seems less straining on my eyes, and I find the focus is sharp enough to actually make out the display pixels if I look for them. I have WidmoVR lenses for my Rift with a distance perscription and they are fine, good focus with no eye-strain. If I use my VDU glasses they are less clear. So it seems to me the Go's focus distance is closer than the Rift's (though of course I could be wrong). The Go's fixed IPD may also be a factor.

haydon_sheppard
Level 3
Thanks Murray and Ravenger for your input. I will update this forum with my findings after the visit to the optician. If you don’t mind I have one final question? My viewing experience on the Go is a narrowish centre portion which is reasonably in focus with upper and lower parts of the screen blurry. Also if I glance left and right the image is also blurry. I am assuming this effect is a result of my variofocals. Can anyone else wearing variofocals confirm this? Thanks.

Ravenger
Level 4
It's not a varifocal issue - it's a natural consequence of the way VR lenses work. There's always an in-focus 'sweet spot' in the middle and blurrier edges with chromatic aberration (However the Rift compensates for Chromatic aberration, the Go doesn't, due to the GPU power required).

However wearing Varifocals will make the image even more blurry with a smaller sweet-spot, due to the graduated focus distance in the varifocal lens. You need to wear fixed focus glasses with the Go and the Rift. However what the actual focus distance actually is has not been revealed by Oculus officially. Most people find their distance prescription works just fine.

One of the benefits with the fixed focus distance in VR is that people like me with age-related Presbyopia (long sight due to lens inflexibility) can read things up close without having to switch glasses or wear varifocals. B)

voxelmaniam
Level 5
I've received some information about this in a private communication. I've asked for permission to post it to the forum but haven't heard back yet. However, based on the content of the message I think the distance vision prescription is the best choice for now. Ravenger, what does VDU stand for?
A voxel is a three dimensional pixel!
Murray Foster

voxelmaniam
Level 5


The targeted focal distance at the center of the frame for Oculus Go is 1.3 meters. The focal plane of the virtual image is not a flat surface but a curved surface, so the focal distance varies based on factors like eye rotation, the visual field and manufacturing tolerance.



So this is the information we have been seeking. At 1.3 meters (~51 inches) I think we are getting into distance vision territory. I will be seeing my ophthalmologist on Monday and I will get him to advise based on this information.
A voxel is a three dimensional pixel!
Murray Foster

haydon_sheppard
Level 3
I hope the following will be useful to those of you considering prescription single vision glasses for the Go.
i visited my local Boots optician here in the UK yesterday and explained my requirements. This was the first time they had dealt with this sort of request so was not straightforward. I undertook the normal eye test for my variofocals but later explained it was specifically single vision for the Go I required. This presented a few challenges. Working with the 1.3m focal distance supplied by Oculus the optician did his best to work out a prescription but I was unable to use their device whereby you can slip lenses in and out of their device due to it being too big to fit inside the headset. This left us with no alternative but to measure the focal distance with a tape measure and use posters on the wall with different size type to establish roughly the prescription.
Previously with my variofocals the centre portion has always been the best viewing experience so that’s what we settled for. Still a bit hit and miss but they did explain that there was a certain amount of tolerance behind and in front of the optimum viewing distance.
So, where do I go from here? If I buy from Boots the minimum the glasses will cost is about £70 but I have the flexibility to be able to return to them if they prescription needs tweaking. I have to say the optician was brilliant.
I have decided to order online with Glassesdirect which will cost me £35. They have a 7 day return policy so I’m prepared to take the chance. I did consider WidmoVR but it’s a lot to risk if the prescription is not accurate. 
I hope this will be helpful to others and am happy to answer any questions I may not have covered. When I receive my online glasses I will post an update.

Ravenger
Level 4


Ravenger, what does VDU stand for?


Visual Display Unit, or more colloquially, a computer screen.

Ravenger
Level 4
Thanks for the info that the focus distance is 1.3m, so that would explain why I find my computer glasses with a 1m focus distance more comfortable than my distance glasses.