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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
Nicely put Murray. I am eager to know what they have to say. Also a little suprised they did not foresee this scenario and be better prepared.

voxelmaniam
Level 5
Thanks!
A voxel is a three dimensional pixel!
Murray Foster

TwoHedWlf
Level 11
I don't think it's possible to give you a focal distance down to the inch, it will vary depending on things like how tight it is on your face, the shape of your head, depth of your eyes, all of that effects the position of your eyes and by that exact focal distance.

JustBob12
Level 3
I wear progressives and the "sweet spot" is hard to find and I struggle to get a clear image. It's not bad, but I think it could be better. I tried a pair of reading glasses and they were useless. Then after reading your post, I tried a another pair I use to play tennis which only have the distance prescription. Oddly enough, the stuff that seems closer to you (the bottom menu bar is a good example) seemed easier to read than with my full prescription glasses. Everything else (I tried video clips, Netflix, game...) seemed similar to what I see with the full prescription glasses. My distance prescription glasses (the tennis ones) are older though and the prescription isn't up to date. 

I'm due for an eye exam anyway (last was 2015) so I'll see if I need new glasses. If I need new glasses, I'll be curious to compare the new full prescription with the new distance only glasses.

Thanks for this post, very interesting.

voxelmaniam
Level 5

TwoHedWlf said:

I don't think it's possible to give you a focal distance down to the inch, it will vary depending on things like how tight it is on your face, the shape of your head, depth of your eyes, all of that effects the position of your eyes and by that exact focal distance.


I suspect that the Go's optics were designed to produce a precise working distance based on the display position and a precise eye position. What the eye perceives as being in focus lies on a range of distances from the eye. Also, the majority of users have the ability to adjust there eye focus. I don't have that ability in my eye due to fixed focus implants. So there is some latitude in the eye position but starting with the precise parameters will allow for a more appropriate corrective lens for my eyes. 

A voxel is a three dimensional pixel!
Murray Foster

brentoni
Level 4

JustBob12 said:

I wear progressives and the "sweet spot" is hard to find and I struggle to get a clear image. It's not bad, but I think it could be better. I tried a pair of reading glasses and they were useless. Then after reading your post, I tried a another pair I use to play tennis which only have the distance prescription. Oddly enough, the stuff that seems closer to you (the bottom menu bar is a good example) seemed easier to read than with my full prescription glasses. Everything else (I tried video clips, Netflix, game...) seemed similar to what I see with the full prescription glasses. My distance prescription glasses (the tennis ones) are older though and the prescription isn't up to date. 

I'm due for an eye exam anyway (last was 2015) so I'll see if I need new glasses. If I need new glasses, I'll be curious to compare the new full prescription with the new distance only glasses.

Thanks for this post, very interesting.


I suspect that the reason glasses with distance prescription worked for stuff that is up close is because the distance that things appear in the Go has little to do with the actual focal distance of the Go. Basically the distances between the screen, the lenses and your eyes, as well as the strength of the lenses creates a specific focal distance your eyes are always focused at while wearing the Go, and anytime something appears to be at a different distance it is actually an illusion caused by showing each eye a different image and doesn't actually affect the focal distance. The reason your distance lenses were better for the bottom menu but the same as progressives for stuff that looked further away is probably because you were trying to read with the near vision part of your lenses when you actually need to be using distance vision for everything.

voxelmaniam
Level 5

brentoni said:


I suspect that the reason glasses with distance prescription worked for stuff that is up close is because the distance that things appear in the Go has little to do with the actual focal distance of the Go. Basically the distances between the screen, the lenses and your eyes, as well as the strength of the lenses creates a specific focal distance your eyes are always focused at while wearing the Go, and anytime something appears to be at a different distance it is actually an illusion caused by showing each eye a different image and doesn't actually affect the focal distance. The reason your distance lenses were better for the bottom menu but the same as progressives for stuff that looked further away is probably because you were trying to read with the near vision part of your lenses when you actually need to be using distance vision for everything.


Yes, the focal distance is the same for all of the images displayed in the Go. The stereo pairs are designed so that the eye sees objects that are intended to appear closer with a larger offset towards the center of the scene. This results in the eyes having a larger angular deviation towards the center and as a result the objects are perceived as being closer.
A voxel is a three dimensional pixel!
Murray Foster

haydon_sheppard
Level 3
Still no definitive answer Murray?

voxelmaniam
Level 5

brentoni said:


I suspect that the reason glasses with distance prescription worked for stuff that is up close is because the distance that things appear in the Go has little to do with the actual focal distance of the Go. Basically the distances between the screen, the lenses and your eyes, as well as the strength of the lenses creates a specific focal distance your eyes are always focused at while wearing the Go, and anytime something appears to be at a different distance it is actually an illusion caused by showing each eye a different image and doesn't actually affect the focal distance. The reason your distance lenses were better for the bottom menu but the same as progressives for stuff that looked further away is probably because you were trying to read with the near vision part of your lenses when you actually need to be using distance vision for everything.


Yes, the focal distance is the same for all of the images displayed in the Go. The stereo pairs are designed so that the eye sees objects that are intended to appear closer with a larger offset towards the center of the scene. This results in the eyes having a larger angular deviation towards the center and as a result the objects are perceived as being closer.
A voxel is a three dimensional pixel!
Murray Foster