Yes! You're the first to mention this.
It's not refractive index itself that's the problem, it's dispersion (roughly, the degree to which refractive index varies across the visual spectrum, described by ‘Abbe number’). We've all seen pictures of a prism splitting a beam of white light into a rainbow — for visual purposes, the less split the better.
Higher-index materials tend to have poorer dispersion, but especially in the mid-range 1.6ish, there are wide variations in quality at the same index. Glass tends to be best, if your prescription is light enough that you can handle the weight. Polycarbonate and acrylic are awful. MR-8 is in the middle, and what I've settled on for recent computer glasses.
Here's a good way to test your glass's refraction index. On your desktop find a small red icon with something white in the center. Stare directly at it. Now turn your head until the icon is at the edge of your vision. If your lenses are cheap polycarbonate, the white part of the icon will appear to move towards the edge of the icon or even out of it.
Most non-cheapo glasses today in the US use Trivex. It's a polymer, not glass, but its Abbe number is 43, which is perfectly adequate.
Crown glass, with its Abbe number of 59, is superior, but the eyeball can discern differences only up to 45-50, so most of Crown glass's improvement over Trivex is imperceptible.
This is partly why it's not offered in glasses (again, in the US, at least according to my optometrist). It is also twice as heavy, shatters (polymers like Trivex don't), and scratches more easily.
- high (58) Abbe number
- thick (1.5 index)
- cheapest
Actually buying CR-39 lens might require solving a dark pattern maze of online or offline options, since the cost is so low.
I'd used the same material for my outdoor/sports/driving frames but it's higher density caused them to slide down my nose during activity so the next pair I opted for Trivex.
--
¹–CR-39 requires full frame spectacles, as drilling holes is verboten.
²–Shamir Autograph III, awesome & highly recommended.
That’s why our cone response to the spectrum looks like https://en.m.wikipedia.org/wiki/Cone_cell#/media/File%3ACone... instead of having cleanly segregated red vs. green responses. If it was segregated, we could only focus on red or green but not both. By having a heavy overlap, we can get a sharp focus on yellow. And, the visual system makes the full spectrum work by deriving the red vs. green concepts from the difference between the two cone responses. Blue focus is accepted as a necessary sacrifice.
I suppose that's why r/g colorblindness is so common.
Now I always go for the thickest lenses (which are also usually the cheapest) for this reason. My prescription is -3.75, and there isn't any noticeable difference with thinner lenses.
The lens material you've now chosen actually has the best optical properties out of all the plastic lens materials. Its only downside is that the refractive index is only 1.5 which does mean they will be a little bit thicker than the high index ones.
You could also try a material called Trivex which also has low chromatic aberration while being a little thinner than the material you are using which is called CR-39
What kills me is going into the office where I am switching between glasses. Different rooms with different Zoom screens. At home is much nicer where I just have one big monitor to watch.
I take my glasses off to read my phone most of the time. Technically my primary glasses are progressives but it is nicer to take them off.
Same. I wear progressive lenses and I feel like they do fine as far as being able to read the text on my phone or for reading a book. But I tend to take off my glasses anyway to do these things. I'm not entirely sure why this is since I seem to be able to read the text fine with the glasses. My hypothesis is that I like being closer to the text so that it fills up more of my visual field which helps me mentally focus on the text better.
I'm nearsighted and don't need glasses to see my computer screen clearly at all. But nevertheless I started getting headaches from eye strain.
Went to the optometrist, got a pair of glasses just to reduce eye strain at screen distance. Zero difference in sharpness, but I can work all day long with zero eye fatigue.
It's not for avoiding outright headaches (I don't get vision headaches) but it's clearly more comfortable. It's quite possible that what's pleasant is in part the change of pace - but it is also better adapted for sharpness.
12 inches?
that's way too close
Imagine them lying down or propped up on their elbows with the book on the floor. Then that distance seems about right.
(Or am I totally misremembering something...)
Currently wearing, to look at arms-length monitor screen, add +1.0. Will move out to the porch to read and switch to add +1.5. Will come back to cook and switch to my basic prescription.
I must put on and take off 300 pairs of glasses a day. But I don't care. I can't do anything else.
That almost seems to reduce eyestrain as well, at least for me, as they're still good enough to see everything (I can't read text across the room but I can halfway across the room), just not without some light blur on things, and I seem to have trained my brain to stop trying to focus on things, just let it stay in the blur (at least while I have my intermediate glasses on), and that seems to relax my eyes more.
But the intermediate glasses are super clear for when I'm on the computer, which is a good chunk of the day and where I really need to see nice and sharp, as I'm manipulating things with pixel precision at times (game ui, web ui, board game graphic design).
Thing is, I ignored it for about 10 years and my brain simply ignored whatever signal was coming from that eye. I'd look at things and see no blurring unless I closed my right eye. However, at a certain crossover distance my brain "switches over" because my left eye has amazing close vision and my right eye doesn't. I can actually feel it when this happens, like a physical sensation. No headaches, but it is "odd".
Anyway, I decided to get glasses, and it turns out I need two different prescriptions. One is close up (not longsightedness, it is still a myopia lens). The other is for 1m-∞
The intermediate distance lenses are great and my headaches have vastly reduced - because they were specific for VDU, my work paid for a portion of them.
My wife is getting bifocals for basically this same reason.
Reading glasses work fine when the screen is very close to your face such as a laptop screen. However if it's a separate monitor that's ~30 inches away, reading glasses are slightly blurry which can lead to eyestrain and headaches.
https://www.warbyparker.com/learn/wp-content/uploads/2023/04...
Look into it if you suspect it's a contributor to headaches: https://www.google.com/search?q=computer+glasses+%22intermed...