Ask HN: Do your eyes bug you even though your prescription is "correct"?

> I also avoid […] high-index lenses for computer work.

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.

I perpetually rub/touch my eyes. My big fear around these surgeries is weakening a structure such that damage is more likely.

> my biggest issue with the way prescriptions are decided is the "this one, or this one" and they both look equally crappy, and they say "which looks less crappy" and i just pick randomly, because they're both awful. and then it continues, where it's just blurry from there on out.

I had an eye opening (ha) experience once I got pretty deep into 200/300/600 yard high power rifle. I was trying to debug an issue with my 600 yard shots clustering in three places - one cluster right in the middle, another cluster directly left, and a third cluster somewhere else

You set up these camera thingies (https://scattusa.com/) and it shows you an exact trace of what's going on with your aiming, while not using any ammo (recoil hides a lot so you do most practice without ammo).

The left cluster ended up being super obvious: trigger control and problems relaxing, making me physically jump shots over there - you could see lines from the Scatt go right after shot breaks.

The other cluster though was strange as hell. It was just not in the right spot. But it was a singular spot, I had two remaining clusters. There was no movement between middle and other cluster like there was with the left. It just looked like some percentage of the time I aimed at the wrong spot (not that far off, but enough to drop points).

Then one day when lying on the ground for an hour with the Scatt, I started seeing double. I'd blink and it would go away, but by relaxing a lot I could make it go back. The double vision was right where the cluster was.

Then I looked up more info on astigmatism (had >2 diopter astigmatism?), and it turns out it's literally just light refracting into 2+ places instead of 1. And of course the real bullseye people know about this (since in high power honestly we're kinda pretending at it), and they have specialized sights for correcting the axis and magnitude of astigmatism:

https://gehmann.com/en/579-Cylindrical-lens-system-0-2-Spher...

And sure enough, that's like the same thing the optometrist is doing. Except in the context of bullseye you can physically see the 2 bullseyes floating around an axis and then coming together.

I get why they do it the way they do it, because your brain corrects the astigmatism and doesn't let you see double normally, but if you can train your eye/brain to kinda dissociate and see double, you can get a pretty exact correction for astigmatism.

Then I got LASIK and my 600 yard scores went from high 170s/ low 180s to like 195+. Lol.

Don't trust random strangers on the internet!

You should ask a qualified or licensed optometrist or optician or whatever it's called wherever you live.

AIUI:

- you don't adjust CYL

- The amount you add is roughly 0.75, plus an extra 0.05 for each year above 40yo.

For example, at age 50:

Add = 0.75 + 0.05 × (50 − 40) = 0.75 + 0.5 = 1.25

So let's say that this person's regular glasses are -3.25 in each eye. Their computer glasses would be -2.00 in each eye.

Don't trust random strangers on the internet!

Since it hasn't been mentioned yet, I must add this: when we work and focus, especially when using digital screens, we tend to blink a lot less frequently. If tear composition is not good or there are other exacerbating factors (e.g. an AC with high flow), the break-up of the tear film can easily lead to eyestrain and even blurry vision. In such situations, preservative-free artificial tear drops 3-5x a day can lead to pretty good results. In some cases, one needs to try a few, each for a week or two, before finding the correct one. Pro tip: any eye drop can cause discomfort for a few seconds, especially if the dry eye symptoms have persisted for a long time.

Further reading: https://eyewiki.org/Dry_Eye_Syndrome