[CoastalCoder]

As I get older, my vision gets worse. Even with decent(?) eye-glasses, I don't see the screen quite as clearly as when I was younger.

I should probably invest a little time in determining what maximum screen resolution actually matters to me at various distances.

[Stratoscope]

I'm 71 and still actively programming. One thing I did years ago was to get a pair of single vision glasses set up for my eyes' distance from the laptop screen (about 20"). These changed my life.

I use progressives for everyday activity, but at the computer I switch to the single vision. I have a triple-monitor setup: the 15" 4K display on my ThinkPad P1, and two 24" 4K monitors (currently LG, but I've used similar Dell and ViewSonic monitors in the past).

The external monitors are mounted on Amazon Basics arms made by Ergotron. I prefer the Amazon Basics because they have a matte black finish instead of the silver finish of the Ergotron-branded arms. They are identical otherwise.

One 24" monitor sits directly above the laptop display, with their left edges aligned. The other sits to the left of these in portrait mode. This is ideal for reading documentation, especially PDF files.

I run the ThinkPad at 300% scaling and the larger monitors at 200%. All three are adjusted to be at about the same 20" distance from my eyes. The ThinkPad display is in the usual tipped-back laptop position. The horizontal monitor above it is closer to a straight up-and-down angle (but not quite). The portrait monitor is also tilted back a bit. The idea here is to have the "normal" for the center of each monitor point to my eyes.

It's also important to keep the prescriptions updated for both the progressive and single vision lenses, especially if you are in your 40s when your vision changes more rapidly.

[CoastalCoder]

I appreciate the tip.

I am using single-prescription lenses, and I update them every 1-2 years (via Koch Eye Associates). I order lenses at the specific focal distance of my monitors.

For some reason, in recent years my eyes never feel comfortable with the updated lenses. Not sure if my eyes are getting less forgiving w.r.t. focal distance, or if something is goofy about the lenses that Koch is selling me.

I think my next step is to try another optometrist / glasses-vendor.

Another possibility is that I'm using a big monitor, so the distance from my eyes to the screen-center is pretty different from the distance to the screen-edge. I may just need to try smaller screens or (yuck) curved screens.

[shortcake27]

One possibility to look into is convergence issues. The solution to presbyopia is to prescribe positive lenses. However, positive lenses force your eyes to converge more. So if you have convergence issues, these can make things worse.

This appears to be the issue I have. I’ve been to a few optometrists and they really don’t want to hear about it. To be fair, regular optometrists probably don’t have the margins to deal with problems like this. It really requires a specialist such as an orthoptist.

For now, I just manage best I can. I can only use my reading/computer glasses for a very short period of time before my eyes hurt like crazy. Then I revert to my distance glasses where I can barely read the text, but at least my eyes don’t hurt.

[Stratoscope]

> Another possibility is that I'm using a big monitor, so the distance from my eyes to the screen-center is pretty different from the distance to the screen-edge.

You may be on to something there! About 10 years ago I visited the Google office in Washington, DC to finish up my work on the 2012 general election map. They had a 32" monitor for me to use, and when I put it at the same 20" distance as my laptop screen I had exactly the same problem. The difference in distance from center to edge was too much for me to keep it all in focus.

[tlamponi]

Note that with a high enough resolution to enable 2x (or even 4x) scaling, text becomes much crisper as anti-aliasing isn't messing with the actual color that much anymore.

So, a HiDPI display _might_ make things easier to read/view even for people with a worse vision like you.

[CoastalCoder]

Thanks, good point.

I guess any conclusions I draw need to consider more than just the screen's native resolution. The software-based systems for rending fonts, and graphics in general, would also matter.

As would the screen treatment (matte vs. glossy), since AFAIK all matte finishes add a little bit of blur.

[zozbot234]

Anti-aliasing should not be messing with the color at all. It shouldn't even be messing with brightness and contrast all that much; most common artifacts are due to performing anti-aliasing w/ an incorrect gamma for the display. Gamma-correct and pixel-perfect content makes even a low resolution 768p screen quite usable. And a 1080p screen is crisp enough already that individual pixels are not visible when looking at the whole screen. Anything higher than that is pure overkill.

[fyrn_]

Font anti aliasing, or more specifically subpixel rendering absolutely changes color. It of course does so in a way that is ideally not perceptible, but it is there. Here's an example of an e rendered with subpixel rendering close up: https://upload.wikimedia.org/wikipedia/commons/f/f3/Subpixel...

https://en.wikipedia.org/wiki/Subpixel_rendering

[vladvasiliu]

How do you get this gamma-correct antialiasing in practice?

I see this often on business 24" FHD displays. It's especially atrocious with light text on dark backgrounds. Bonus points for the current fashion of super-skinny fonts, which seem to have different colors for every vertical line.

[barbariangrunge]

You measure your minimum resolving angle as a function of distance, then calculate what dpi that corresponds to. Except, since it’s an angle, distance matters here. So you add in what distance you’ll be from the display.

But I forget what numbers to plug in. We learned that in graphics courses back in uni, and how 4K big screen displays are probably only beneficial as though you are getting super sampling antialiasing

Edit: a quick google search returned:

> The human eye has an angular resolution of about 1 arcminute (0.02 degrees or 0.0003 radians) which enables us to distinguish things that are 30 centimetres apart at a distance of 1 kilometre

You just need some basic trig to do your calculation now, and to modify your resolving number based on some experiments based on your particular eyes

[Dylan16807]

It's more complicated than that. Angular resolution is where you can distinguish between one or two separate objects. You need an entire rod/cone/camera pixel in between to pick out the middle. But when it comes to viewing edges and lines, it's like using grayscale instead of black and white. Differences of position ten times as small can be distinguished.

https://en.wikipedia.org/wiki/Hyperacuity