Is 65 old enough? ;-)

Of course if I take off my glasses, then every monitor looks the same. But with proper correction, my vision is better than 20/20.

With my prescription computer glasses, the difference between low DPI and high DPI is like night and day. I can see every pixel on a low DPI monitor, while high DPI monitors look beautiful to me.

Please, everyone: do yourself a huge favor and get your vision checked and get some single vision prescription glasses if they are called for. It's hard to overstate the difference this will make in your quality of life.

Edit: Not sure why you were downvoted for a reasonable comment. It's true that your vision will get worse as you get older. Even if nothing else goes wrong, you lose your ability to focus your eyes dynamically. The lenses harden up and lock into a specific focal distance.

However, many of these vision changes are correctable. Progressive lenses are a great solution for "out and about" use. You can look up and down to see far and near things. They aren't very good for computer use, and that's where the single vision lenses come in.

It is a minor nuisance to switch back and forth between the computer glasses and the progressives, but being able to see clearly makes it all worth it.

No, this is a huge myth. I’m getting older (42) and my eye sight is getting worse, and I can still tell the difference between 110 and 220. Heck, I could easily tell the difference between 150 PPI and 220 (a hitachi 28” 4K vs. a iMac retina 5K).

Coding without seeing pixels in font rendering is just bliss, it is too hard to go back.

This sort of long-sightedness is usually correctable.

Though I’m dreading the day I have to get varifocals.

Everyone has different vision, of course! If you don't mind my asking, what is your viewing distance to the screen?

One big consideration for me: I'm 65, so my eyes are not able to focus back and forth to different distances like a younger person.

My solution is a pair of single vision prescription lenses, adjusted to the distance to my monitor(s). I need to be able to use the laptop all on its own, so that determines the focus distance: about 20".

Because of that, I also place any secondary monitor at about the same distance from my eyes, otherwise it would be out of focus. I can't go changing glasses to look at a different monitor. :-)

A 24" 4K display works nicely for this, and as I mentioned it's small enough to work really well in portrait mode.

So I have two recommendations for any programmer. If you haven't used a portrait mode monitor, try it out alongside your laptop display. It's a very practical setup.

But more importantly, if you find yourself gravitating toward lower-DPI monitors, it may be time for a vision check and a good pair of single vision prescription glasses adjusted for your monitor distance (again, about 20" if you ever need to use a laptop by itself). I put off doing this for years - I always thought of myself as the kind of person who "didn't need glasses."

When I finally got the prescription lenses, it was a real eye-opener - pun intended!

The CRTs looked better because there was more "bleed" from pixel to pixel. A great example I found to describe it was if you were in the iOS ecosystem when the iPhone 4 came out, every outdated iOS app looked terrible. The 4 had the same screen size but double the PPI of the previous generations. An outdated app looked better on a <4 than it did on a 4 because the bigger pixels of the earlier phones bled into each other more while the 4 created crisper edges that were incredibly jarring.