Fonts appear fuzzy when connecting my Mac to an external monitor I’ve been having this issue for a long time and I can’t get my head around it.

When I connect my MacBook Pro 2015 to an external 1920x1080 monitor, the font becomes fuzzy and I get dizzy within a few minutes. I tried all suggestions on the official Apple forums but nothing worked.

What I understood is that the problem lies with how macOS renders fonts at different resolutions. I am understanding that it has something to do with aspect ratios and the fact that each pixel is represented by 2 physical pixels to give the Retina effect.

So my MacBook Pro max resolution is 2560x1600 which gives a 1.6 aspect ratio. A 1920x1080 monitor has a 1.78 aspect ratio. So to my understanding, any external monitor should have a 1.6 aspect ratio to be good for my eyes and to avoid font fuzziness.

I saw people recommending ultra HD monitors but those too have the same aspect ratio as 1920x1080, so how are they supposed to be better?

Can someone please explain what I’m missing here?
You're missing something entirely. There's absolutely no requirement of having a 1.6 aspect ratio on external monitors on a Mac.

As long as you do not configure your displays to be mirrored (i.e. showing the exact same image), then the internal and external monitors are treated as separate displays. The resolution and/or aspect ratio of one monitor has no impact at all on the other monitor.

Regarding the 2 physical pixels for Retina effect, you're also missing something entirely here. An external monitor with a 1920x1080 resolution is not going to be in rendered in Retina mode. That is only for high resolution displays. Retina is not part of the equation here at all.

I would ensure that you have chosen font sizes that are large enough for the display. This should cure "fuzziness". You might also want to double-check with a different monitor to ensure that it is not this specific monitor that has a problem.