async as I have a feeling that constantly seeing the same interface elements at different sizes can mess up accomodation
this is mostly true, on most screens I deal with this issue, it can also affect how you focus on real-life objects after using the screen too
BUT… in my experience, it seems to be VERY connected to the issue with the false 3D effect which frusturatingly affects so many screens (even as far back as the 2000s, I still feel that effect + see super obvious "forced oversharpening" white halos on a NEC CCFL TN from 2005 connected to a "safe" PC outputting 16bpp…)
the reason why I know this is that on my single truly "safe" screen, LG LP133WD2-SLB1 on IdeaPad Yoga 13, I can set the UI zoom level to any size I want, even super huge, and the distance I focus remains essentially the same. the UI elements focus just as easily.
for example, i can set this page to max zoom, and it's still easy to jump between the massive web page text and regular-sized taskbar without strain.
however, this laptop is the ONLY backlit screen that I can do this on.
the only other screens that work like this for me are e-ink — but this laptop panel is a WLED-backlit IPS (that even has some mild PWM and pixel inversion!) yet somehow feels entirely different from ANY other IPS/TN/VA/OLED I've used — including a few other LG IPS I've tried
on every other backlit screen so far, even a few that I deem "usable" or "mostly flat", the moment I increase the size or a large icon appears… I can feel pressure on the eyes changing and a feeling of "increasing closeness" or having to "learn to focus differently" on different-sized elements, like you are saying. but not on the Yoga 13
TLDR: yep this 100% affects lots of screens, but I have "living evidence" that it's actually possible for at least one backlit screen to not have this issue.
i wish i knew why. my only theory is that I see very little "post-processing / colors bleeding into nearby pixels / additional edge enhancement" compared to what I notice in others