Not colorblind (my father was) but I appreciated his brief “old eyes” discussion at the end. I’m 42 and have been using a computer since I was 6. Now I’m both nearsighted (since I was 8) and farsighted (since my late 30s), which means I can’t read without glasses of some kind. Similarly, “light mode” is far easier to use and more legible than “dark mode” despite the recent trendiness of the latter. I can also back up his exhortation to not use the thinnest possible lines for text.
4K monitors have been a blessing, not directly (though they sure are nice) but because they’ve brought good fonts and UI scaling into the general use case.
The research I'm aware of has shown that light backgrounds help people with astigmatism because they cause constriction of the pupils to adapt to the increased light coming in given low ambient light, which brings things into sharper focus for those with astigmatism.
Of course not constricting the pupils is a major reason people like dark mode, and mobile devices have greatly increased the use of screens in environments with low ambient light. I suspect the only good solution is to support both light and dark modes universally.
4K monitors have been a blessing, not directly (though they sure are nice) but because they’ve brought good fonts and UI scaling into the general use case.