"FWIW, I've tried dark mode and have to enlarge font sizes to read stuff compared to using very dim setting on my screens and light mode." I think the article

"FWIW, I've tried dark mode and have to enlarge font sizes to read stuff compared to using very dim setting on my screens and light mode." I think the article mentions this indirectly, but then attributes it. Your pupils are going to adjust to the amount of light entering them a lot (most?). This means like a camera, a smaller hole will be less sensitive to focal problems. So, unless you perfectly compensated for the amount of light coming from your display its likely the brighter backgrounds were dumping more light, reducing your pupils and making things clearer.