I recommend a computer add-on called F.lux to spare your eyes & improve your onscreen life, for MAC, Linux, and Windows. It calibrates monitor brightness to your location and time of day. I’ve been using it for several months and really like the mellowing effect, especially when I work evening hours. You can read about it and download it at this link. Oh, and it’s free. Props to @herf and @lorna for making this useful program.