There’s no evidence that blue blocking reduces eye strain. In short that has more to do with taking breaks, text size, and your glasses Rx.

Blue light is incredibly important and in fact should be consumed/absorbed from wake until ~60 but ideally 90 minutes before you want to be asleep. In fact, blocking blue light during the day is detrimental to your natural rhythms and has cascading effects.

Blocking at night will allow your natural melatonin expression. I use the Rise Science app to predict my circadian and get a reminder to put on blue blockers as my melatonin window approaches (time shifts daily).

For more info look up Dr. Satchin Panda (book) and several Dr. Andrew Huberman podcast episodes.