The current Eye Comfort Shield works great during the day, but at night it doesn't block enough blue light, for example, while reading in bed in a dark room, thus impacting melatonin production. The Red Color Filter setting in Accesibility would work great for this, however, it just displays a color overlay on the UI, meaning, a lot of contrast is lost. Several root solutions for this exist, however, I don't think a typical user should root their phone just for this. Ideally, both green and blue channels should turn to 0, leaving only red at 255.
iOS's Color Tint setting takes the same concept, but improves on it by displaying only the selected color instead of drawing an overaly.
