Peter The original XBox One, although there is a little variance from unit to unit, ranges from "some eyestrain" to "just fine" for me, depending on the app/game. This is in stark contrast to the XBox 360, which never once gave me eyestrain, even after prolonged use. It still doesn't. I'm hoping that the XBox One X has similar base output, I don't own any 4k devices so I'm not worried about the 4k UHD playback. Although I'm keen to know if the unpleasantness degen experienced was on a 1080p display or a 4k display.