I think we need about 10000 lux, i could be wrong, but just some old numbers I recall, I'm not sure if mobile screens can produce that much - comparing my phone to my monitor, there's no chance right now my phone competes with the brightness of my monitor. It most certainly can't compete with my OLED tv, none of my screens can.
it's hard to say... like I said it's fine to be on either position, since nothing is certain yet, but I just paid for eye surgery, my eyes are an investment for as long as I can keep em in that condition.