It is my belief that too high colour temperature causes eye strain when you look at any kind of display for long periods of time. Colour temperature can basically be simplified to "how white a white colour is". If you for example take any real world item that you think is white (piece of paper, Apple charger, a wall...) and compare it to white on any display (for example google.com's background is pure white) you have around, you will likely notice that the white on the display is much more whiter than any white object you can find. This difference in ambient colour temperature and the colour temperature on your display makes it somewhat uncomfortable to look at the display and causes eye strain, especially if you read text on white background a lot through out the day. Now in iOS 10 there is a way to lower the colour temperature using the new Colour Filters feature. It's a bit "hacky" and I hope Apple would provide a better way to do it, but for now this will have to do. 1. Make sure Night Shift is turned off 2. Turn on Colour Filters in Settings -> General -> Accessibility -> Display Accommodations -> Colour Filters 3. Select the fourth option: Colour Tint 4. Slide the Intensity slider to maximum 5. Find yellow colour using the Hue slider. You can tint it slightly to orange if you like, but I recommend yellow / mostly yellow. 6. Adjust the Intensity slider to your preference. I have it at about a third way from left. You can continue using Night Shift as normal. It will lower the colour temperature even more when the sun sets, which is good because the ambient colour temperature will likely be even lower at that time.