Research by the Lighting Research Center on Apple "Night Shift" mode has shown that it may be of little help to late night device users.
Apple's Night Shift turns the screen warmer colours, and claims to eliminate some of the melatonin suppressing blue light.
The researchers concluded that just changing the colours of the screen may be ineffective. The researchers suggest also dimming the brightness level of the screen for best results.
The full report can be found here: http://journals.sagepub.com/doi/abs/10.1177/1477153517748189