If you feel like your eye fatigue has worsened since starting to use your current display, this could be the cause. If you're in an office, switching out displays with another member of the staff is another effective way to identify the cause.
As an aside, if you absolutely must read e-books before bedtime, you could switch to an electronic paper reader that does not emit this type of light instead of using a smartphone or tablet. You could also use the aforementioned blue light blocking glasses or blue light reducing film. 153554b96e