Especially for sleeping issues, but also for eye strain, I recommend using a program like flux (for a computer) that allows you to set the color temperature for the day and the gradually lower it further at evening and night. This along with dimming or using different lower temperature lightbulbs in the evening/night (not being exposed to bright/florescent lights) really helped me with falling asleep.

edit: also, lowering the brightness on the monitor itself (mine is set to 27) and in the graphics card control panel (39 for me), and then manually lowering it further in the evening/night in the control panel (25>15>9>0 is how I do it)