"Sleep troubles" refers to difficulties or problems that a person experiences when trying to sleep, such as trouble falling asleep, staying asleep, or having poor quality sleep. Full definition
Other reasons for sleep troubles included having to get up to use the bathroom at night, and worry or stress. (sciencedaily.com)
We're no experts, but those with sleep troubles should probably avoid looking at any smartphone display before bedtime, blue light or not. (brighthand.com)