If you have not already done so, please read Blog Posts 1 through 5 that describe how sleep is important and beneficial. I will post specific information for parents and children based on my book, “Healthy Sleep Habits, Happy Child.” Please do not be put off by my book’s length. This is a reference book. Read only the topic of interest to you.
A 2021 paper focused specifically on screen use during the hour or so leading up to bedtime (the pre-bedtime period) and separately, on screen use as part of the child’s bedtime routine:
“Whether screen use was observed during the pre-bedtime period or reported as part of the bedtime routine by the parents, the findings were consistent: greater screen use was associated with more parent-reported sleep problems [bedtime resistance and signaled awakenings]. Additionally, actigraphy [objective measurements of sleep] showed that children who were observed to use screens during the pre-bedtime period had later sleep timing [later bedtimes] and less consolidated sleep (Blog Post 11) compared to children who were not observed to use screens during the pre-bedtime observation. These results are consistent with the hypothesis that spending time using screens in the evening results in less time for nighttime sleep (Emphasis added).”
No screens in the hour or so before bedtime!
A 2022 paper explains why screens are especially harmful in young children. The researchers observed that young children are highly sensitive to light exposure, even for small amounts of light, during the hour before bedtime because light at this time suppresses the child’s own melatonin levels.