The link between blue light and sleep is murkier than we thought, said Lauren E. Hartstein, an assistant professor of psychiatry at the University of Arizona. She and other researchers have been taking a closer look at the evidence, which suggests that blue light alone may not be causing poor sleep. And in some cases, screen use could even help you drift off. Here’s what studies on blue light actually suggest — and what may help you sleep more soundly. nytimes.com/2025/08/17/we..