“Screens and blue light before bed ruin your sleep.”
Moderate confidence. Evening light and screen use can affect sleep, but trials of blue-light-filtering lenses are small and inconsistent. Screen timing, brightness, duration and what a person does on the device also vary, so blue light alone should not be treated as the whole explanation.
Bright, engaging screen use near bedtime can delay or disrupt sleep, but blue light is only one possible pathway. Blue-light-filtering glasses have not shown a consistent sleep benefit in randomized trials.
A screen can affect sleep by exposing the eyes to light, keeping the brain engaged and simply extending wake time. A dim, brief task is not equivalent to hours of bright, emotionally engaging use.
Safety note: Persistent insomnia or daytime sleepiness should not be attributed to screens without considering medications, mood, substance use, schedule and sleep disorders.
Talk to a healthcare professional if: Seek help for insomnia lasting months, dangerous daytime sleepiness, drowsy driving, or symptoms such as loud snoring and witnessed breathing pauses.
If screens are crowding out sleep or keeping you alert, changing the habit is more dependable than relying on a filter or special glasses.
For one to two weeks, reduce bright or absorbing screen use during your wind-down and keep the phone from extending bedtime. Judge the change by sleep timing and daytime function.
Similar claims on Blue light & screens before bed
Don't stress about blue light so much as what the screen does to your bedtime and your brain. A boring wind-down beats a blue-light filter.