The evidence is convergent. Multiple independent sources reach the same conclusion, the underlying mechanism is well-characterized, and even the field's most cautious voices treat it as worth doing.
I've talked before about how viewing bright lights between the hours of 10:00 p.m and 4:00 a.m has been shown in studies by Dr. Samer Hattar, David Bersin, excellent circadian scientists to reduce levels of dopamine for several days after that light exposure.
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One from the work of Hattar and colleagues showing that UVB exposure via the perihabenula can diminish the output of dopamine and other molecules that make us feel good if that UVB exposure is in the middle of the night or late evening.
The other way to ensure that dopamine levels stay high or put differently, that you don't quash whatever dopamine you have in your system is to really avoid bright light exposure to your eyes between the hours of 10:00 PM and 4:00 AM or another way of putting this because I realize people sleep at different times, et cetera, is to avoid bright light exposure to your eyes, not just blue light, but all colors of light in phase three, that is 17 to 24 hours after waking up because that's really when you should be asleep or trying to get asleep, if you're having trouble sleeping.
It's also going to negatively impact dopamine levels, not just that night, but the subsequent day.
I don't want to get into too many details right now, but really try and keep the lights dim in the middle of the night or off, if you can do that safely. It's really going to help if you're turning on your phone brightly, if you are turning on bright lights, it's not just going to negatively impact melatonin, the hormone that helps you fall and stay asleep. It's also going to negatively impact dopamine levels, not just that night, but the subsequent day.
Light that arrives to the eyes between 11:00 PM and 4:00 AM approximately, suppresses the release of dopamine. This neuromodulator that makes us feel good is sort of an endogenous antidepressant and can inhibit learning and create all sorts of other detrimental effects.
10 minutes of bright outdoor light within the first hour of waking anchors the circadian phase and improves sleep onset that night.
Morning sunlight exposure shifts the cortisol awakening response forward, improving daytime alertness.
Long-term morning sunlight reduces age-related macular degeneration risk.
Sleep regularity predicts all-cause mortality more strongly than sleep duration.
Tracking deep sleep on a wearable accurately reflects EEG-measured slow-wave sleep.
Caffeine has a half-life long enough that consumption after 2pm measurably degrades deep sleep in slow metabolizers.