Optimizing the Potential Utility of Blue‑Blocking Glasses for Sleep and Circadian Health
Summary
This review examined the effectiveness of blue-blocking glasses as a tool for supporting circadian rhythms and sleep. The authors introduced a standardized metric (melanopic daylight filtering density, or mDFD) to rate how well different lenses reduce the type of light that delays melatonin release. Out of 26 commercially available products tested, only those with stronger filtering (mDFD ≥1) meaningfully reduced this light input. Evidence from intervention studies showed that when used correctly—such as after a night shift on the commute home or before trying to sleep during the day—blue-blocking glasses improved at least one circadian or sleep-related outcome. Effectiveness depended not only on filtering strength but also on timing and consistency of use.
Why It Matters For Night Shift Workers and Night Owls
For night-shift workers, bright light at the wrong time—especially during the commute home—can signal the brain to stay awake and make daytime sleep harder. This study shows that blue-blocking glasses are a practical, low-cost option, but only when chosen carefully and worn at the right times. Using weak lenses or putting them on too early may reduce effectiveness, while consistent, targeted use can help preserve melatonin signals, making it easier to rest and align circadian health despite a night schedule.
Notes
Open access.