Comment by Eisenstein

I find meta-analysis are better for understanding the current state of research on a particular topic.

"A systematic search of PubMed, Scopus, and Web of Science identified randomized controlled trials (RCTs) from 2010 to 2024. Eligible studies enrolled adults using BBGs before bedtime and reported actigraphy-derived outcomes. Random-effects meta-analysis was performed using the generic inverse variance method. The review was registered in PROSPERO (CRD420251034611).

Results

Three double-blind crossover RCTs (n = 49) were included. BBGs showed a non-significant reduction in SOL (MD = −4.86 min; 95% CI: −20.23 to 10.52; p = 0.54) and a non-significant increase in TST (MD = 8.75 min; 95% CI: −35.31 to 52.82; p = 0.70). No significant effects were found for SE (MD = −0.61; 95% CI: −7.58 to 6.35; p = 0.86) or WASO (MD = −1.47; 95% CI: −14.94 to 11.99; p = 0.83). Heterogeneity was low (I2 = 0%).

Conclusion

BBGs may provide small improvements in sleep, but current evidence from RCTs does not support significant effects. Larger, well-powered trials with standardized protocols are needed."

- Efficacy of blue-light blocking glasses on actigraphic sleep outcomes: a systematic review and meta-analysis of randomized controlled crossover trials - https://doi.org/10.3389/fneur.2025.1699303