. 2022 Aug 16;13:943108. doi: 10.3389/fphys.2022.943108

TABLE 3.

Effects of blue light on sleep.

Study	Age (years) participants (n)	Activity	Intervention/Exposure	Duration of intervention	Measurement tool	Methodological characteristics	Outcome
Ayaki et al. (2016)	29 ± 5	Tasks on portable device before bedtime	iPad without BLB glasses vs. iPad with BLB glasses	2 h	Actigraphy to monitor sleep, modified KSS and PSQI	Controlled study	Sleep efficacy significant ↑ with BLB glasses
	n = 12						Sleep latency significant ↓ with BLB glasses
	n = 12						Sleepiness no significant ↓ in BL
Bowler and Bourke (2019)	20.5	Facebook before bedtime	iPad without BL filter vs. iPad with amber filter	22.5 min	Modified PSQI	RCT	Sleep quality no significant change in BL
Bowler and Bourke (2019)	n = 30	Facebook before bedtime	iPad without BL filter vs. iPad with amber filter	22.5 min	Modified PSQI	RCT	Sleep quality no significant change in BL
Burkhart and Phelps (2009)	34 ± 8.2	Bedtime routine	Yellow tinted safety glasses vs. BLB amber glasses	3 h	Sleep diary with Likert scale	RCT	Sleep quality significant ↑ with BLB glasses in the last week
Burkhart and Phelps (2009)	n = 20	Bedtime routine	Yellow tinted safety glasses vs. BLB amber glasses	3 h	Sleep diary with Likert scale	RCT
Cajochen et al. (2011)	23.8 ± 5.0	Watching a relaxing movie and reading tasks	BL computer screen, (6.953 K LED, 440–470 nm) vs. CCFL (4.775 K)	5 h	KDT, KSS	Controlled crossover study	Subjective sleepiness significant ↓ in BL
Cajochen et al. (2011)	n = 13	Watching a relaxing movie and reading tasks		5 h	KDT, KSS	Controlled crossover study	Subjective sleepiness significant ↓ in BL
Chang et al. (2015);	24.9 ± 2.9	Reading before bedtime	Tablet (452 nm) vs. hard copy book	4 h	EEG, KSS, PSG	RCT, crossover study	Evening sleepiness significant ↓ in BL
	24.9 ± 2.9						Morning alertness significantly delayed in BL
	n = 12						Sleep efficiency, total sleep time no significant change in BL
	n = 12						Sleep latency significant ↑ in BL
Chellappa et al. (2013)	25.2 ± 3.1	Sitting in the evening	BL (6.5 K) vs. WL (3 K)	2 h	All night EEG	Controlled crossover study	Wakefulness no significant ↓ in BL
Chellappa et al. (2013)	n = 30	Sitting in the evening	BL (6.5 K) vs. WL (3 K)	2 h	All night EEG	Controlled crossover study	Wakefulness no significant ↓ in BL
Chindamo et al. (2019)	17.5 months	Tasks on portable device during daytime routine	Tablets or smartphones vs. hard copy book	Everyday use	Questionnaire	Cross-sectional study	Sleep onset latency significant ↑ in BL
Chindamo et al. (2019)	n = 1,117	Tasks on portable device during daytime routine	Tablets or smartphones vs. hard copy book	Everyday use	Questionnaire	Cross-sectional study	Total sleep time significant ↓ in BL
Driller and Uiga (2019)	28 ± 5.0	Reading before bedtime	iPad vs. hard copy book	1 h	Actigraphy, Likert scale	RCT, crossover study	Sleep duration and sleep efficiency no significant negative change in BL
Driller and Uiga (2019)	n = 14	Reading before bedtime	iPad vs. hard copy book	1 h	Actigraphy, Likert scale	RCT, crossover study	Sleep quality no significant ↓ in BL
Gabel et al. (2013)	23.1 ± 0.8	Cognitive tasks during morning hours	BL (470 nm) vs. DSL	20 min	KSS	Controlled study	Subjective sleepiness significant ↑ in BL after second night
Gabel et al. (2013)	n = 17	Cognitive tasks during morning hours	BL (470 nm) vs. DSL	20 min	KSS	Controlled study
Grønli et al. (2016)	25.1 ± 2.9	Reading before bedtime	iPad vs. hard copy book	30 min	KSS, Online questionnaire, PSG, sleep diary	RCT, crossover study	Sleep duration, sleep onset latency no significant change in BL
Grønli et al. (2016)	n = 16	Reading before bedtime	iPad vs. hard copy book	30 min	KSS, Online questionnaire, PSG, sleep diary	RCT, crossover study	Subjective sleepiness significant ↓ in BL
Heath et al. (2014)	17.4 ± 1.9	Playing games before bedtime	iPad vs. iPad with shortwavelength filter	48 min	PSG for sleep onset latency, SSS	Counterbalanced controlled study	Sleep onset latency and subjective sleepiness no significant change in BL
Heath et al. (2014)	n = 16	Playing games before bedtime	iPad vs. iPad with shortwavelength filter	48 min	PSG for sleep onset latency, SSS	Counterbalanced controlled study
Heo et al. (2017)	31.0 ± 4.2	Smartphone use during the morning	Smartphone vs. Smartphone display filter	150 min	ESS, FSS, PSQI	RCT, crossover study	Sleepiness significant ↓ in BL
Heo et al. (2017)	n = 22	Smartphone use during the morning	Smartphone vs. Smartphone display filter	150 min	ESS, FSS, PSQI	RCT, crossover study	Sleepiness significant ↓ in BL
Iskra-Golec et al. (2012)	28.3 ± 2.8	Sitting, office work during the day	BL (17 K, 420 nm–480 nm vs. WL (4 K)	3 weeks, office hours	KSS during week	Field experiment counterbalanced	Sleepiness significant ↑ in BL
Iskra-Golec et al. (2012)	n = 30	Sitting, office work during the day	BL (17 K, 420 nm–480 nm vs. WL (4 K)	3 weeks, office hours	KSS during week	Field experiment counterbalanced	Sleepiness significant ↑ in BL
Knufinke et al. (2018)	18.8 ± 3.0	Elite athletes training	BL emitting activities within the last hour before bedtime	1 h	CSD, HSDQ, KSS, online survey, diaries, PSQI, SHI	Qualitative study	Sleep onset latency no significant ↓ in BL
Knufinke et al. (2018)	n = 98	Elite athletes training	BL emitting activities within the last hour before bedtime	1 h	CSD, HSDQ, KSS, online survey, diaries, PSQI, SHI	Qualitative study	Sleep onset latency no significant ↓ in BL
Lockley et al. (2006)	23.3 ± 2.4	Sitting still	BL (460 nm) vs. 555 nm-light	6.5 h	KSD, KSS during BL	RCT	Subjective sleepiness significant ↓ during BL, but not at onset of BL exposure
Lockley et al. (2006)	n = 16	Sitting still	BL (460 nm) vs. 555 nm-light	6.5 h	KSD, KSS during BL	RCT
Motamedzadeh et al. (2017)	30.2 ± 4.1	Sitting during night shift	BL (17 K) vs. BL (6.5 K) vs. WL	1 week	KSS	RCT	Sleepiness significant ↓ in BL
Motamedzadeh et al. (2017)	n = 30	Sitting during night shift	BL (17 K) vs. BL (6.5 K) vs. WL	1 week	KSS	RCT	Sleepiness significant ↓ in BL
Münch et al. (2016)	23.2 ± 3.3	Bedtime routine	BL (750 lux, 3,537 K) vs. OL (100 lux, 1,500 K) vs. CTRL (40 lux, 2,600 K)	30 min	EEG, VAS	RCT, Crossover study	Subjective sleepiness significant ↓ in BL compared to CTRL
Münch et al. (2016)	n = 18	Bedtime routine		30 min	EEG, VAS	RCT, Crossover study	Total sleep time significant ↓ in BL compared to OL
Phipps-Nelson et al. (2009)	32.1 ± 6.8	Driving during the night	BL (430 nm) vs. RL (620 nm)	6 h	KSS	RCT	Subjective sleepiness no significant change in BL
Phipps-Nelson et al. (2009)	n = 8	Driving during the night	BL (430 nm) vs. RL (620 nm)	6 h	KSS	RCT	Subjective sleepiness no significant change in BL
Rångtell et al. (2016)	Adults	Reading a book	LED tablet (ASUS Transformer Pad TF700) vs. hard copy	2 h	KSS, PSG	RCT	Sleep duration, sleep onset latency, subjective arousal and subjective sleepiness no significant change in BL
Rångtell et al. (2016)	n = 14	Reading a book	LED tablet (ASUS Transformer Pad TF700) vs. hard copy	2 h	KSS, PSG	RCT
Sahin and Figueiro (2013)	20.8	Sitting, post lunch dip	BL (470 nm) vs. RL (630 nm)	48 min	KSS	RCT	Subjective sleepiness no significant change in BL
Sahin and Figueiro (2013)	n = 13	Sitting, post lunch dip	BL (470 nm) vs. RL (630 nm)	48 min	KSS	RCT	Subjective sleepiness no significant change in BL
Sander et al. (2015)	65	Spending time at home	BL (5100 K, 450 nm) vs. Blue-suppressed light (2800 K, 625 nm)	3 weeks	PSQI, questionnaire	RCT, crossover study	Sleep duration, sleep quality no significant change in BL
Sander et al. (2015)	n = 38	Spending time at home		3 weeks	PSQI, questionnaire	RCT, crossover study	Sleep duration, sleep quality no significant change in BL
Van Der Lely et al. (2015)	16	Sitting in the evening	CL glasses vs. BLB glasses	3 h	EEG, KSS	Balanced crossover study	Subjective sleepiness significant ↑ with BLB glasses
Van Der Lely et al. (2015)	n = 13	Sitting in the evening	CL glasses vs. BLB glasses	3 h	EEG, KSS	Balanced crossover study	Subjective sleepiness significant ↑ with BLB glasses
Viola et al. (2008)	36.4 ± 10.2	Office work during the day	BL (420–480 nm) vs. WL	4 weeks	KSS, PSQI	Controlled crossover study	Daytime sleepiness significant ↓ in BL
	36.4 ± 10.2						Evening fatigue significant ↓ in BL
	n = 94						Sleep duration significant ↑ in BL
	n = 94						Sleep quality significant ↑ in BL
Yang et al. (2018)	20 ± 3.4	Nightshift work	Intermittent BL (6000 K) vs. continuous bright light vs. continuous dim light (3600 K)	30 min	KSS, PSG	RCT	Sleep efficiency significant ↓ in BL and in continuous bright light
Yang et al. (2018)	n = 15	Nightshift work		30 min	KSS, PSG	RCT	Sleep onset latency no significant change in BL Total sleep time significant ↓ in BL and in continuous bright light

Increase (↑), decrease (↓), blue light (BL), blue light blocking (BLB), cold cathode fluorescent lamp (CCFL), clear lenses (CL), Consensus Sleep Diary (CSD), dawn simulation light (DSL), electroencephalography (EEG), Epworth Sleepiness Scale (ESS), Fatigue Severity Scale (FSS), Holland Sleep Disorder Questionnaire (HSDQ), thousand (K), Karolinska Drowsiness Test (KDT), Karolinska Sleep Diary (KSD), Karolinska Sleepiness Scale (KSS), light emitting diode (LED), orange light (OL), polysomnography (PSG), Pittsburgh Sleep Quality Index (PSQI), randomized controlled trial (RCT), red light (RL), Sleep Hygiene Index (SHI), Stanford Sleepiness Scale (SSS), Visual Analogue Scale (VAS) and white light (WL).