Table 3.

Phototherapy for insomnia and disturbed circadian rhythm.

Therapy	Evaluation item	Evaluation results
Bright light therapy	Representative Study Design	Literature	Population	N	RCT	Placebo effect excluded	Objective biomarkers	Follow-up
		(112)	(c) poststroke insomnia patients	56	Yes	Yes	Yes	No
		(113)	(a) diagnosed by DSM-5	14	Yes	No	Yes	No
		(114)	(c) post-acute coronary syndrome patients	15	Yes	No	No	No
	Main Clinical Findings & Safety	Improves subjective sleep quality and insomnia. Modestly increases total sleep time, reduces night awakenings, and slightly boosts sleep efficiency (109, 111, 120). Effects on sleep latency are mixed. Generally safe; side effects are mild and transient (headache, eye strain, glare).
	Limitations	Small/short trials; inconsistent light parameters (timing/dose/spectrum); limited sham controls and long-term data; mixed objective outcomes.
	Evidence Level	Emerging. Small controlled studies suggest short-term subjective benefits, but evidence is limited by small samples, indirect populations, limited sham controls, and inconsistent objective outcomes.
Infrared LED light	Representative Study Design	Literature	Population	N	RCT	Placebo effect excluded	Objective biomarkers	Follow-up
		(115)	(b) adults with subclinical sleep complaints	30	Yes	Yes	Yes	No
		(116)	(d) shift-working nurses	64	Yes	No	No	No
		(117)	(b) older adults	59	Yes	No	Yes	No
		(119)	(e) healthy men	24	Yes	Yes	Yes	No
	Main Clinical Findings & Safety	Small indirect/subclinical RCTs suggest subjective benefits, but objective and insomnia-specific efficacy remains uncertain. Short-term use appears well tolerated.
	Limitations	Limited by small samples, no long-term follow-up, and most lacking placebo controls. All evaluated indirect populations rather than diagnosed clinical insomnia.
	Evidence Level	Exploratory. Multiple RCTs suggest subjective benefits and good safety, but the evidence is downgraded due to indirect populations, small sample sizes, absent follow-up, inconsistent objective outcomes, and high risk of bias from inadequate placebo controls.
40Hz flickering light	Representative Study Design	Literature	Population	N	RCT	Placebo effect excluded	Objective biomarkers	Follow-up
		(107)	(e) sleep-deprived rats	32	No	No	Yes	No
		(108)	(b) children (e) healthy adults (e) mice	49 children, 16 adults, mice	No	No	Yes	No
	Main Clinical Findings & Safety	40Hz light promotes sleep in children with insomnia and alertness in sleep-deprived rats, with no adverse ocular or systemic effects.
	Limitations	Relies on preclinical models and one uncontrolled pediatric pilot study. Lacks sham-controlled RCTs, long-term follow-up, and direct validation in adult insomnia disorder.
	Evidence Level	Exploratory. Based only on preclinical data and one uncontrolled pediatric pilot study; lacks adult RCTs and long-term validation.