1. Lighting conditions for cycled light versus dimmed light or near darkness.

Reference	Intervention	Daytime light intensity	Night‐time light intensity
Seiberth 1994	Cycled light	Mean 342 lux (SD 55 lux) in the NICU Mean 415 lux (SD 42 lux) in the stepdown unit	Mean 62 lux (SD 53 lux) in the NICU Mean 38 lux (SD 18 lux) in the stepdown unit
	Near darkness	99.9% light reduction	99.9% light reduction
Boo N‐Y 2002	Cycled light	Mean 78.4 lux (SD 24.7 lux)	Mean 5.9 lux (SD 1.9 lux)
	Dimmed light	Mean 5.9 lux (SD 1.9 lux)	Mean 5.9 lux (SD 1.9 lux)
Brandon 2002	Cycled light	Range 200‐225 lux	Range 5‐10 lux
	Near darkness	Range 5‐10 lux	Range 5‐10 lux
Mirmiran 2003	Cycled light	300 lux	< 20 lux
	Dimmed light	< 20 lux	< 20 lux
Rivkees 2004	Cycled light	Mean 239 lux (SD 29 lux)	< 25 lux
	Dimmed light	Mean 28.5 lux (SD 3 lux)	< 25 lux
Guyer 2012	Cycled light	499.3 (SD 159.2) lux	28.5 (SD 27.5) lux
	Dimmed light	97.6 (SD 45.3) lux	20.8 (SD 20.7) lux

NICU: neonatal intensive care unit; SD: standard deviation