Blocking blue light at night stops melatonin loss without affecting performance during simulated night shifts

Salivary melatonin levels were preserved in bright light when using goggles that filtered wavelengths below 530 nm.

• Bright light conditions suppressed melatonin production in unfiltered light.
• Goggles filtering wavelengths less than 530 nm maintained melatonin levels comparable to those in dim light.
• No negative effects on performance, subjective sleepiness, or alertness were observed while wearing the goggles.
• The study included 19 healthy young adults (11 males and 8 females) with a mean age of 24.7 years.
• Measurements were taken during three nonconsecutive nights over a two-week period.

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