Seeing the World Through Assorted Glasses

Participants will complete a self-report battery containing measures of sleep quality, morningness-eveningness chronotype, and mood. Participants will then wear a wrist-worn accelerometer for 14 days to objectively record activity level and sleep quality. Participants will also fill out a daily sleep log and short self-report measures assessing sleep and mood. On days 4-7 and 11-14 of the study the participants will wear either amber or placebo control lenses prior to sleep onset in a randomized crossover design (i.e., participants will be randomized to wear either amber lenses or placebo lenses for the first part of the protocol and then switch to wear the opposite lenses for the second part of the protocol). Participants will spend nights 7 and 14 of the study in a sleep laboratory in order to obtain hourly melatonin samples and wear a wrist sleep monitor to non-invasively and objectively measure sleep state and quality using peripheral arterial tone and oxygen perfusion.

Inclusion criteria

• Good physical health
• Proficiency in written and spoken English
• Reported average total sleep time <9 hours (so nights spent in sleep lab will not result in sleep deprivation)

Exclusion criteria

• Taking regular medication affecting sleep and/or mood
• Travel across more than two time zones within the past month
• Smoke > 5 cigarettes per day
• Excessive caffeine use (>2 cups at one time or >500 mg daily)
• No current Axis I Diagnostic and Statistical Manual of Mental Disorders (DSM-5) Disorder
• No current use of street drugs
• No history of sleep disorder/bipolar disorder/psychosis/seizure disorder/chronic medical condition
• Night shift work within the past 2 months