Light Sleep: Screen Use and Sleep Health

Study Overview
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Brief Summary
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The Phone Sleep Study is being done to find out whether wearing blue light-blocking glasses in the evening improves subsequent sleep. This is a 21-day study and participants will be asked to wear a sleep-monitoring actiwatch, a heart tracker, and an activity monitor, as well as to provide screenshots of participants' smartphone's screen time app for three weeks. Participants will also be asked to wear a blood pressure cuff on their arm for three days during each week, for a total of nine days.

Official Title
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Evaluating the Consequences of Mistimed Light-emitting Device Use on Cardiac Activity and Sleep Health

Conditions
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Glasses

Intervention / Treatment
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* Device: Blue light-blocking glasses
* Device: Glasses with clear lenses


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Fluent English speaker and reader Capable of providing one's own informed consent Age 18 to 29 years old Healthy, sighted individuals Own an iOS smartphone (iPhone) Willingness to update smartphone to access the current version of the Screen Time or StayFree application, depending on smartphone operating system Willingness to participate in surveys, wear health monitoring devices, and provide screenshots of their smartphone's screentime application throughout the entire study Exclusion Criteria: Younger than 18 or older than 29 years Individuals who are blind or wear corrective lenses Taking prescribed medications that affect sleep Recent shift work Sleep disorder diagnosis or any cardiovascular disease

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 29 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Participants will be randomly assigned to wear either blue light-blocking glasses or glasses with clear lenses during the second week of the study. During the third week, participants will be assigned to wear the opposite pair of glasses. Sleep and wake behaviors are the primary study outcome.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Blue light-blocking glasses<br>Participants will wear blue light-blocking glasses to evaluate whether sleep behaviors improve. | Device: Blue light-blocking glasses<br>* Participants will be randomly assigned to wear either blue light-blocking glasses or glasses with clear lenses during the second week of the study. During the third week, participants will be assigned to wear the opposite pair of glasses.<br>* Other names: Swanwick Night Swannies;|
| Placebo Comparator: Glasses with clear lenses<br>Participants will wear glasses with clear lenses to serve as the control condition. | Device: Glasses with clear lenses<br>* Non-blue light-blocking glasses<br>* Other names: Swanwick glasses;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sleep onset | Midnight-centered clocktime of when participant falls asleep at night | Throughout the duration of the study ( 3 weeks) | 
| Sleep midpoint | Midnight-centered clocktime denoting the middle of the nocturnal sleep episode | Throughout the duration of the study ( 3 weeks) | 
| Total sleep time at night | Length of time spent asleep during the night, excluding time spent awake throughout the sleep episode | Throughout the duration of the study ( 3 weeks) |