An interventional study of Circadian OS iPad-based light app in Circadian Rhythms, sponsored by Circadian OS, Inc. Enrolling by invitation at 1 site in United States. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-08-04.
Sponsored by Circadian OS, Inc · Not applicable, Interventional, and Other
This study looks at how adults use an iPad-based light app in everyday life.
Light is the main signal that sets the body's internal clock, which controls daily rhythms in sleep, alertness, and many other body systems. Indoor living means many people do not get bright light at a consistent time each day.
The app uses the iPad screen to deliver light while people watch videos, read, or browse. It suggests about one hour of use per day, started within about two hours of waking. It does not require anyone to follow that schedule, and no one is locked out for using it more, less, or at other times. The app shows people when they are positioned to receive the intended light, records how the app is used, and asks short questions about sleep.
The main questions this study aims to answer are:
Participants will use the app on an iPad for up to eight weeks, answer short questions about their sleep and how they feel, and share feedback about their experience.
Participants may also choose to take part in optional sub-studies. They can wear a device the sponsor provides to record movement, light exposure, and skin temperature, or share data from a wearable device they already use. They can also give blood, saliva, or urine samples, which researchers will use to describe daily patterns in clock-related genes and other markers. These sub-studies are entirely exploratory and voluntary, and participants can take part in the main study without them.
Participants will not receive results from any samples they give. This study does not provide medical treatment, and it is not designed to determine whether the app treats or improves any medical condition.
This is a single-site, longitudinal study evaluating how adults use KairOS, an iPad-based light application developed by Circadian OS, Inc., in everyday life for up to eight weeks. Participants are encouraged to use the app for approximately 60 minutes daily within two hours of waking, but use is not enforced. Zero-use stretches, partial weeks, and re-engagement after a gap are recorded as participation data rather than protocol deviations. App telemetry, sleep logs, and participant feedback are used to characterize patterns of use and overall usability. Participants may also opt into an exploratory biomarker sub-study involving collection of blood, saliva, or urine samples; no laboratory results are returned to participants. Other optional activities include actigraphy, light-exposure monitoring, and moderated task-observation sessions.
This is the only study on the registry with Circadian OS, Inc as lead sponsor.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Participants receive the investigational Circadian OS iPad-based light app and use it in their normal environment over a defined exposure period. App onboarding presents a recommended use envelope of approximately 60 minutes per day within approximately 2 hours of habitual wake time, anchored to the participant's Munich ChronoType Questionnaire response. Use is not enforced: the app does not lock out participants who use it less, more, or outside the recommended window, and non-use is recorded as participation data. Participants complete brief in-app check-ins on sleep and experience, plus periodic usability surveys. Optional sub-studies (actigraphy, biomarker collection, moderated human-factors observation) are independently elected by participants within this single arm.
Device: Circadian OS iPad-based light app
Software-based light-delivery platform running on an off-the-shelf iPad. The app uses the display to deliver light targeting a specified circadian stimulus (CS ≥ 0.3), integrating spectrum and intensity at the eye. It runs closed-loop: screen luminance is calibrated in advance, the iPad camera tracks viewing distance and gaze direction, and the app computes the dose reaching the eye in real time, signaling whether the user is positioned to receive it. Session start-time recommendations are anchored to each participant's habitual wake time, derived from the Munich ChronoType Questionnaire. Onboarding presents a recommended envelope of approximately 60 minutes per day within approximately 2 hours of habitual wake. Use is not enforced and the app does not lock out off-envelope use. Participants use the app while streaming, reading, or browsing as they normally would.
Also known as: KairOS, Circadian OS app
Frequency of Circadian OS app (KairOS) use
Number of light-delivery sessions completed per participant per week, captured by in-app telemetry.
Time frame: From initiation of app use through the end of the app-exposure period, up to eight weeks
Duration of app use: minutes of light exposure per session
Duration in minutes of each light-delivery session, captured by in-app telemetry.
Time frame: From initiation of app use through the end of the app-exposure period, up to eight weeks
Timing of app use relative to habitual wake time
Start time of each light-delivery session, expressed as hours elapsed since the participant's habitual wake time, as measured by the Munich Chronotype Questionnaire completed at baseline.
Time frame: From initiation of app use through the end of the app-exposure period, up to eight weeks
Context of app use
Concurrent on-screen activity during light-delivery sessions, captured by in-app telemetry.
Time frame: From initiation of app use through the end of the app-exposure period, up to eight weeks
Participant-reported feedback on the app experience, usability, and perceived effects
Structured and free-text participant feedback on the app experience, usability, and perceived effects, including the Perceived Effects Scale (Compared to Before the Study), a study-specific 5-point Likert measure (range 1-5, higher scores indicate a better perceived outcome; 1 = Much worse, 2 = Somewhat worse, 3 = No change, 4 = Somewhat better, 5 = Much better).
Time frame: Weekly during the app-exposure period and at the end of the app-exposure period, up to eight weeks
Self-reported sleep and circadian-rhythm parameters during the exposure period
Participant-reported sleep parameters captured through an in-app daily sleep log during the exposure period, including bedtime, wake time, nighttime awakenings, napping, and sleep quality. Weekly participant check-ins capture sleep quality and daytime alertness relative to usual.
Time frame: From initiation of app use through the end of the app-exposure period, up to eight weeks
Drop-off and return-to-use patterns
Consecutive zero-use days per participant, partial weeks of use, and re-engagement events following a use gap.
Time frame: From initiation of app use through the end of the app-exposure period, up to eight weeks
System Usability Scale (SUS) score
Participant-completed 10-item System Usability Scale, scored 0-100, with higher scores indicating better perceived usability.
Time frame: End of Week 1 and end of the app-exposure period; a single administration is done at the end of Week 1 when the app-exposure period is one week
Number of Use Errors Identified During App Use
Use errors identified from in-app telemetry and participant-reported problems, documented with description and frequency.
Time frame: From initiation of app use through the end of the app-exposure period, up to eight weeks
Root-Cause Category of Identified Use Errors
Identified use errors are categorized by root cause (perception, cognition, or action) per human-factors methodology, based on in-app telemetry and participant-reported problems.
Time frame: From initiation of app use through the end of the app-exposure period, up to eight weeks
Plan to share: No — Individual participant data will not be shared outside the Sponsor. Per the study protocol, no coded or identified data are shared outside the Sponsor, and no biospecimens are shipped to any external laboratory. The Sponsor will return to the IRB before any external sharing is contemplated. Participant consent does not authorize sharing of individual participant data outside the study team.
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