Understanding how light affects sleep and body clocks based on age and sex

Impact of Sex and Age on Non-visual Light Input That Affects Sleep and Circadian Rhythms

This study is testing how different ages and sexes respond to light and how that affects sleep and body clocks in healthy people.

Quick facts

• Phase: NA
• Study type: Interventional
• Enrollment: 48 (estimated)
• Ages: 18 Years to 85 Years
• Sex: All
• Sponsor: Massachusetts General Hospital (other)
• Locations: 1 site (Boston, Massachusetts)
• Trial ID: NCT05829044 on ClinicalTrials.gov

What this trial studies

This clinical trial investigates how the pupil's response to light stimuli varies with age and sex, and how these responses relate to sleep patterns and circadian rhythms in healthy individuals. Participants aged 18 to 85 will undergo a special eye exam and complete questionnaires to determine eligibility. Those who qualify will wear a monitoring device for a week and then stay in a research facility for three days to assess their pupil response, body clock timing, and hormonal reactions to light exposure. The study aims to enhance our understanding of the physiological mechanisms underlying sleep and circadian rhythms.

Who should consider this trial

Good fit: Ideal candidates are healthy adults aged 18 to 85 who have specific sleep and wake times and can communicate effectively in English.

Not a fit: Patients with significant eye conditions or those who are color blind may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved strategies for managing sleep disorders and enhancing overall sleep quality based on individual characteristics.

How similar studies have performed: While the specific approach of this study may be novel, previous research has shown that light exposure significantly impacts circadian rhythms and sleep patterns.

Eligibility criteria

Inclusion Criteria:

* (i) 18-85 years old.
* (ii) Habitual sleep onset 10 pm- 1 am (healthy controls only);
* (iii) Habitual wake onset 5:30 am- 8:30 am (healthy controls only);
* (iv) vision correctable to 20/30;
* (v) stable medically.
* (vi) ability to speak, understand, and read English at a high school level

Exclusion Criteria:

* (i) Color blind by Ishihara Color Blindness Test;
* (ii) any history of eye trauma, surgery or abnormality (e.g., retinopathy, glaucoma, cataracts, amblyopia, macular degeneration, congenital color vision deficiencies, or any type of blindness) besides correctable vision abnormalities (e.g., with glasses); any abnormalities on clinical eye exam (e.g., neuritis, Neuromyelitis optica, treated or untreated glaucoma) such that the ophthalmologist recommends the participant not be studied; Limited cataracts (e.g., Lens Opacities Classification (LOCS) III grade \<2) will be allowed and documented during the eye exam. Eye drops that affect pupil size or contractility (e.g. mydriatics, miotics); drops to treat glaucoma (e.g., pilocarpine, brimonidine, other drops like artificial tear drops, or anti-inflammatory drops would not be exclusionary)
* (iii) current or history of neurologic or psychiatric disease including autonomic function disorder or migraines; psychiatric disorder requiring medications in a first degree relative (healthy controls only); limited-duration counseling without prescription medications will not be exclusionary; (iv) current or history of circadian rhythm sleep-wake disorder (healthy controls only);
* (v) prescription or non-prescription drugs affecting the pupil (e.g., affecting autonomic function), sleep, melatonin (e.g., lithium, alpha- and beta-adrenergic antagonists), and/or circadian rhythms (e.g., beta blockers, non-steroidal anti-inflammatory drugs, tricyclics);
* (vi) Other disorders that can affect or may be affected by intrinsically photosensitive Retinal Ganglion Cell (ipRGC) function, including diabetes mellitus, multiple sclerosis, Parkinson's disease, seasonal affective disorder;
* (vii) shift- or night-work in past three months; history of night work in preceding 3 year period
* (viii) crossing more than 2 time zones in past three months;
* (ix) presence of depression as assessed by a Beck Depression Inventory (BDI) score \>14.
* (x) pregnant or less than 6 weeks post-partum or breast-feeding

Where this trial is running

Boston, Massachusetts

• Massachusetts General Hospital — Boston, Massachusetts, United States (RECRUITING)

Study contacts

• Principal investigator: Elizabeth B Klerman, MD PhD — Massachusetts General Hospital
• Study coordinator: Elizabeth B Klerman, MD PhD

Conditions: Normal Physiology, eye pupil response, circadian rhythms, light, melatonin