Human Circadian Sensitivity to Very Short Light Pulses

This study has been completed.
Information provided by (Responsible Party):
Elizabeth B. Klerman, Brigham and Women's Hospital Identifier:
First received: April 1, 2011
Last updated: August 19, 2011
Last verified: August 2011

The mammalian eye serves both visual and non-image-forming functions. New information about the non-image-forming anatomy and physiology of the eye has revealed effects of ocular light stimuli on human circadian rhythms, melatonin suppression, heart rate, pupillary reflexes, cognitive performance, alertness and sleep. The results of the proposed work can be used to make predictions about the effects of light, to make recommendations involving exposure to or avoidance of light, and to design environmental lighting, resulting in improved health and alertness and decreased errors and accidents.

Condition Intervention
Circadian Rhythm Disorders
Other: Ocular light or darkness exposure

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Basic Science
Official Title: Human Circadian Sensitivity to Very Short Light Pulses

Further study details as provided by Brigham and Women's Hospital:

Primary Outcome Measures:
  • Circadian Phase (hours) [ Time Frame: Before and after intervention (day 1) ] [ Designated as safety issue: No ]
    Circadian phase (hours) measured before and after intervention

Estimated Enrollment: 400
Study Start Date: December 2009
Study Completion Date: August 2011
Primary Completion Date: August 2011 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Ocular Light or Dark Exposure
Ocular Light or Dark Exposure
Other: Ocular light or darkness exposure
Ocular light or darkness exposure


Ages Eligible for Study:   18 Years to 30 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Healthy volunteers

Exclusion Criteria:

  • No medications
  • No eye disease
  • No sleep disorders
  • No psychiatric disorders
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Please refer to this study by its identifier: NCT01330992

United States, Massachusetts
Brigham and Women's Hospital
Boston, Massachusetts, United States, 02115
Sponsors and Collaborators
Brigham and Women's Hospital
  More Information

No publications provided

Responsible Party: Elizabeth B. Klerman, Associate Professor, Associate Physician, Brigham and Women's Hospital Identifier: NCT01330992     History of Changes
Other Study ID Numbers: NIH-RC2-HL101340
Study First Received: April 1, 2011
Last Updated: August 19, 2011
Health Authority: United States: Institutional Review Board

Keywords provided by Brigham and Women's Hospital:
Circadian rhythms
Ocular light exposure
Darkness Exposure

Additional relevant MeSH terms:
Chronobiology Disorders
Nervous System Diseases processed this record on October 13, 2015