The Head Injury-associated Photosensitivity and Pupillary Function (HIPP) Study (HIPP)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01942564
Recruitment Status : Completed
First Posted : September 16, 2013
Last Update Posted : September 25, 2017
U.S. Army Medical Research and Materiel Command
Information provided by (Responsible Party):
Andrew Hartwick, Ohio State University

Brief Summary:
After a head injury, many people find that exposure to light causes them increased discomfort. By measuring how the pupil in the eye constricts to flashes of red and blue light, this study will investigate whether this phenomenon is due to a change in the eye's sensitivity to light.

Condition or disease
Head Injury Traumatic Brain Injury (TBI) Photosensitivity Photophobia

Detailed Description:

The pupils inside the eyes constrict in response to light stimulation. Different classes of cells within the human retina initiate this response. Recent research suggests that one of the ganglion cell types involved in this pupil response also plays a role in the photophobia experienced by migraine sufferers. The main aim of this study is to determine whether this type of ganglion cell becomes 'hypersensitive' after traumatic brain injury, thereby contributing to symptoms of increased photosensitivity experienced by many of these individuals.

In the first session of this study, subjects will be asked questions about their sensitivity to light and the reaction of their eyes' pupils to flashing red and blue lights will be measured. The subjects will be given a full eye examination to rule out other causes of increased photosensitivity.

In some cases, subjects will be asked to attend a second session roughly two weeks later. They will be asked to wear a watch that measures their daily activity/sleep rhythms and light exposure during this inter-session period. During the second session, further testing of the pupil responses to blue and red flickering light will be performed.

Study Type : Observational
Actual Enrollment : 40 participants
Observational Model: Case-Control
Time Perspective: Cross-Sectional
Official Title: The Head Injury-associated Photosensitivity and Pupillary Function (HIPP) Study
Study Start Date : August 2013
Actual Primary Completion Date : December 2014
Actual Study Completion Date : December 2015

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Head Injuries

Case Subjects
  1. Age 18 years or older
  2. Had a head injury that occurred at least 6 months prior to entering study
  3. Have found lights more bothersome since injury
Control Subjects
  1. Age 18 years or older
  2. Have not had a previous head injury
  3. Have had a full eye examination at Ohio State University College of Optometry during last 6 months.

Primary Outcome Measures :
  1. Pupil Responses [ Time Frame: 2 weeks ]
    The pupil fluctuation evoked by blue and red flickering lights will be measured in patients with a prior brain injury and compared to matched controls.

Secondary Outcome Measures :
  1. Sleep Rhythms [ Time Frame: 2 weeks ]
    Daily rhythms of sleep and activity will be assessed in subjects with prior brain injury and compared to matched controls.

  2. Light Exposure [ Time Frame: 2 weeks ]
    The exposure to red, blue and green components of the light spectrum will be quantified in patients with a prior brain injury, and compared to matched controls.

  3. Photosensitivity Symptoms [ Time Frame: Single visit - one day ]
    Subjects will complete survey indicating symptoms they have experienced related to light sensitivity and will grade their discomfort after exposed to brief flashes of light.

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population

Cases: Age 18 or older with symptoms of increased photosensitivity since experiencing a head injury.

Controls: Matched to cases in age, sex and race.


Inclusion Criteria:

  • 18+ years old
  • reports a previous head injury that occurred at least 6 months ago
  • score of 2 or 3 (mild TBI) on OSU-TBI ID Survey
  • best-corrected visual acuity of at least 20/30 in both eyes
  • reliable visual field

Exclusion Criteria:

  • pregnancy
  • significant afferent pupillary defect
  • previous history of neurodegenerative disease
  • intraocular pressure more than 21 mm Hg
  • significant visual field defect
  • active corneal pathology
  • history of retinal or optic nerve disease
  • strabismus (eye turn)

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01942564

United States, Ohio
College of Optometry
Columbus, Ohio, United States, 43210
Sponsors and Collaborators
Ohio State University
U.S. Army Medical Research and Materiel Command
Principal Investigator: Andrew Hartwick, OD, PhD Ohio State University

Additional Information:
Publications of Results:
Other Publications:
Responsible Party: Andrew Hartwick, Assistant Professor, Ohio State University Identifier: NCT01942564     History of Changes
Other Study ID Numbers: 2013H0151
W81XWH-12-1-0434 ( Other Grant/Funding Number: Telemedicine and Advanced Technology Research Center )
First Posted: September 16, 2013    Key Record Dates
Last Update Posted: September 25, 2017
Last Verified: September 2017

Keywords provided by Andrew Hartwick, Ohio State University:
traumatic brain injury

Additional relevant MeSH terms:
Wounds and Injuries
Brain Injuries
Brain Injuries, Traumatic
Craniocerebral Trauma
Photosensitivity Disorders
Brain Diseases
Central Nervous System Diseases
Nervous System Diseases
Trauma, Nervous System
Skin Diseases
Vision Disorders
Sensation Disorders
Neurologic Manifestations
Eye Diseases
Signs and Symptoms