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

The recruitment status of this study is unknown. The completion date has passed and the status has not been verified in more than two years.
Verified October 2014 by Ohio State University.
Recruitment status was:  Active, not recruiting
U.S. Army Medical Research and Materiel Command
Information provided by (Responsible Party):
Andrew Hartwick, Ohio State University Identifier:
First received: September 6, 2013
Last updated: October 21, 2014
Last verified: October 2014
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.

Head Injury
Traumatic Brain Injury (TBI)

Study Type: Observational
Study Design: Observational Model: Case Control
Time Perspective: Cross-Sectional
Official Title: The Head Injury-associated Photosensitivity and Pupillary Function (HIPP) Study

Resource links provided by NLM:

Further study details as provided by Ohio State University:

Primary Outcome Measures:
  • 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:
  • 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.

  • 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.

  • 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.

Estimated Enrollment: 80
Study Start Date: August 2013
Estimated Study Completion Date: December 2014
Estimated Primary Completion Date: December 2014 (Final data collection date for primary outcome measure)
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.

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.


Ages Eligible for Study:   18 Years and older   (Adult, Senior)
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)
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: 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
  More Information

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 )
Study First Received: September 6, 2013
Last Updated: October 21, 2014

Keywords provided by Ohio State University:
traumatic brain injury

Additional relevant MeSH terms:
Wounds and Injuries
Brain Injuries
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 processed this record on May 22, 2017