The Head Injury-associated Photosensitivity and Pupillary Function (HIPP) Study
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.
Traumatic Brain Injury (TBI)
|Study Design:||Observational Model: Case Control
Time Perspective: Cross-Sectional
|Official Title:||The Head Injury-associated Photosensitivity and Pupillary Function (HIPP) Study|
- Pupil Responses [ Time Frame: 2 weeks ] [ Designated as safety issue: No ]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.
- Sleep Rhythms [ Time Frame: 2 weeks ] [ Designated as safety issue: No ]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 ] [ Designated as safety issue: No ]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 ] [ Designated as safety issue: No ]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.
|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)|
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.
Please refer to this study by its ClinicalTrials.gov identifier: NCT01942564
|United States, Ohio|
|College of Optometry|
|Columbus, Ohio, United States, 43210|
|Principal Investigator:||Andrew Hartwick, OD, PhD||Ohio State University|