Head Injury, Photophobia, Photosensitivity, Traumatic Brain Injury (TBI)
Conditions
Keywords
traumatic brain injury, photophobia, photosensitivity, pupil
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.
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.
Interventions
None listed
Sponsors
U.S. Army Medical Research and Development Command
Ohio State University
Study design
Observational model
CASE_CONTROL
Time perspective
CROSS_SECTIONAL
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
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)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Pupil Responses | 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
| Measure | Time frame | Description |
|---|---|---|
| Sleep Rhythms | 2 weeks | Daily rhythms of sleep and activity will be assessed in subjects with prior brain injury and compared to matched controls. |
| Light Exposure | 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 | 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. |
Countries
United States
Outcome results
None listed