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

Study Overview
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Brief Summary
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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
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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.

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

Conditions
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Head Injury, Traumatic Brain Injury (TBI), Photosensitivity, Photophobia

Participation Criteria
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Eligibility Criteria
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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)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Case Subjects<br>Age 18 years or older Had a head injury that occurred at least 6 months prior to entering study Have found lights more bothersome since injury | |
| Control Subjects<br>Age 18 years or older Have not had a previous head injury Have had a full eye examination at Ohio State University College of Optometry during last 6 months. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pupil Responses | 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. | 2 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sleep Rhythms | Daily rhythms of sleep and activity will be assessed in subjects with prior brain injury and compared to matched controls. | 2 weeks | 
| Light Exposure | 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. | 2 weeks | 
| Photosensitivity Symptoms | 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. | Single visit - one day | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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traumatic brain injury, photophobia, photosensitivity, pupil