Inclusion Criteria:  1. Provide documented informed consent or assent along with guardian consent. 2. Have presented, at any time post injury, for any complaint related to an injury involving either a direct force to the head or a blow to the body that has the potential to transmit a rapid acceleration/deceleration of the head, with or without loss of consciousness, with or without external signs of head injury. 3. Be 5 to 67 years of age, inclusive. 4. Have the ability to provide a complete ophthalmologic, medical, and neurologic history as well as report current medications.  Exclusion Criteria:  1. Have penetrating trauma or known skull fracture or intracranial injury. 2. Have had a conventional head CT or MRI demonstrating evidence of structural brain injury (subdural, epidural or intraparenchymal hemorrhage, edema/mass effect per attending radiologist read). 3. Any of the following conditions, immediately related to the incident injury: loss of consciousness exceeding 30 minutes or best available Glasgow Coma Scale (GCS) score less than 13 within 24 hours or other acute conditions requiring emergency medical management. 4. Be blind (no light perception), have missing or non-functional eyes. 5. Be unable to open their eyes. 6. Have a history of unresolved strabismus, diplopia, amblyopia. 7. Have a history of unresolved cranial nerve III, IV, or VI palsy. 8. Have a history of unresolved macular edema, retinal degeneration, extensive cataract, or ocular globe disruption. 9. Have a history of extensive prior eye surgery or scarring (examples include strabismus surgery, scleral buckle repair of retinal detachment, repair of blow out fractures of the orbit and any procedures that would interfere with extraocular muscle movements; prior cataract surgery or Lasik are not exclusions). 10. Have a prior history of unresolved ocular-motor dysfunctions. 11. Be intoxicated.