Transient Post-Traumatic Blindness

Transient Post-Traumatic Blindness

Tobias Becker, MD

• CASE A 13-year-old girl is struck by a vehicle while riding on a bicycle without a helmet. Bystanders stated that she was unconscious for about 3 minutes.  On scene, she is alert and appropriate and complaining of a mild headache. She is noted to have a bleeding wound above her right ear. She states that she is unable to see anything and a brief exam in the field appears to confirm this. After 15 minutes, on a repeat exam before transport, her vision began to return and was almost completely restored by the time she arrived in the ED. CT revealed a small epidural hematoma, which was managed nonoperatively. Several days later, she remains well with normal vision.

PEARLS

• Post-traumatic transient cortical blindness is a very rare but well described syndrome, with case reports dating from 1918. It is more common in children and generally has a good prognosis.
  • Gleeson AP, Beattie TF. Post-traumatic transient cortical blindness in children: a report of four cases and a review of the literature. J Accid Emerg Med. 1994 Dec; 11(4): 250–252.
  • This is a type of cortical blindness, not a result of ocular pathology. Although the patient may report various degrees of blindness, the pupils will react normally to light.
  • Some cases occur after seemingly minor head injury.
  • Blindness may occur immediately following injury or after several minutes. It usually resolves within hours.
  • It may be associated with vasospasm of the occipital vessels and related ischemia as well as a higher risk of migraine in later life.
  • The differential diagnosis includes anxiety as well as non-traumatic causes of cortical blindness including shock, cervical spine fracture with vertebral artery injury, stroke, meningitis, and CO poisoning.
  • Optokinetic testing may help identify functional or causes.
    • Patients with psychogenic blindness demonstrate saccadic eye movements as the patient’s involuntarily tracks a moving object (typically a sheet of paper of a drum with striped lines).