Journal of Rehabilitation Research and Development
2014: 51; 71 80
Reviewed by: Tina Esposito, OD
Midwestern University Arizona College of Optometry
Traumatic Brain Injuries (TBI) are defined as an “alteration in brain function, or other evidence of brain pathology, caused by an external force”. The Department of Defense reports that over 250,000 service members have been diagnosed with traumatic brain injury since the conflicts in Afghanistan and Iraq. That equates to roughly 542 cases of newly diagnosed TBI per month over the last 5 years. Some of the most common symptoms reported by patients are blurred vision, diplopia, headaches, dizziness, poor concentration, an inability to sustain visual attention, photophobia, movement of print, and difficulty when reading. Some of the more common findings with TBI patients are convergence insufficiency and eye movement disorders. This purpose of this retrospective study was to investigate the long-term visual dysfunction in patients after blast-induced mild traumatic brain injury (mbTBI).
Out of the 192 patients with the diagnosis of TBI that presented to the VA for an evaluation, 31 were identified with mbTBI without eye injuries. The inclusion criteria included all servicemen diagnosed with mbTBI longer than 12 months prior to the eye examination and no history of eye injury. The date of the injury, mechanism of injury (mounted vs. dismounted, LOC), age of injury, time since injury, medications, visual symptoms, visual acuity, employment status, and documented eye examination results were all reviewed and analyzed.
After reviewing the data, 94% of patients were male and the mean age at the time of the injury was 30.5 +/-8.3 yrs. Fifty-eight percent occurred while they were dismounted and 42% were inside a vehicle during the injury. The mean interval between the mbTBI and the eye examination was 50.5 +/- 19.9 months. Medications were taken by 14 of the patients in the study. It was noted that patients who did not take any medications had fewer visual symptoms than patients who were on medications; however, this was not found to be statistically significant. Overall, 68% of patients had visual complaints. The most common symptoms were photophobia (55%) and difficulty with reading (32%). Of all patients, 25% were diagnosed with convergence insufficiency and 23% had accommodative insufficiency. Patients with more than one mbTBI had a higher rate of visual complaints (87.5%).
In summary, chronic visual dysfunction and symptoms are present in veteran’s even years after a mild blast traumatic brain injury despite having 20/20 distance visual acuity. It is believed that it takes roughly 5-6 years for the symptoms to improve following an injury. Assessment of symptoms and binocular vision testing should be done routinely during eye examinations to recognize visual problems in this population.