US Army Investigators say they have found a fast and simple eye test for identifying acute mild traumatic brain injury which could improve diagnosis methods for mild forms of brain injury that often go unnoticed.
Mild traumatic brain injury makes up the vast majority of concussions but it often goes undiagnosed due to the more subtle symptoms and shorter recovery time. But, researchers from the Department of Optometry at the Womack Army Medical Center in Fort Bragg, North Carolina say it is important these injuries are identified to prevent complications or further injury.
To help make mild traumatic brain injuries easier to identify in the field, the team began looking into the biologic responses to TBI that are able to be observed in the eye.
“We have identified functional divergences that could be biomarkers for traumatic brain injury,” said José Capó-Aponte, OD, PhD, from the Womack Army Medical Center. “The next step will be to take those selected components and create an algorithm or calculator” that will estimate the likelihood of a traumatic brain injury, he told Medscape Medical News.
Dr. Capó-Aponte presented the findings at the Optometry’s Meeting by the American Optometric Association. The team says they were encouraged to investigate responses to the injury in the eye and related nerve systems because TBI often affects areas of the brain related to vision.
“Since approximately 30 areas of the brain and seven of the 12 cranial nerves deal with vision, it is not unexpected that the patient with traumatic brain injury may manifest a host of visual problems, such as papillary deficit, visual processing delays, and impaired oculomotor tracking and related oculomotor-based reading dysfunctions,” Dr. Capó-Aponte explained.
After reviewing existing research, the team decided to focus on conjugate binocular eye movements (versions) and disconjugate movements (vergences) as possible biomarkers. They then tested this idea using a 10-minute test that included three eye measurements and one visual symptoms questionnaire.
For the study, 2000 active-duty military personnel 19 to 44 years of age were evaluated using the eye test. Of those, 87 men and 21 women had been diagnosed with a mild traumatic brain injury or concussion within the past 72 hours.
The tests included measuring the pupil’s response to light, including measuring maximum and minimum pupil diameters, percentage of restriction, constriction latency, average and maximum constriction velocity, average dilation velocity, and time to 75% recovery of dilation. They also tested near-point conversion with a 20/30 Snellen test and saccadic eye movement function using the King-Devick Test.
According to the results, average constriction velocity, average dilation velocity, and 75% dilation recovery time were all significantly different between those who had mild traumatic brain injury and control subjects involved in the test. Injured participants also showed notably higher near-point convergence scores, longer times to complete the King-Devick Test, and more symptoms on the visual symptoms questionnaire.
“We have been searching for the one thing that will allow us to diagnose the presence of a concussion as quickly as possible after the incident,” said poster moderator Dominick Maino, MD, professor of pediatrics and binocular vision at the Illinois College of Optometry and Illinois Eye Institute in Chicago.
“With the test described by Dr. Capó-Aponte, we would have a device that could be easily taught to others, is relatively inexpensive, and would give us immediate feedback on the presence of a concussion,” he said.
“Then we can get that individual into treatment as soon as possible, knowing this concussion is present, with all of the ways that it adversely affects the oculovisual system for the individual and their quality of life,” Dr. Maino told Medscape Medical News.