- April 07, 2022
“Physicians have measured [pupillary light reflex (PLR)] since the earliest time of recorded history,” lead study author Frederick Robert Carrick, DC, PhD, MS-HPEd, Professor of Neurology at the University of Central Florida College of Medicine, said in a press release. “It is only recently that advances in technology have allowed us to quantify it accurately. This is the largest study of concussion and PLR to date.”
The application, Reflex, was developed by health care technology company BrightLamp. It uses a digital video recording to measure PLR, with the user holding the camera up to an eye and tapping the smartphone screen, which flashes a light to initiate a pupil response. The FDA has classified the application as a class 1 510(k) exempt regulated medical device.
Carrick and colleagues used the BrightLamp Reflex iPhone application to conduct a retrospective clinical review of patients’ PLR.
Results showed the PLR variables of latency, maximum pupil diameter, minimum pupil diameter, maximum constriction velocity and the 75% recovery time correlated with significant differences between patients with a concussion and those without one. Further, the researchers noted significant differences in PLR metrics over the life span and between genders and patients with and without symptoms. Concussion history, gender and the presence of symptoms linked to a head injury modulated differences in PLR metrics. “The metrics obtained from the PLR can assist in determining whether a patient has suffered a concussion regardless of symptomatology,” Carrick and colleagues wrote. “As a physiological measurement, the PLR is not affected by subjective interpretation and might be incorporated as a valuable biomarker of brain functional status.”
REFERENCE: Healio Nurology; 22 NOV 2021; Joe Gramigna, MA