Quantifying Visual Photosensitivity in Veterans with Traumatic Brain Injury

Abstract

Purpose : Traumatic brain injury (TBI) is a significant health issue which affects service members and veterans during times of both peace and war. The Department of Defense and the Defense and Veteran's Brain Injury Center estimate that 22% of all combat casualties are brain injuries. The purpose of this study was to determine if visual photosensitivity thresholds (VPT) in veterans with TBI could be quantified using the Ocular Photosensitivity Analyzer (OPA) and compare the results with healthy subjects.

Methods : The OPA (Aguilar MC, et al. IOVS, 2016; 57(12):622) produces a light stimuli with varying intensities from 1 to 32,000 lux (0 to 4.51 log lux). The subject is instructed by the OPA to indicate whether the light stimulus is “uncomfortable” by pressing a hand-held button. After 10 response reversals, the VPT is automatically calculated. To ensure reliability, catch trials were incorporated throughout the test. We compared the VPT of healthy and TBI subjects presenting with light sensitivity symptoms. Three TBI subjects (3 males, age = 64 ± 19) with occurrence of injuries varying in time (2-6 decades), and nine healthy subjects (5 females and 4 males, age = 31.4 ± 7.6) were tested under an IRB approved protocol.

Results : The healthy and TBI subjects were found to have a mean predicted VPT of 3.24±0.63 and 0.35±0.61 log lux, respectively. A one-way analysis of variance showed a statistically significant difference (p<0.0001) between the healthy and TBI subject groups.

Conclusions : The OPA is a safe and sensitive instrument capable of determining VPT in both healthy and TBI subjects. The findings demonstrate a significant difference in VPT between the groups. Ongoing studies are being performed with the OPA to increase our subject population and further validate our findings. Furthermore, as treatments for TBI are being developed the OPA has the potential to be utilized as an outcome measure in studies that would warrant a pre-treatment baseline and post-treatment VPT.

Acknowledgements: Supported in part by: NEI R24 EY022023, DAMD-W81XWH-09-1-0675, DOD Warfighters W81XWH-13-1-0048, Florida Lions Eye Bank, Drs. KR Olsen & ME Hildebrandt, Drs. Raksha Urs & Aaron Furtado, Brien Holden Vision Institute, NIH P30EY14801, Research to Prevent Blindness, Henri and Flore Lesieur Foundation (JMP). Technical support provided by: F Manns, DH Sliney, C de Freitas, K Alawa, A Arboleda, A Bernal, J Silgado, N Salas, N Relhan, & WJ Feuer.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.