Pupillary dynamics and accommodative response in mild traumatic brain injury.

Abstract

To measure the pupillary dynamics and accommodative response in individuals with mild traumatic brain injury (mTBI) as compared to age-matched controls. This prospective comparative study was carried out at the neuro-optometry clinic of a tertiary eye care hospital. Sixty-three subjects with a history of mTBI and ninety age-matched controls were enrolled in this study. Subjects in the age range of 18-35 years were included in the study. A comprehensive neuro-optometric assessment was performed followed by pupillary dynamics and accommodation response measurements using NeurOptics® pupillary light reflex™-3000 and Grand-Seiko WAM-5500 binocular accommodation auto ref/keratometer | shigiya machinery works LTD. A statistically significant difference was noticed for constriction percentage (%): 32.73 ± 9.20 versus 39.93 ± 7.36 (P < 0.001), average constriction velocity (mm/s): 2.24 ± 0.85 versus 2.62 ± 0.68 (P = 0.002), maximum constriction velocity (mm/s): 3.82 ± 1.33 versus 4.42 ± 0.93 (P = 0.004) and T75 (recovery period to 75% of the baseline pupillary diameter in sec): 1.38 ± 0.36 versus 2.0 ± 0.82 (P < 0.001) in mTBI compared to age-matched controls. A statistically significant difference was noted for accommodative response (in D) as well as in the sample as compared to age-matched controls: -1.12 ± 0.64 versus - 1.39 ± 0.47 (P < 0.001). Pupillary constriction velocities and accommodative response are significantly affected in mTBI. These findings have important clinical implications in being able to understand the visual symptoms following an mTBI.