Pupillary dynamics and accommodative response in mild traumatic brain injury.

Purpose: To measure the pupillary dynamics and accommodative response in individuals with mild traumatic brain injury (mTBI) as compared to age-matched controls.

Materials and methods: 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.

Results: 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).

Conclusion: 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.