Primary visual pathway changes in individuals with chronic mild traumatic brain injury
Reviewed by James Kirkpatrick

Patients with mild traumatic brain injury (mTBI) often self-report vision disturbance despite showing no reduction of visual acuity or fundus examination abnormality. This prospective, observational, cross-sectional study aimed to determine if using a sweeping array of investigations can help diagnose visual dysfunction in patients with mTBI. Twenty-eight participants with head trauma >3 months ago with no ocular, neurological or psychological disease were compared with 28 controls without mTBI. The investigations included oculomotor testing (near point of convergence and prism conversion test), accommodation testing (near point of accommodation, accommodation amplitude) Humphrey visual fields, contrast sensitivity, visual evoked potential (VEP) testing, optical coherence tomography, MRI optic nerve and diffusion MRI (whole brain). Oculomotor and accommodation testing alone did not identify abnormalities in all patients with mTBI reporting visual changes. Conversely, some participants reporting no visual disturbance were found to have abnormalities on oculomotor and accommodation testing. Contrast sensitivity was decreased in both monocular and binocular conditions in mTBI, driven primarily by a small subset (14%) of participants. No significant differences compared to controls were seen in the overall thickness of the peripapillary retinal nerve fibre layer, Humphrey visual fields or VEP amplitude. A total of four of 28 participants (14%) with mild TBI showed significant regional brain volume differences in distinct areas but no gross differences in optic radiations were detectable between controls. However, when machine learning was applied to the optic radiations and cortical visual areas, 70% of participants with mTBI were identified as having abnormal findings in the posterior visual pathway. By assessing the entire primary visual pathway, along with ocular motor and accommodation changes, 78% of participants with mTBI were identified as having some abnormal findings. Limitations include the small study size, the observational study design and that the number of mTBI and time since the injury were not controlled. This interesting pilot study shows mTBI caused abnormalities throughout the visual pathway in 78% of patients with and without visual symptoms, however larger studies are needed. It shows the potential importance of comprehensive visual assessments in patients with mild TBI.

Primary visual pathway changes in individuals with chronic mild traumatic brain injury.
Rasdall MA, Cho C, Stahl AN, et al.
JAMA OPHTHALMOLOGY
2025;143(1):33–42.