Optical coherence tomography retinal biomarkers for traumatic brain injuries: a systematic review and meta-analysis.
Abolfazl Hassani, Lydia Gultom, Timothy Liang et al.
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In 30 seconds
This systematic review and meta-analysis assessed OCT-derived retinal measures as potential biomarkers of traumatic brain injury (TBI), comparing people with TBI and controls across seven studies of athletes, veterans, and people with mild-to-moderate TBI. Peripapillary retinal nerve fibre layer (RNFL) findings varied across studies. The pooled analysis found a small, non-significant global effect (Hedges' g = -0.21; 95% CI -2.51 to 0.33; p = 0.84), despite an estimated 1-1.5 µm of RNFL thinning in TBI cases. Some subgroups showed reduced RNFL or other retinal measures, but results were not consistent.
Key findings
- Across studies, peripapillary RNFL differences ranged from minor thickening (+1.7 µm) to pronounced thinning (-14 µm) relative to controls.
- The pooled global effect was non-significant (Hedges' g = -0.21; 95% CI -2.51 to 0.33; p = 0.84).
- Veterans showed faster longitudinal RNFL loss (-1.47 ± 0.24 µm/year vs - 0.31 ± 0.32 µm/year; p = 0.004).
- Boxers had a thinner ganglion cell complex than controls (76.7 ± 2.1 µm vs 81.6 ± 0.5 µm; p = 0.02).
Why it matters
OCT offers a non-invasive way to examine retinal structures that may reflect cerebral pathology, making retinal measures of interest in TBI research. However, the heterogeneous RNFL findings and non-significant pooled result mean that current evidence does not establish a consistent retinal signature. Distinguishing subgroup-specific changes from reproducible biomarkers will require further longitudinal study.
What to keep in mind
Only seven studies were included, and retinal findings varied across populations and measures; the pooled effect was non-significant.