Traumatic brain injuries may be linked to RNFL loss.

Brain imaging techniques are not able to reliably detect neuronal degradation caused by traumatic brain injury (TBI). Researchers noted that they believe the retina may be an accessible site to identify alterations to neural tissue after TBI. Their study examined whether multiple TBIs in young subjects elicit structural changes in the macula and retinal nerve fiber layer (RNFL).

From 10 adult patients with a history of at least two mild or moderate TBIs (80% female, average age: 26.1) compared with 10 age- and sex-matched controls with no TBI history, the researchers acquired OCT images of the macula and peripapillary RNFL. Scanning laser polarimetry (SLP) with variable corneal compensation was also used to image the macula and peripapillary RNFL.

The case subjects reported an average of 3.3 TBIs over a range of one to 18 years prior. The study noted no differences in minimal foveal thickness or macular phase retardation between the groups. There were no differences in OCT-measured global, temporal, temporal-superior, nasal-superior, nasal or temporal-inferior RNFL thicknesses between the groups; however, nasal-inferior RNFL thickness was significantly lower in case subjects (97.1µm) than in control subjects (118µm). Similarly, the SLP-measured inferior average was significantly lower in case subjects (56.6µm) vs. control subjects (60.7µm). The temporal-superior-nasal-inferior-temporal (TSNIT) average was also significantly lower in case subjects (62.9µm) vs. control subjects (68.5µm). There were no differences between the groups for SLP parameters superior average, TSNIT standard deviation and nerve fiber index.

“Our results agree with reports in the literature of RNFL thinning in male collision-sport athletes,” noted Elizabeth Stern-Green, third-year OD/MS student at the Ohio State University College of Optometry. “These outcomes support the eye’s potential as a site to objectively detect structural changes to neural tissue after TBI.”

Stern-Green E, Shelton E, Day E, et al. Retinal nerve fiber layer degradation in subjects with a history of multiple traumatic brain injuries. AAO Meeting 2021.