RESUMO
This pilot study explored the sensitivity of retinal markers to CNS sequelae of concussive and subconcussive head hits. Three groups of college athletes were assessed at pre-season, post-season and 4-months later: Football players with a concussion history (FB+C) (n = 9), players without a concussion history (FB-C) (n = 11), and non-contact athletes (swimmers, track & field; Non-FB) (n = 12). Measures included optical coherence tomography (OCT), OCT angiography, electroretinography, and visual acuity testing. Head impacts during the season were tracked with in-helmet accelerometers. At pre-season, FB+C demonstrated thicker macular central subfields (CSF) (Hedge's g (effect size) = 1.05, p = 0.02) and retinal nerve fiber layers (RNFL) (g = 0.81, p = 0.08), relative to other athletes. Differences in CSF thickness were also observed at post-season and follow-up (gs > 1.00, ps < 0.04), reflecting their non-short-term nature. RNFL was thicker in FB+C at post-season (g = 0.93, p = 0.06) but not later. Total head impacts during the season correlated with increases in CSF thickness from baseline to follow-up only (r = -0.53, p = 0.02). High intensity head impacts in particular correlated with increases in cup-to-disc ratio at post-season and follow-up (rs > 0.53, ps < 0.03). These data suggest that concussion history is associated with retinal changes that are not short-term, and that severe head impacts are associated with acute changes whose duration is not yet known.
