Epidemiological Trends of Traumatic Optic Nerve Injuries in the Largest Canadian Adult Trauma Center

Background: There has been a paucity of information on the epidemiology of traumatic optic neuropathy (TON). This study documents epidemiology of TON over 2 decades in the largest level I adult trauma center in Canada. Methods: Data on all the trauma patients admitted to Sunnybrook Health Sciences Centre from 1986 to 2007 were collected in a prospective database. The aggregate data on optic nerve injuries including demographic data, etiology, Injury Severity Score (ISS), and associated head and facial injuries were recorded. These were analyzed using univariate and multivariate techniques to summarize the association of different variables with TON. Results: During the study period, 0.4% of all trauma patients had TON. The respective demographics for TON group were as follows: male, 76%; median for age, 33.5 years; length of hospital stay, 14 days; ISS, 32; and case fatality, 14%. About two thirds of patients with TON had associated significant head injuries. Conversely, 2.3% of patients with head injury had TON. The relative incidence of TON per year has remained variable from 0% to 1.2%. Motorized vehicle accidents remained the main etiology of TON (63%), but fall had the highest relative frequency leading to TON. In univariate analysis, both ISS and significant head injury were associated with TON. In multivariate analysis, TON was associated with only nasoethmoid complex fractures and significant head injury. Conclusions: These data provide useful information on the frequency and etiologies of TON. It also highlights the importance of studies on better diagnostic tools for TON.