Foveal versus eccentric retinal critical flicker frequency in mild traumatic brain injury

BackgroundThe purpose of this study was to assess the critical flicker fusion frequency (CFF) at the fovea and at 10° of horizontal retinal eccentricity and to determine if there was a correlation between CFF and the degree of light and motion sensitivity in individuals with mild traumatic brain injury (TBI).MethodsMean CFF thresholds at the fovea, and 10° to the left and right of the fovea, were obtained in 14 mild TBI and 29 visually normal subjects. A questionnaire was used to quantify the degree of light and motion sensitivity and related factors.ResultsThere was no effect of age on CFF under any test condition in either group, nor was there a relation in the TBI group between reported light or motion sensitivity and CFF. Peripheral CFF values were lower in both populations. Among the TBI subjects, there was a trend for lower peripheral CFF values in the periphery and greater mean variability under all 3 test conditions.ConclusionsDecreased sensitivity and increased variability in CFF measurements in the TBI population can be attributed to damage to the higher visual pathways.