Abstract
Traumatic brain injury (TBI) has negative short and long term consequences for the visual function, including vision loss and visual disturbances. However, the true magnitude and significance of the visual function deficits related to TBI have become apparent only in recent years after the publication of several small scale reports mostly from studies of military populations, some of which have suggested that more than 60% of the patients could experience vision impairment post TBI. Thus the correct diagnosis and interpretation of the visual symptoms post TBI is very important. That prompted us to examine published studies of psychophysical (visual acuity, visual field, contrast sensitivity, color vision etc.) and electrodiagnostic tests (ERG and VEP) with regard to their value in predicting the visual outcome from head injury by a comprehensive search of electronic databases (PubMed, Psych Info and Web of Science) using keywords for head trauma, visual acuity, visual field, ERG, VEP, etc. Among psychophysical tests, most studies reported transient and dynamic visual field defects and only few studies reported changes in other functions like contrast sensitivity and color vision. Oculomotor tests seem to be widely used and typically report convergence insufficiency associated with cranial nerve palsies and photosensitivity. Finally, objective electrophysiological tests (mostly pattern and flash VEP) found good correlation between unfavorable visual outcome and VEP parameters (amplitudes and timing of the peaks), but the studies differed widely in methodology and none of the data were obtained after the introduction of the international standards for the test. The significance of each group of tests will be discussed.