The role of visual evoked potentials in the diagnosis of optic nerve injury as a result of mild head trauma.

The curve of visual evoked potentials was observed and compared with changes of visual acuity and visual field during a 24-month period in a group of 39 patients with optic nerve injury as a result of mild cerebral trauma. Results of the study showed great improvement of visual acuity and visual field after treatment, and slower and continuous improvement of visual evoked potentials. The main abnormality of visual evoked potentials is the shortening of amplitude, which is recorded to gradually recede after treatment in half of the patients. Authors conclude that the shortening of amplitude can be partially explained by the edema and the compression of fibers in the optic canal. Also, they emphasize that in this type of optic nerve injury visual acuity testing is the best indicator of the promptness and scope of the injury, while visual field research presents the best method for following later delicate changes of visual function.