Pattern- and flash-evoked potentials in the assessment and management of optic nerve gliomas.

Visual evoked potentials were recorded in 25 young patients with optic nerve glioma. In only eight patients could pattern responses be recorded from the affected eyes and these were invariably abnormal. In nine cases with no pattern responses it was still possible to elicit flash responses from the affected eyes. Six patients showed pattern evoked potential changes indicating involvement of fibres from the fellow eye crossing at the chiasm. Serial recording showed a remarkable improvement in the pattern responses of two patients. Flash responses were far less sensitive and less reliable than pattern responses in monitoring patients.