An 18 years old boy was admitted with a rare type of severely dislocated fracture of the posteriolateral aspect of the right orbital wall. At admission ophthalmologic examination revealed no light reception whereas neurophysiological testing showed a normal retinal response (ERG) and a pathological but still reproducible VEP (flash). Immediate surgical intervention and high dose corticoid therapy (methylprednisolon: bolus injection: 30mg/kg body weight and subsequent 5.4mg/kg body weight) led to full clinical and neurophysiological recovery of the optical nerve function after complete unilateral blindness within the following 2 hours. In addition to clinical examination and radiological diagnosis initial neurophysiological testing (ERG, VEP) of the retinal and optical nerve function are essential in order to obtain adequate information for the necessary therapeutic procedure in case of severe trauma of the orbita. Keywords: optic nerve, VEP, trauma, fracture