Blunt head injury frequently results in visual impairment, the optimal treatment of which is still debated. Over a 5-year-period (1987-1991) 111 patients with indirect optic nerve injury resulting from closed head trauma have been treated. In each case loss of vision was the only neurological deficit. In group A, 66 patients were initially treated with large doses of prednisolone (80 mg/day) for 3 weeks. Twenty-seven patients improved on steroids alone. In the remaining 39 patients in whom either unsatisfactory or no improvement occurred a transethmoidal optic nerve decompression was performed. Twenty-two patients in the latter group improved, thus yielding an overall improvement rate of 74.2% in group A. Group B (control), in which 45 patients were treated with prednisolone only (80 mg/day for 3 weeks), had an overall improvement rate of 51% (23 patients). The study reveals that while nearly half of such patients can improve on steroids alone, optic nerve decompression significantly improves recovery rates in patients where conservative treatment is unsatisfactory (P < 0.05). Total loss of vision not responding to steroids, absence of waveform on visual evoked response, and presence of an optic canal fracture indicate a poor prognosis.