We reviewed 194 consecutive eyes treated by pars plana vitrectomy for severe injury with posterior segment involvement. By using multivariate analysis, we determined which of a large number of clinical, ultrasonographic, and electrophysiologic factors influenced or predicted postoperative visual acuity. Additionally, the effects of the timing of vitrectomy on final vision and the usefulness of prophylactic scleral buckling were analyzed. We found that although clinical data have predictive value, it is electrophysiological information, specifically the visual-evoked potential, which most accurately predicts the postoperative vision of an injured eye. We could not demonstrate a significant effect of the timing of surgery on the final visual result but could determine that prophylactic scleral buckling clearly reduces the rate of delayed retinal detachments.