The author experienced 96 cases of eyeball perforation from January 1980 to May 1982. Of those evaluated 24 cases of severe penetrating injuries involving vitreous gel were treated with pars plana vitrectomy. The conclusions were as follows: 1. Visual improvement was achieved in 45.B%, of the 24 patients with ocular penetrating injury treated by pars plana vitrectomy. 2. The prognosis was poorer in cases with scleral or corneoscleral injury than corneal penetrating injury. 3. The final visual prognosis was poorer in the 8 cases with large scleral laceration (more than 8mm) than in the other 16 cases. The visual acuity was limited to hand motion or less in 12 cases. 4. Those patients who were operated on between 2 weeks and 6 weeks after the injury had a better prognosis than others.