RESUMEN
<p><b>OBJECTIVE</b>To examine the prognosis of preretinal hemorrhage following vitrectomy and silicone oil tamponade for severe proliferative diabetic retinopathy.</p><p><b>METHODS</b>Clinical data of 76 cases of proliferative diabetic retinopathy treated with vitrectomy and silicone oil infusion tamponade in Sir Run Run Shaw Hospital from October 2006 to September 2013 were retrospectively reviewed. Intraoperative bleeding,postoperative preretinal bleeding,blood reabsorption time, and preretinal fibrosis were assessed.</p><p><b>RESULTS</b>All preretinal hemorrhage developed within 1 week after surgery, blood was distributed in thin and scattered patterns (32 cases), thick and localized patterns (25 cases) or thick and scattered patterns (19 cases). The preretinal hemorrhage was ceased in 1 day after operation in 35 cases, in 2 days after operation in 18 cases, in two weeks after operation in 23 case. Recurrent hemorrhage occurred within 1 week after operation in 15 cases. Thin blood was largely reabsorbed in about two weeks, and thick blood was largely reabsorbed in about five weeks. Fibrosis tissue was resulted in 15 cases(34.1%) with thick blood.</p><p><b>CONCLUSION</b>Most of preretinal hemorrhage occurs within 1 week after surgery and is reabsorpted with 5 weeks in patients with proliferative diabetic retinopathy undergoing vitrectomy and silicone oil tamponade. The major complication of preretinal bleeding is the formation of preretinal fibrosis.</p>