ObjectiveTo observe the effect of preoperative intravitreal ranibizumab injection (IVR) on the operation duration of vitrectomy and postoperative vision for the treatment of proliferative diabetic retinopathy (PDR). MethodsA prospective study was carried out with the 90 PDR patients (90 eyes) who underwent vitrectomy. The 90 patients(90 eyes)were assigned to the vitrectomy only group(43 eyes) and the IVR combined with vitrectomy group (47 eyes). The IVR was performed 5-13 days prior to vitrectomy in the IVR combined with vitrectomy group. There were 15 eyes with fibrous proliferation PDR (FPDR), 16 eyes with advanced PDR (APDR) without involving the macular and 16 eyes with APDR involving the macular in the vitrectomy only group. There were 14 eyes with FPDR, 15 eyes with APDR without involving the macular and 14 eyes with APDR involving the macular patients in the IVR combined with vitrectomy group. All the eyes in the two groups were regularly operated by the same doctor to complete the vitrectomy. The start and end time of vitrectomy were recorded. The average follow-up time was 10 months. The changes of best corrected visual acuity (BCVA) before and 1, 3 and 6 months after surgery were compared between the two groups. ResultsThe duration of operation of the FPDR type (t=-8.300) and the APDR involving the macular type (t=-2.418) in the IVR combined with vitrectomy group was shorter than vitrectomy only group (P < 0.05). The comparison of duration of operation of the APDR without involving the macular type in the two groups has no statistically significant difference (t=-1.685, P > 0.05). At 1 month after surgery, the comparison of BCVA of the IVR combined vitrectomy group and the vitrectomy only group in APDR involving the macular type has no statistically significant difference (t=0.126, P > 0.05). At 3, 6 months after surgery, the BCVA of the IVR combined vitrectomy group in APDR involving the macular type was significantly better than the BCVA of the vitrectomy only group (t=8.014, 7.808; P < 0.05). At 1, 3, and 6 months after surgery, the BCVA of the IVR combined vitrectomy group in FPDR type (t=3.809, 1.831, 0.600) and APDR without involving the macular type (t=0.003, 1.092, 3.931) compared with pre-treatment, the difference were not statistically significant (P > 0.05); the BCVA in APDR without involving the macular type compared with pre-treatment, the difference was distinctly statistically significant (t=2.940, 4.162, 6.446; P < 0.05); the BCVA in APDR involving the macular type (t=0.953, 1.682, 1.835) compared with pre-treatment, the difference were not statistically significant (P > 0.05). ConclusionPreoperative IVR of PDR can shorten the operation duration and improve the BCVA of APDR involving the macular type.