Evaluating functional outcomes in diabetic vitreous hemorrhage: Comparative analysis of diabetes type and adjunctive preoperative factors

Abstract: PURPOSE: The purpose of this study was to evaluate visual outcomes following pars plana vitrectomy (PPV) in diabetic patients with vitreous hemorrhage (VH), comparing type 1 and type 2 diabetes mellitus, and to assess the influence of preoperative intravitreal bevacizumab (IVB) on postoperative visual recovery. METHODS: This retrospective study included 204 eyes from diabetic patients who underwent PPV for nonclearing VH between January 2021 and March 2025. Patients were categorized by diabetes type and stratified according to preoperative IVB administration. Best-corrected visual acuity (BCVA) was recorded preoperatively and at 1 st and 3 rd postoperative months. Visual acuity values were converted to the logarithm of the minimum angle of resolution for analysis. Statistical tests included paired and independent t -tests, Wilcoxon signed-rank test, Mann–Whitney U test, and Chi-square test, with P < 0.05 considered statistically significant. RESULTS: Significant postoperative BCVA improvement was observed in both diabetic subgroups ( P < 0.001). Type 2 diabetic eyes exhibited greater median visual gain overall. In type 1 diabetic patients, those receiving preoperative IVB showed more pronounced visual improvement at 3 months compared to untreated counterparts, although intergroup differences did not reach statistical significance. In type 2 diabetics, the additional benefit of IVB was limited. No major intraoperative complications or cases of endophthalmitis occurred. CONCLUSION: PPV is effective in restoring vision in both type 1 and type 2 diabetic VH. Type 2 diabetics tend to achieve more consistent visual gains, while type 1 diabetics may benefit more substantially from adjunctive preoperative IVB. These findings support individualized perioperative planning in diabetic VH management.