Visual outcomes and prognostic factors following 23G vitrectomy for vitreous hemorrhage in eyes with proliferative diabetic retinopathy

| Purpose: We aimed to evaluate the factors influencing the visual gain following pars plana vitrectomy for vitreous hemorrhage in patients with proliferative diabetic retinopathy. Methods: A retrospective study was conducted on 172 eyes of 143 consecutive patients with diabetes mellitus between January 2012 and January 2018. Demographic data, ophthalmological findings, surgery details, and visual outcomes were gathered after consulting the patients' records. The main outcome measured was the improvement of best corrected visual acuity and the secondary outcomes measured were rebleeding and complications. Results: Best corrected visual acuity improved in 103 eyes (59.88%), worsened in 45 eyes (26.16%), and remained unchanged in 24 eyes (13.95%). Type 2 diabetes mellitus was significantly associated with better final best corrected visual acuity (p=0.0244). Previous treatment by pan-retinal laser photocoagulation or intravitreal bevacizumab determined better final best corrected visual acuity, but not significantly (p>0.05). Preoperative rubeosis iridis and neovascular glaucoma did not influence the outcomes. The lack of fibrovascular proliferation requiring dissection was a significant factor for better final best corrected visual acuity (p=0.0006). Rebleeding occurred in 37.1% of the eyes and it was not influenced by the antiplatelet drugs (p>0.05). Postoperative neovascular glaucoma was a negative prognostic factor (p=0.0037). Conclusion: The final best corrected visual acuity was influenced positively by type 2 diabetes mellitus and the absence of preoperative extensive fibrovascular proliferation and negatively by postoperative neovascular glaucoma.