AIM: To identify factors predicting visual improvement post vitrectomy for sequelae of proliferative diabetic retinopathy (PDR).METHODS: This was a retrospective analysis of pars plana vitrectomy indicated for sequelae of PDR from Jan.to Dec.2014 in Hospital Sultanah Bahiyah,Alor Star,Kedah,Malaysia.Data collected included patient demographics,baseline visual acuity (VA) and post-operative logMAR best corrected VA at 1y.Data analysis was performed with IBM SPSS Statistics Version 22.0.RESULTS: A total of 103 patients were included.The mean age was 51.2y.On multivariable analysis,each pre-operative positive deviation of 1 logMAR from a baseline VA of 0 logMAR was associated with a post-operative improvement of 0.859 logMAR (P<0.001).Likewise,an attached macula pre-operatively was associated with a 0.374 (P=0.003) logMAR improvement post vitrectomy.Absence of iris neovascularisation and absence of post-operative complications were associated with a post vitrectomy improvement in logMAR by 1.126 (P=0.001) and 0.377 (P=0.005) respectively.Absence of long-acting intraocular tamponade was associated with a 0.302 (P=0.010) improvement of logMAR post vitrectomy.CONCLUSION: Factors associated with visual improvement after vitrectomy are poor pre-operative VA,an attached macula,absence of iris neovascularisation,absence of post-operative complications and abstaining from use of long-acting intraocular tamponade.A thorough understanding of the factors predicting visual improvement will facilitate decision-making in vitreoretinal surgery.