Purpose: To evaluate the benefits of pars plana vitrectomy (PPV) in subjects with poor visual acuity (VA) and a chronic macula-involving tractional retinal detachment (TRD) secondary to proliferative diabetic retinopathy (PDR). Methods: A retrospective, case-controlled chart review was conducted, and patients were divided into (1) a study group that underwent PPV and (2) a control group in which PPV was declined. Both study and control subjects had a baseline VA of hand motions at 3 feet or worse, a PDR-associated macula-involving TRD for more than 6 months, and at least 12 months of follow-up. Results: A total of 175 subjects were analyzed. There were no differences in baseline characteristics between cohorts. The change in VA was improved by 0.78 logMAR (95% CI, 0.64-0.90) in the study group compared with 0.03 logMAR (95% CI, −0.15 to 0.22) in the control group (P < .0001). The rates of achieving 20/200 or better Snellen VA and 20/50 or better Snellen VA were increased in the study group compared with the control group (P < .0001 and P = .007, respectively), and the rates of becoming no light perception, developing neovascular glaucoma, or undergoing enucleation/evisceration during the study period were higher in the control group compared with the study group (P = .02, P < .0001, and P = .03, respectively). Conclusions: Patients with PDR with poor VA and a macula-involving TRD of more than 6 months duration still may have a more meaningful improvement in vision and fewer adverse events when PPV is performed than when PPV is declined in favor of less invasive options.