Ocular treatment of progressing proliferative diabetic retinopathy is based on retinal laser photocoagulation and pars plana vitrectomy. Improvements in instrumentation and advances in techniques and procedures have increased indications for vitrectomy. These include vitreous haemorrhage preventing laser photocoagulation, severe nonclearing vitreous haemorrhage, subhyaloid and premacular haemorrhage, tractional retinal detachment involving or threatening the macula, combined tractional and rhegmatogenous retinal detachment, progressive fibrovascular proliferation, clinically significant macular oedema and rubeosis iridis. Together with the increasing number of indications, timing for vitrectomy has also changed. The beneficial effect of early vitrectomy for these indications has been clinically shown and supported by several studies. The benefit is evident in case of type I diabetes and when the duration of the diabetes is less than 20 years. Long-term outcomes can therefore be improved when individualised treatment algorithms are applied.