Between 1997 and 2007, we have conducted eye surgery on 72 patients (i.e. 72 eyes) as a consequence of proliferative diabetic retinopathy complications. The patients' average age was 61; the follow-up observations were carried out over a period of one year after the surgery. When we compare the initial vision with the visual acuity measured during the last follow-up examination in the late post-operative period, i.e. one year after the surgery, we can conclude that the vision of46 eyes (63%) had improved, 17 eyes (24%) did not show any change in vision, and the vision of nine eyes (13%) had deteriorated. Visual acuity of 1/60 (metric system) or better was found in 55 eyes (76%) during the late post-operative period; 6/60 vision or better was found in 29 eyes (40%), and four eyes (6%) showed 6/12 vision or better. If we compare the vision in the early post-operative period with the visual acuity during the last follow-up examination in the late post-operative period, we can conclude that in most cases, i.e. in 45 eyes (62.5%), the vision did not change any further during the months after the surgery, and one eye (1.5%) even showed improvement in visual acuity. It was confirmed that a positive result of pars plana vitrectomy observed in the early post-operative period may indeed persist even during the following months and years of the patient's life.