Lens opacities and particularly nuclear sclerosis belong to the most frequent complications after pars plana vitrectomy. Although the causative mechanism is not yet completely understood, the infusion cannula and infusion technique are likely to have important influence on the development of postoperative lens opacities. In order to reduce the flow of the infusion fluid directed to the posterior lens surface we developed a new cannula. Because of its posterior curvature and opening as well as a turbulent flow of the fluid the impairment of the posterior lens surface is diminished. To study the clinical efficacy of the new infusion cannula we examined 235 patients after pars plana vitrectomy during an observation period of 12 months. 14.7% of the total group developed progressive nuclear sclerosis. Significant cataract formation was much less frequent in eyes operated on because of macular pucker (7.3%). This is a lower incidence compared with other investigators.