BACKGROUND In phacic eyes the development of a cataract is induced by silicon oil. In this case the lens has to be removed in a second operation with or without intraocular lens implantation. In cataract surgery a new incision technique is used, which makes it easily possible to combine both operations in one session. METHODS A feature of the new incision technique is that a scleral tunnel is dissected before the anterior chamber is opened. The opening closes itself, if the intraocular pressure rises. The danger, that a rise in intraocular pressure during the vitrectomy makes an irisprolaps, for example during the substitution of perfluorcarbon by silicon oil, no longer exists. RESULTS The operation technique and the postoperative course of three patients with intraocular lens implantation and pars-plana-vitrectomy using silicon oil is reported. CONCLUSIONS By using the new incision technique in cataract surgery intraoperative complications during vitrectomy like an irisprolaps or penetration of silicon oil into the anterior chamber no longer exist. In selected cases one operation is saved for the patient.