['Dropped nucleus' on cataract extraction].

In 0.1% to 1% of cases cataract extraction is complicated by luxated lens fragments, also known as 'dropped nucleus'. Dropped nucleus can lead to severe complications such as glaucoma or retinal detachment. After incomplete cataract extraction visual acuity is poor. Although a few patients with dropped nucleus may heal with medication alone, pars plana vitrectomy is indicated in most of cases. Pars plana vitrectomy entails the removal of luxated lens fragments and placement of an artificial lens if necessary. It is recommended that pars plana vitrectomy be performed within one to two weeks after cataract extraction. It allows recovery of visual acuity in most of cases. It is important that cataract patients should be informed about the possibility of a dropped nucleus before the extraction.