[Spontaneous dislocation of a silicone disk lens 4 months postoperative into the vitreous body]

We report on a patient who experienced an acute deterioration in visual acuity at night four months after implantation of a silicon-disc lens into the capsular bag. On examination, the artificial lens was localized preretinally. The capsular equator was fibrous, but had retained its circular shape. The posterior capsule was ruptured. The rupture may be explained by tension in the posterior capsule, which is only 1-4 microns thick, within the shrunken capsular bag, and by an acute increase of intraocular pressure caused by rubbing of the eyes during sleep.