Spontaneous posterior dislocation of intraocular lenses fixated in the capsular bag.

We report 4 cases of complete posterior dislocation of an intraocular lens (IOL) in the capsular bag occurring a mean of 5.5 years after uneventful cataract surgery. In all 4 cases, posterior chamber IOLs were fixated within the capsulorhexis. The patients experienced sudden loss of vision without an episode of trauma or ocular disease. Using a 3-port pars plana vitrectomy, the IOLs were explanted through a limbal incision and a new IOL was sutured to the ciliary sulcus. Histological examination indicated that zonular fibers were severed at the site of insertion in the capsule.