We describe a case that was referred 10 months after Nd:YAG laser treatment with a posteriorly dislocated silicone intraocular lens (IOL) into the vitreous cavity.
Patient: A 70-year old white woman underwent uncomplicated phacoemulsification with in-the-bag placement of a Chiron silicone plate haptic lens through a 5.5- mm continuous circular capsulorhexis. The patient was fine until 9 months postoperatively when she complained of a decrease in visual acuity due to capsular fibrosis. A successful Nd:YAG laser capsulotomy was performed, resulting in an increase in visual acuity. Ten months later, the patient noted acute and atraumatic loss of vision, and the IOL was found to have dislocated posteriorly onto the retina.
Results: The dislocated IOL was removed via the anterior chamber following pars plana vitrectomy. Perfluorocarbon liquid was used to elevate the slippery lens from the retinal surface. The IOL was removed by a Sato Knife from the anterior chamber, followed by implantation of a one-piece PMMA IOL in the ciliary sulcus.
Conclusion: Silicone plate haptic IOLs seem to present special risks for dislocation. Shrinkage of the anterior capsule exerts centripetal forces on the ends of the plate haptic, causing the optic to move posteriorly and to exert pressure against the posterior capsule. If either the posterior or anterior capsule is disrupted by Nd:YAG laser treatment, the forces created by capsular contraction against the flexible lens may cause extension of radial tears and appear to be a substantial risk for further capsule-tearing, releasing the IOL into the vitreous cavity, even months later. The forces of capsular contraction can impart a spring-loading effect on plate haptic silicone lenses. Due to inadequate capsular adherence, these lenses are at risk of posterior dislocation from capsular rents following Nd:YAG laser treatment.