Intraocular lens movement caused by ciliary muscle contraction

PURPOSE: To investigate intraocular lens (IOL) movement, measured as a change in anterior chamber depth (ACD) caused by pilocarpine-induced ciliary muscle contraction. SETTING: Department of Ophthalmology, University of Vienna, Vienna, Austria. METHODS: In this prospective study, the ACD was measured using high-precision, high-resolution, dual-beam partial coherence interferometry in 62 pseudophakic eyes of 55 patients under pilocarpine- and cyclopentolate-induced ciliary muscle contraction and relaxation. The following were studied: 2 models of a ring-haptic IOL (designed to accommodate), a plate-haptic IOL, and 3 types of 3-piece IOLs. Measurements were performed 3 months after surgery. RESULTS: The ring-haptic IOLs and plate-haptic IOL showed a forward movement (ring haptic 43A, -116 microm; ring haptic 43E, -222 microm; plate haptic -162 microm). The 3-piece IOLs showed no change in ACD except in 1 IOL type in which there was backward movement (156 microm). CONCLUSIONS: Pilocarpine-induced ciliary muscle contraction caused forward movement of ring- and plate-haptic IOLs that resulted in an estimated accommodative amplitude of less than 0.50 diopter in most cases. The accommodating ring-haptic IOLs did not perform better than the conventional plate-haptic IOL.