In this retrospective study, medical records of all patients with IOL related problems after implantation of one hydrophilic acrylic single-piece lens at the Department of Ophthalmology Graz, Medical University Graz, Styria, Austria are reviewed. Characteristics and predisposing factors for late in-the-bag, out-of-the-bag IOL dislocations, and haptic complications will be investigated and compared amongst each other or control patients. Incidence rates for each IOL complication will be calculated. For in-the-bag dislocations odds ratios for each predisposing factor will be calculated.