Purpose: To analyze the clinical presentation and implications of cavity or schisis formation in the MemoryLens (CIBA Vision) intraocular lens (IOL) optic. Setting: Eye Department, Red Cross Hospital, Munich, Germany. Methods: This study was a retrospective chart review and slitlamp photography analysis of IOL schisis. Results: Four patients with IOL schisis were identified and their charts analyzed. Clinically, the schisis presented as a sharply demarcated round structure. The aspect was clear on coaxial illumination, but on tangential illumination the schisis area was opaque. Patients experienced glare, foggy vision, and deteriorated visual function or had no symptoms. One patient lost visual acuity, and the IOL was explanted. Conclusions: Clinically, IOL schisis was easily differentiated from cases of IOL opacification due to calcification. The clinical implication was not uniform, ranging from no symptoms to great visual disturbance leading to explantation of the IOL. The cause of this complication remains unclear. A possible explanation is the impact of solvent-induced tensile stress on the IOL optic material during the manufacturing process.