Evaluation of the magnetic properties of cosmetic contact lenses with a superconducting quantum interference device

Abstract

We evaluated the magnetization of 21 cosmetic contact lens samples that included various coloring materials with a superconducting quantum interference device with regard to magnetic resonance (MR) safety. We found 7 samples were ferromagnetic; two had both ferromagnetic and diamagnetic properties; and the rest were diamagnetic. The saturated magnetization of the most ferromagnetic sample was 15.0 μJ/T, which yielded a magnetically induced displacement force of 90.0 μN when the spatial gradient of the static magnetic field was 6.0 T/m. The force was less than one-third of the gravitational force.