Health effects due to static magnetic fields include visual effects. Which statement is true?

• A. Visual effects
• B. Only auditory effects
• C. No effects
• D. Peripheral nerve effects

Answer: (A)

Static magnetic fields can cause visual sensations due to the interaction of the field with moving charges in the eye. When someone moves in a strong static field, the Lorentz force acts on ions in the retina and surrounding fluids, producing transient electrical stimulation that the brain interprets as light. This results in phosphenes—brief flashes or shimmering lights—reported by people undergoing MRI or other strong static fields. That visual effect is a recognized health effect of static magnetic fields, so the statement describing visual effects as part of the health effects is true. Other potential effects, like vestibular sensations, can occur as well, but peripheral nerve stimulation or exclusive reliance on auditory effects aren’t the primary, documented outcomes in this context.