Reading in Dim Light or Darkness Permanently Damages Your Eyes

Reading in low light causes temporary eye strain and discomfort but doesn't cause permanent vision damage. Your eyes naturally adjust focus for different lighting conditions. While strain can cause temporary fatigue, myopia (nearsightedness), and other refractive errors are primarily genetic or developmental. The myth may conflate temporary discomfort with lasting damage, or it may have been used to encourage children to turn on lights for safety reasons.