Does reading in dim light harm your eyes?

What the evidence says

No, reading in dim light will not damage your eyes or cause any eye disease. This has been checked by eye researchers for decades, and there is no proof that using your eyes in low light hurts them in any lasting way.

What can happen is that your eyes feel tired, dry, or strained after reading in poor light for a while. This is called eye strain, and it is uncomfortable but temporary. It goes away once you rest your eyes or turn on a brighter light. It is not a sign of injury.

Older health reviews looked specifically at whether working or reading in low light causes conditions like glaucoma or cataracts, and found no evidence that it does. Eye strain itself is described as more about tired eye muscles and psychological discomfort than actual harm to the eye.

There is a separate and newer area of research looking at whether children who read a lot in dim light are more likely to develop myopia, where distance objects look blurry. A couple of studies in children found a statistical link between dim light reading and myopia, but these were observational studies. This means they show a pattern, not proof that dim light itself causes the problem, since other habits like doing a lot of close-up work could explain the link.

Overall, if reading in dim light makes your eyes feel uncomfortable, it is fine to turn on a light for comfort, but doing so is not medically necessary to protect your eyesight.