"Reading in the dark will ruin your eyesight" is something almost everyone heard as a kid. But it isn't actually true.
■ Does Reading in Dim Light Affect Your Eyesight?
The brightness of your surroundings while reading a book doesn't have a major effect on eyesight. That feeling of your vision worsening comes from the muscles around your eyes tensing up and tiring out when you read in dim light.
■ The Real Risk Is Self-Lit Screens
That said, using a self-luminous electronic device — like a smartphone — instead of a book in the dark can actually harm your eyesight. Certain wavelengths emitted by electronic devices can damage retinal cells.
FAQ
Q. Does reading a book in dim light damage your eyesight?
A. Not significantly. Reading in low light causes the eye muscles to tense and tire, which feels like blurred vision, but it doesn't meaningfully harm eyesight itself.
Q. Is using a phone in the dark different from reading a book in the dark?
A. Yes. Self-luminous screens like smartphones emit wavelengths that can damage retinal cells, which is different from the eye strain caused by reading a printed book in dim light.
Q. What actually causes the eye strain felt when reading in the dark?
A. Tension and fatigue in the muscles around the eyes as they work harder to focus in low light, not permanent damage to eyesight.
