Reading in dim light ruins eyesight
Reading in low light causes temporary eye strain but does not cause permanent damage to the eyes or lead to nearsightedness. This well-known household warning has no basis in ophthalmological evidence.
What we know
The idea that reading in dim light damages the eyes has been told to generations of children. In practice, poor lighting makes the eyes work harder to focus, which can lead to eye strain, temporary fatigue, headaches, or difficulty focusing, but these effects are entirely reversible when the eyes are rested.
The University of Utah Health, Warby Parker's clinical team, and multiple ophthalmology sources confirm that no anatomical or physiological damage to the eye results from reading in low light. The claim that it causes nearsightedness is also unsupported. Nearsightedness (myopia) is influenced by genetics and, to some degree, by extended periods of near-work generally, but this is not the same as damage from dim lighting.
When reading in low light, pupils dilate to admit more light, which can reduce depth of field and make text appear less sharp. This temporary optical effect may make reading uncomfortable, but it does not harm the retina, cornea, lens, or other ocular structures. The British Medical Journal has noted that while dim light may lead to eye strain, it does not result in permanent damage.
Good lighting when reading is advisable for comfort and to reduce fatigue, but the notion that inadequate light actively injures the eyes is a persistent but unfounded belief.
Common claims
- Reading in the dark causes permanent nearsightednessNot supported by evidence
- Dim-light reading strains and scars the retinaFalse - strain is temporary
- Children who read under covers ruin their visionNo lasting damage demonstrated
- Eye doctors warn against dim-light reading for eye healthOnly recommended for comfort, not eye safety