The Claim
The rapid increase in myopia prevalence over decades is caused by environmental factors rather than genetic changes.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
The rise in nearsightedness over the past several decades is due to changes in the environment, not changes in human genes.
See the scientific wording
The rapid increase in myopia prevalence over decades is caused by environmental factors, not genetic changes.
When children spend too much time indoors under dim light and focus on close objects, their eyes receive less bright sunlight and more sustained near-vision signals. This reduces dopamine release in the retina, which normally keeps the eye from growing too long. At the same time, the ciliary muscle stays contracted during near work, pulling on the back of the eye with constant tension. This pull activates signals that break down the eye's outer wall, making it stretch backward. The eye becomes longer than it should be, so light focuses in front of the retina instead of on it, causing nearsightedness.
What the research says
5 studiesStudy: Smartwatch Measures of Outdoor Exposure and Myopia in Children
Kids who spend more time outside in bright sunlight have less worsening of their nearsightedness each year, which means being indoors too much is likely making eyes worse—not our genes changing. This helps explain why more kids are nearsighted now than 50 years ago.
Even though the study couldn't prove it for sure, it found hints that kids who spend less time outside or whose moms had more inflammation during pregnancy are more likely to become nearsighted—suggesting the environment, not genes, is probably behind the recent rise in myopia.
Kids became nearsighted not just because of their genes, but mainly because they spent too much time doing close-up work like homework and using screens. Their genes made them more likely to get nearsighted only if they also did a lot of close-up work.
People aren't becoming nearsighted because their genes changed — they're becoming nearsighted because spending more time in school makes their existing genetic risk for nearsightedness worse.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 5 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.