Causes of Myopia
Myopia, also referred to as short-sightedness, most commonly arises when the eyeball is elongated, resulting in blurred vision at a distance. Contributing factors include genetic predisposition, environmental influences, and prolonged near vision tasks such as excessive reading or screen time.
Genetics
Nature
The genetics of myopia involve many genes rather than a single “myopia gene.”
​​
-
Heritability is high—studies show that 50–80% of the variation in myopia risk is explained by genetic factors.
-
Polygenic nature: Hundreds of gene variants have been linked to eye growth, scleral structure, and visual signal pathways (e.g., those involved in extracellular matrix remodeling and retinal neurotransmission).
-
Gene–environment interaction: Genetic predisposition interacts strongly with lifestyle factors like near work, outdoor time, and education level.
-
Family history: Children with one or two myopic parents are significantly more likely to develop myopia, and it tends to appear earlier and progress faster.
Environment
Nature
Environmental causes of myopia mainly include:
-
Too much near work, like reading, using phones, or computers for long periods.
-
Not enough time spent outdoors in natural light, which helps protect the eyes.
-
Limited exposure to daylight can affect eye growth and increase myopia risk.
These factors can contribute to developing myopia or make it progress faster, especially in children.