CAUSES OF MYOPIA
Myopia, commonly known as short-sightedness or nearsightedness, is a refractive error where distant objects appear blurry while close objects can be seen clearly.
Genetics
The genetics of myopia involve many genes rather than a single “myopia gene.”
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Heritability is high—studies show that 50–80% of the variation in myopia risk is explained by genetic factors.
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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).
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Gene–environment interaction: Genetic predisposition interacts strongly with lifestyle factors like near work, outdoor time, and education level.
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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
Environmental causes of myopia mainly include:
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Too much near work, like reading, using phones, or computers for long periods.
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Not enough time spent outdoors in natural light, which helps protect the eyes.
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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.
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Family History of Myopia: Children with one or both parents who are Myopic have a significantly higher risk of developing myopia.
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Increased Near Work: Spending long hours reading, using digital screens, or doing other close-up tasks can contribute to myopia progression.
Risk factors for Myopia
Limited Time Outdoors: Studies show that children who spend less time outdoors are at higher risk, likely due to lower exposure to natural light.
Early Onset: Myopia that develops at an early age often progresses more severely over time.
Ethnicity: Some ethnic groups, particularly individuals of East Asian descent, have higher rates of myopia.