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What causes Myopia?

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Author: Jason Higginbotham
BSc (Hons) MCOptom Prof Cert Glau Prof Cert Med Ret Prof Cert LV FBDO MBCLA

What Causes Myopia

So...exactly what causes myopia?

Now you understand better what myopia is and the types of myopia, let's look at some of the causes of myopia. Many studies have been conducted to uncover what causes myopia and the current thinking suggests perhaps unsurprisingly that there are many factors that lead to myopia developing. The process itself can be part of the normal development of the eye, but this process seems to continue beyond the point it should stop.

Most modern theories of myopia revolve around the peripheral hyperopic defocus blur model, but there are also other causes and increased risk factors, such as genetic predisposition, lifestyle and more.

We'll take a look at them here:

Digital devices and myopia

The rise in myopia is influenced by environmental and genetic factors, with recent increases linked to lifestyle changes. One emerging concern is the impact of smartphones and digital devices on children's eye health.


Smartphones, tablets and computers are widely used at a very early age in both home and school environments. Smartphones, in particular, have become a ubiquitous part of modern life. Children are the fastest growing population of smartphone users, which is reflected in recent usage statistics internationally.

Emerging research indicates that the use of smartphones, characterized by smaller screens and closer working distances, may pose a heightened risk of myopia, especially among younger individuals. This shift toward excessive smartphone usage, coupled with reduced outdoor time and increased screen exposure, could exacerbate the myopia epidemic.

The repercussions of rising myopia rates extend across various domains, impacting society, the economy, education, and overall quality of life.

Moreover, there is a notable lack of parental understanding regarding myopia and its causes. This underscores the urgent need for public awareness and educational initiatives. Effectively controlling myopia progression in children will necessitate informed parental involvement.




Myopia typically develops in childhood as a result of the eye growing too long from front to back which is referred to as the axial length of the eye

What can you do to protect your child's vision health when using digital devices?

In myopia, the process of elongation of the eyeball continues beyond the point of emmetropisation. In essence, the eyeball gets too long and the child becomes short-sighted. The measurement of the length of the eyeball is called the axial length.


There are several theories as to why this happens. Ultimately, where there is a lot of close work taking place, a mechanism in the eye detects that the image in the periphery is out of focus and is 'hyperopic', essentially trying to focus behind the retina (in other words the peripheral eye is too short). This triggers another mechanism that leads to the eyeball becoming longer to help bring these peripheral images into focus on the retina.

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The problem is, continued close work leads to the same problem happening and the eye ‘tries’ to elongate once again. This cycle of progressive eyeball elongation is what leads to the axial length of the eye to continue increasing, resulting in higher and higher levels of myopia.

TL;DR Key Points
  • Myopia develops due to multiple factors and is not fully understood.

  • The peripheral hyperopic defocus blur model is a leading theory in myopia's explanation.

  • Hyperopia (longsightedness) is common in young children, but the eye elongates to achieve clear focus (Emmetropisation).

  • In myopia, the elongation of the eyeball continues excessively, causing nearsightedness.

  • Excessive close work, little outdoor time, genetics, and digital device use increase myopia risk.

  • Research on myopia is rapidly advancing, providing more knowledge for prevention.


The main causes of myopia


Too much close work - homework, reading, and writing 


Too little time spent outdoors and exposure to sunlight


Genetics - parents having myopia and/or ethnic pre-disposition (oriental/Asian descent


Prolonged use of tablets and smartphones

There are many other potential causes and risk factors, but their effects are currently considered less significant than those above.

Research is taking place at a phenomenal rate and more knowledge and information around myopia and its causes are developing rapidly.

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Types of

There are two main types...

Image by CDC

Myopia Symptoms

What to look out for

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