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What Are the Risks of High Myopia?

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A young woman wearing glasses due to myopia

High myopia is a more severe form of nearsightedness. If your child is struggling to read the board during school or squinting to focus on the TV at home, causing them headaches and eye strain, they could be experiencing symptoms of high myopia. There are serious risks associated with high myopia to consider.

Your eye doctor can treat your child’s high myopia if diagnosed early. However, if left untreated, high myopia can lead to an increased risk of eye disease later on in life. It’s crucial to diagnose high myopia early and get your child the help they need.

Diagnosing High Myopia

Myopia is caused when light entering the eye lands in front of the retina instead of directly on it. When light passes through a myopic cornea, it refracts differently than if it were to pass through a healthy one. This refractive error is usually a result of an elongated, misshapen cornea. 

When your doctor provides a prescription for eyeglasses, they give a measurement in a unit called dioptres. A positive dioptres measurement means hyperopia or farsightedness. A negative dioptres measurement means myopia, otherwise known as nearsightedness. 

A mild myopia prescription falls between -0.25 and -3.00 dioptres. A prescription between -5.00 and -6.00 indicates high myopia. 


High myopia presents the same symptoms as more mild forms of myopia; however, they’re more severe. These symptoms can include:

  • Blurry vision at a distance
  • Frequent squinting
  • Severe headaches
  • Eyestrain

Most of the time, high myopia is diagnosed before the age of 13. Diagnosing high myopia early is essential to reducing the risk of developing more severe conditions. 

Risk Factors

High myopia is generally understood to be a genetic eye condition. Other risk factors include a child’s vision habits, such as extended screen time where they focus too much at a close distance. 

A boy holding a pair of prescription glasses out in front of him

High Myopia Risks

If high myopia isn’t treated correctly or early enough, children may be at greater risk of developing more severe eye conditions later on in life. 


Glaucoma is one of the leading causes of blindness among Canadians. Glaucoma is caused by increased pressure in the back of the eye, which places stress on the optic nerve. There are a few different types of glaucoma. High myopia generally increases a person’s risk of developing open-angle glaucoma—the most common form of the disease.

People with high myopia are 50% more likely to develop glaucoma than those with mild myopia.


Cataracts occur when the lens of your eye becomes cloudy, which obscures your central vision and makes objects appear blurry. Cataracts are caused by a buildup of protein on the lens, which usually is transparent and flexible to help focus light on the retina. As protein builds up, the lens thickens and becomes rigid. In severe cases, cataracts can lead to blindness.

Severe cataracts are usually treated with cataract surgery. People with high myopia are 17% more likely to require cataract surgery than those with mild myopia.

Retinal Detachment

The retina sits on the back wall of your eye and sends light information through the optic nerve to the brain. Retinal detachment occurs when the retina peels away from the back wall. When the retina detaches from the wall, it can’t send light information to the brain. In severe cases, retinal detachment can lead to permanent vision loss. 

People with high myopia are 5–6 times more likely to experience retinal detachment than those with mild myopia. 

Myopia Control 

Most of the time, high myopia is diagnosed before the age of 13. Children need to have their eyes checked regularly to monitor for myopia and other eye conditions and determine if strategies like myopia control are an option.

Children are constantly growing, whether it’s their height, brains, muscles, or other organs—including their eyes. Children’s eyes are more flexible than adults. Since an irregularly-shaped cornea causes myopia, myopia control can introduce strategies to reshape and reduce strain on the eye to reduce your child’s risk of developing high myopia. 

Total Focus Optometry offers speciality contact lenses and specialty glasses lenses to help manage your child’s myopia. Starting myopia control early is vital to reducing your child’s risk of developing high myopia or other eye diseases. Book an appointment so we can test your child’s eyes and recommend myopia control treatments if they’re needed.

Written by Dr. Craig M

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