Understanding Your Child’s Myopia Risk in Canada

Myopia, also known as short-sightedness or nearsightedness, is becoming increasingly common among children worldwide, including in Canada. Myopia causes distant objects, such as those across a room or outside a window, to appear blurry. Children and teens with myopia need glasses or contact lenses to see clearly. Once it is first diagnosed in children, it tends to progress or worsen every few to several months, requiring stronger and stronger glasses to correct it. As a parent, understanding the factors that contribute to your child’s risk of developing myopia can help you take proactive steps to protect their vision. This article explores the key risk factors, early warning signs, and what you can do to slow down its progression.

The Growing Concern: Myopia in Canadian Children

A recent study found that myopia affects 6% of Canadian children aged 6 to 8 years, increasing to 29% in children aged 11 to 13 years. The increasing number of children affected by myopia highlights the need for early detection and management. More concerningly, about 35% of children with myopia in Canada remain uncorrected, which means having no glasses to give them clear vision, and can affect learning and development.¹ Early intervention and awareness campaigns are essential in ensuring children receive proper vision care, which can help minimize potential academic and social struggles due to blurry vision.

Who Is at Risk? Key Factors for Myopia Development

Researchers have identified several factors that can increase a child’s risk of developing myopia. One of the strongest predictors is family history. If one parent has myopia, the child is three times more likely to develop myopia themselves, and the risk doubles if both parents have myopia.² However, environmental factors also play a significant role.

A child’s visual environment greatly influences their likelihood of developing myopia. Limited outdoor time, particularly spending less than two hours per day outside, has been linked to a higher risk.³ Excessive near work, such as screen time, reading, or other close-up activities exceeding three hours daily (excluding school time), further increases the chances of developing myopia.⁴ Extended periods of focusing on close-up objects without breaks can strain the eyes and contribute to the excessive growth of the eyes (faster than expected when compared to normal childhood eye growth), which is the key factor in myopia development.

Certain binocular vision issues (how both sets of eye muscles work together) can increase the risk of developing myopia,⁵ and also make it harder for the eyes to focus accurately up-close.⁶ Addressing these vision issues with early detection and proper treatment, with glasses or evidence-based eye exercises, may help reduce the likelihood of myopia progression in some children.

The most significant predictor of a child developing myopia is their current prescription or level of vision. Younger children are meant to have a certain amount of hyperopia (long-sightedness or farsightedness), and if they don’t have that amount, they are likely to develop myopia by their teenage years.⁷ Routine eye exams can help identify these early signs and allow optometrists to advise parents on strategies that reduce the risk of myopia or delay it’s occurrence.

Understanding Myopia Progression

Once a child becomes myopic, their vision tends to worsen each year. Several factors influence how quickly myopia progresses. The younger the child is when myopia is diagnosed, the faster their vision deteriorates.⁸ Children with two myopic parents typically experience faster progression or worsening.^9,10 Additionally, prolonged screen time and reading or looking at screens closer than 20 cm from the eyes can contribute to rapid deterioration.¹¹ Studies have shown that Asian ethnicity is associated with a higher rate of progression.^8,12 Some binocular vision (eye muscle coordination) issues can also be linked to faster myopia progression.¹³

Understanding that myopia progresses at different rates for each child is important. Regular eye exams can track changes, determine how effective treatments are, and help determine if additional myopia control measures are needed.

How to Reduce Your Child’s Myopia Risk

While some risk factors (such as genetics) cannot be changed, there are many effective ways to reduce the risks of myopia. Increasing outdoor time is one of the simplest yet most effective strategies. Studies suggest that at least two hours of outdoor activity per day can significantly reduce the risk of developing myopia.³ Exposure to natural light and engaging in activities that require distance vision can help lead to normal eye growth in childhood (instead of excessive eye growth found in myopia) and maintain better overall eye health.

Limiting screen time and close-up vision tasks are equally important. Encouraging children to follow the 20-20-20 rule—taking a 20-second break to look at something 20 feet (6 metres) away every 20 minutes—can help reduce eye strain. Keeping reading and screen distances at least 30 cm away from the eyes and avoiding prolonged study sessions without breaks also contributes to healthier vision habits. Parents can also promote balanced screen usage by setting daily limits – such as a maximum of two hours of leisure screen time per day, outside of schoolwork – and encouraging a mix of indoor and outdoor activities.

Regular eye check-ups are crucial for monitoring eye health. The Canadian Association of Optometrists recommends that children have their first eye exam at six months, again at age three, and annually after starting school.¹⁴ Close monitoring is particularly important for children under ten, as this is when myopia tends to emerge and then progress most rapidly. Consistent eye exams allow for early intervention, enabling optometrists to recommend treatments such as myopia control glasses or contact lenses or other lifestyle and visual habit changes to slow myopia progression.

For children already diagnosed with myopia, several myopia control options can help slow progression. Consulting with an optometrist about the best course of action for a child’s individual needs can make a significant difference in long-term vision outcomes. You can learn more about the different treatment options for myopia control available here in Canada in the article Treatment Options for Myopia in Canada: An Overview, or for a comprehensive guide and research evidence you can read Which is the best option for myopia control? on MyKidsVision.org.

Protecting Your Child’s Vision and Eye Health

Understanding your child’s risk factors for myopia allows you to take early action. Encouraging outdoor time, managing screen use, and scheduling regular eye exams are practical strategies that can help protect their vision. If your child has already developed myopia, consulting an optometrist about available treatment options can help slow down myopia progression. Taking an active role in managing your child’s visual health can improve their quality of life now and reduce the long-term impacts of myopia on their vision and eye health.

References

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2. Jones LA, Sinnott LT, Mutti DO, Mitchell GL, Moeschberger ML, Zadnik K. Parental History of Myopia, Sports and Outdoor Activities, and Future Myopia. Invest Ophthalmol Vis Sci. 2007;48:3524-3532.
3. Xiong S, Sankaridurg P, Naduvilath T, Zang J, Zou H, Zhu J, Lv M, He X, Xu X. Time spent in outdoor activities in relation to myopia prevention and control: a meta-analysis and systematic review. Acta Ophthalmol. 2017 Sep;95(6):551-566.
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5. Mutti DO, Jones LA, Moeschberger ML, Zadnik K. AC/A Ratio, Age, and Refractive Error in Children. Invest Ophthalmol Vis Sci. 2000;41:2469-2478.
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7. Zadnik K, Sinnott LT, Cotter SA, Jones-Jordan LA, Kleinstein RN, Manny RE, Twelker JD, Mutti DO, Collaborative Longitudinal Evaluation of E, Refractive Error Study G. Prediction of Juvenile-Onset Myopia. JAMA Ophthalmol. 2015;133:683-689. 
8. Donovan L, Sankaridurg P, Ho A, Naduvilath T, Smith ELI, Holden BA. Myopia progression rates in urban children wearing single-vision spectacles. Optom Vis Sci. 2012;89:27-32. 
9. Kurtz D, Hyman L, Gwiazda JE, Manny R, Dong LM, Wang Y, Scheiman M. Role of parental myopia in the progression of myopia and its interaction with treatment in COMET children. Invest Ophthalmol Vis Sci. 2007;48(2):562-570.
10. Loh KL, Lu Q, Tan D, Chia A. Risk factors for progressive myopia in the atropine therapy for myopia study. Am J Ophthalmol. 2015;159:945-949.
11. Huang PC, Hsiao YC, Tsai CY, Tsai DC, Chen CW, Hsu CC, Huang SC, Lin MH, Liou YM. Protective behaviours of near work and time outdoors in myopia prevalence and progression in myopic children: a 2-year prospective population study. Br J Ophthalmol. 2020 Jul;104(7):956-961. 
12. Hyman L, Gwiazda J, Hussein M, Norton TT, Wang Y, Marsh-Tootle W, Everett D. Relationship of age, sex, and ethnicity with myopia progression and axial elongation in the correction of myopia evaluation trial. Arch Ophthalmol. 2005;123(7):977-987.
13. Yang Z, Lan W, Ge J, Liu W, Chen X, Chen L, Yu M. The effectiveness of progressive addition lenses on the progression of myopia in Chinese children. Ophthal Physiol Opt. 2009;29:41-48. 
14. Canadian Association of Optometrists. Comprehensive eye examinations [Internet]. Ottawa (ON): Canadian Association of Optometrists; 2022 Mar. Available from: https://opto.ca/sites/default/files/resources/documents/cao_position_statement_comprehensive_eye_exams_final_feb_28_2017.pdf