Lifestyle Factors Associated with Myopia in Schoolchildren

While for many, myopia is an optically corrected inconvenience (1),  for an ever-increasing minority, myopia is a factor leading to more severe vision disorders and visual impairment in mid to later life (2). Understanding myopia levels helps explain why even a modest refractive error in childhood can carry significant long-term risk if progression goes unmanaged. Myopia is a recognised growing health issue in East Asia, where large-scale measurement and monitoring first began in the 1980s, with a very high prevalence (80%–90%) in school leavers (3). The global myopia prevalence was estimated at two billion in 2010 and predicted to rise to five billion (half the projected world’s population) by 2050 (4).

What the Ireland Eye Study Found

The primary aim of the Ireland Eye Study was to report myopia prevalence in schoolchildren in Ireland. The study involved 1,626 schoolchildren from a mix of 37 urban/rural schools and schools in socioeconomically advantaged and disadvantaged areas throughout Ireland. All children had their eyes examined during the school day, and parents/guardians completed detailed questionnaires on diet and lifestyle. Sedentary lifestyle, obesity, increased screentime and reduced daylight exposure, in addition to family history, were associated with short-sightedness in these schoolchildren. Preventing and monitoring myopia can be facilitated through optical practice management software and  eyecare software, which provides practitioners with tools to track patient progress and develop personalised treatment plans.

Key Lifestyle Risk Factors for Myopia in Schoolchildren

• Screentime: Children using screens for more than three hours per day were almost four times more likely to be short-sighted than those spending less than one hour on screens daily. The relationship between smartphone usage and myopia may be due to several factors. The high accommodative demand associated with using smartphones at short working distances (5), cumulative blue light exposure (6), coupled with dim lighting resulting in dilated pupils and the resulting increased peripheral image defocus (7), plus the reduced time outdoors (8), may lead to increased risk of myopia onset or progression in susceptible children. 

• Obesity: Clinically obese children were close to three times more likely to be short-sighted than healthy-weight children. The cause is uncertain. What is known is that obesity is associated with reduced brain plasticity (9), increased metabolic disorders (10), diabetic retinopathy and peripheral artery disease where the tiny blood vessels supplying the eyes may be compromised (11). Further research is needed to unravel the relationship between BMI and myopia.

• No physical activity: Children with sedentary lifestyles were almost three times more likely to be short-sighted than children involved in regular physical activities. Consequently, longitudinal research on whether engaging in after-school physical activities or not engaging in screen-based activities to prevent myopia progression is crucial.

“Sedentary lifestyle, obesity, increased screentime and reduced daylight exposure, in addition to family history, were associated with short-sightedness in these schoolchildren.”

How to Reduce Myopia Risk Factors in Schoolchildren

• Outdoor time: Children who spent less than one hour outdoors per day were five times more likely to be short-sighted than those spending more than four hours outdoors daily during summer. Whether increasing myopia prevalence is to do with less outdoor time or due to activities pursued indoors is a matter for speculation (12). Recent research demonstrated time outdoors >2.5 hours per day during daylight may postpone the onset of myopia and slow the myopic shift in refractive error (13); however, results regarding the effects of daylight exposure on myopia progression are equivocal. The mechanisms underpinning daylight exposure’s protective effect against myopia are unclear; increased depth of focus plus low accommodative demand associated with time spent outdoors has been proposed as possible biological mechanisms (14). Whether this is entirely due to the flat dioptric topography of the visual field outdoors (15), or due to increased light levels outdoors is inconclusive. The close link between circadian rhythms and eye growth and decreased sleep quality with later bedtimes in children with high myopia (16) further reinforces the part light exposure plays in refractive error development in children. Therefore, circadian timing and school hours may be essential factors to consider when addressing myopia control at a public health level.

• Breastfeeding for the first three months of life appeared to have a protective effect against short-sightedness, with bottle-fed babies twice as likely to be short-sighted. Breastfeeding during infancy provides babies with polyunsaturated fatty acids, essential vitamins and bioactive components necessary for brain and retinal growth and maturation in infants (17). Long-chain polyunsaturated fatty acids are essential throughout the retina to support retinal structure and function, influencing visual development and eye growth (18).

1. The 20-20-20 rule: Don’t forget to practice the 20-20-20 rule. Every 20 minutes, look at objects that are 20 feet away for 20 seconds during any near-vision activity like reading, writing, texting, playing games, etc.). The Korean Myopia Society recommends that children take a 20-second break to look at something at least 20 feet (6 metres) away after every 20 minutes of near work. Prolonged near work and short working distances have been associated with a higher risk of developing myopia, with near-work distances of less than 30 cm linked to a 2.5-fold higher risk of myopia onset and continuous near work lasting more than 30 minutes associated with a 1.5-fold higher risk (19).

Is Childhood Myopia Genetic or Caused by Lifestyle?

The cause of childhood myopia is mostly hereditary. If one or more of the parents have myopia, the child is likely to develop it early in life. But lifestyle factors, like the amount of time the child spends indoors, in front of a screen with minimal to no physical activity, may also affect whether they develop myopia and how quickly it can progress.  

That’s why early treatment, together with spending more time outdoors with more physical activity, can slow down the progression of myopia.

What This Means for Parents and Practitioners

One clear message today is the importance of daily outdoor physical activities and managing children’s screentime as a necessary part of children’s eye health. More research examining the broader consequences of today’s ubiquitous media environment and, in particular, the effect this intense digital immersion may have on children’s health and vision needs to be addressed as part of the broader public health education program.

Whilst many of the health benefits associated with increased physical activity, reduced screentime, and increased outdoor time may not manifest themselves until adulthood, the benefits at that time will be material, with significant benefits for not only the individual but also the community in terms of independence and quality of life. 

Tracking children’s eyesight over time is easier with the right tools in place. Contact us to learn how Acuitas 3 helps optometry practices track paediatric patients’ eye health.

References:  

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2. Sankaridurg P, Tahhan N, Kandel H, et al. IMI Impact of Myopia. Invest Ophthalmol Vis Sci. 2021;62(5):2-2. doi:10.1167/IOVS.62.5.2
3. Seet B, Wong TY, Tan DTH, et al. Myopia in Singapore : taking a public health approach. 2001:521-526
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7. Smith EL, Hung L-F, Huang J. Relative peripheral hyperopic defocus alters central refractive development in infant monkeys. Vision Res. 2009;49(19):2386-2392. doi:10.1016/j.visres.2009.07.011
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15. French AN, Ashby RS, Morgan IG, Rose KA. Time outdoors and the prevention of myopia. Exp Eye Res. 2013;114:58-68. doi:10.1016/j.exer.2013.04.018
16. Nickla DL. Ocular diurnal rhythms and eye growth regulation: Where we are 50 years after Lauber. Exp Eye Res. 2013;114:25-34. doi:10.1016/j.exer.2012.12.013
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18. Gorusupudi A, Liu A, Hageman GS, Bernstein PS. Associations of human retinal very long-chain polyunsaturated fatty acids with dietary lipid biomarkers. J Lipid Res. 2016;57(3):499-508. doi:https://doi.org/10.1194/jlr.P065540
19. Lee YH, Sung JY, Shin SY, Suh YW, Kim US, Kim H, Park KA, Kim SJ, Kim M, Shin HJ, Lee KW, Lee HJ, Han SY, Han J, Hong EH, Baek SH, Paik HJ; Korean Myopia Management Consensus Task Force. Myopia Management Consensus Statement in South Korean Children 2025 by the Korean Myopia Society for the Korean Association for Pediatric Ophthalmology and Strabismus. Korean J Ophthalmol. 2026 Apr;40(2):185-205. doi: 10.3341/kjo.2025.0179. Epub 2026 Feb 4. PMID: 41633654; PMCID: PMC13078937.