Data from a study published in Clinical and Experimental Optometry has found that children with myopia use twice the amount of smartphone data each day as their non-myopic peers, adding weight to the argument that sustained levels of device usage from a young age increases the risk of myopia.

Results showed myopic refractive error was associated with increased smartphone data usage, with children who had normal levels of vision consuming an average of 614MB data daily and spending nearly four-and-a-half hours on the phone each day. In contrast, young myopes consumed an average of 1,131 MB data daily and spent nearly five hours on the phone daily.

The researchers, from Dublin Institute of Technology’s Centre for Eye Research Ireland (CERI) research arm, gave questionnaires on smartphone usage to 418 Irish children and students enrolled in primary, secondary, and university level schooling, then compared their refractive status. Data usage from the smartphones was then recorded over an extended period, along with the top three applications that consumed the most data and a self-reported estimate of time spent per day on the phone.

The students used an average of 873MB of data daily and about four hours of time spent on the phone each day, mostly spent using social media apps including Snapchat, Instagram and Facebook. Researchers found that myopes not only used more data and spent longer on their phones than non-myopes, but also were more likely to believe screen use could affect their eyes.


Other findings included 84% of myopes believing that digital technology could adversely affect their eyes compared to 68% of non-myopes. Both groups said they suffered from dry eyes (67%) and eyestrain (29%). A similar number of myopes and non-myopes believed digital screen use could cause myopia (31% and 25%, respectively).

‘The lifestyle habits of children and teenagers today have undeniably changed with advancements in technology and while the prevalence of myopia has been increasing for decades, the increased level of near visual stimulation from smartphones may pose an additional independent risk for myopia,’ said the study’s authors.

‘Smartphones differ from traditional reading in various aspects such as wavelength, distance from the eye, size, contrast, resolution, temporal properties and spectral composition, all of which merit investigation. Aside from this, children and adolescents now spend more time than ever using a smartphone that demands proximal attention, which may compete with other more protective activities such as time outdoors,’ concluded researchers.

Pandemic potential

In an American Optometric Association blog post, associate dean for research at Illinois College of Optometry Yi Pang, MD OD, noted that months of distance learning on handheld devices or computers due to pandemic lockdowns could compound the issue. In addition, Pang said prior research had already highlighted the trend for an increasing number of children spending more time on digital devices, in particular, longer times spent on near work and shorter working distances having the potential to increase myopia progression.

‘With the Covid-19 pandemic, the time on electronic devices dramatically increased in children because of remote learning and fewer opportunities for kids to do other activities. Based on the results, the risks for myopia development and progression may be higher in this pandemic situation,’ she said.

However, Pang warned the study only found an association with myopia and not a causation, which should be grounds for future studies. ‘Eye care practitioners should be aware of this issue and be ready to address parents’ and patients’ concerns,’ she said.