Cutting back on screen time for the sake of myopia management

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In an increasingly digital world, the rise of myopia has become a significant concern. Although it is easy to assume there is a direct connection between screen time and the myopia epidemic, the prevalence of myopia has been on the rise long before the increased use of screen time in children. In the early 2000s, the prevalence of myopia was almost double that in the 1970s.¹ Despite this observation, myopia development is multifactorial, thus the relationship between screen time and myopia must be explored.

The rise of screen time

Modern society is inundated with screens, and almost every adult has a smartphone, desktop, laptop, tablet, and other digital devices. Adults now spend approximately 28.5 hours on recreational screen time,² outside of work or school, which translates to more than 4 hours per day.

Screens are also not limited to adults. Children are being introduced to screens at younger and younger ages, with almost half being introduced to screens before the age of 1.³ The American Academy of Pediatrics discourages the use of screen media for children younger than 18 months and limiting to 1 hour in children between 2 and 5 years old.⁴ These recommendations are based on research that has shown links between screen media usage and obesity from a sedentary lifestyle, shorter sleep duration, cognitive and language developmental delays, and social and emotional issues.⁴

In this post–COVID-19 era, the move toward more online education, video conferencing, and the use of devices in the classroom has further proven that digital ways of communication are here to stay. Technology has generally changed our lives for the better, but in this case, children are now spending more than 2 hours per day on digital devices, which could impact their quality of vision.⁵

This impact that screen time has on eye health is further manifested in systemic health. Increased screen time has been associated with headaches and poor sleep quality.^6,7 From an ocular health perspective, blink rate is more infrequent with digital device use,⁸ which may lead to digital eye strain and dry eye syndrome.⁹ Therefore, limiting screen time can mitigate these deleterious effects.

The relationship between screen time and myopia

Generally, there are inconclusive results regarding the association between digital device use and myopia. However, one study observed an increase in myopic refraction by 0.28 to 0.33 D for every hour spent on digital devices.¹⁰ Children with myopia also have prolonged screen time compared with children who don’t have myopia.¹¹

In a 2019 systematic review on the association between digital screen time and myopia, Lanca and Saw found no definite relationship.¹² They included 15 studies, with 6 of 11 showing computer use was associated with myopia prevalence and only 1 of 4 showing a relationship between computer/video game use and myopia progression. The other 5 and 3 studies, respectively, demonstrated no relationship with screen use. Their meta-analyses of 5 studies concluded that screen time was not significantly associated with the prevalence or incidence of myopia.

A 2021 meta-analysis of 11 studies found that smart device use, both alone or in combination with computer use, was significantly associated with myopia.¹³ However, the authors point out that methodological differences exist among the included studies, and the association is not necessarily causal in nature. Also, studies do not always separate smart device use from other near work tasks. The effect of near work on myopia has long been studied, and screen time may just serve as a correlate for near work. However, digital devices differ from books or other printed material in terms of luminance, contrast, screen flicker, and other parameters that should be considered in future research.¹⁴

Managing screen time

Although screen time for entertainment purposes, such as television, gaming, and web browsing, can be limited, parents do not necessarily have control over the use of screens when it comes to schooling. With more online education, children spend more time using digital devices and less time outdoors. In China, the Ministry of Education implemented guidelines that included no more than 30% of teaching time with electronics, less than 20 minutes per day on electronic homework, and no phones or tablets in the classroom.¹²

In today’s modern society, it is unrealistic to prohibit screen time altogether, so eye care providers should emphasize the importance of moderation. Because digital device use at home can be monitored, providers can educate patients on screen time use and potential behavioral modifications to implement at home.

Parents also ask about screen filters and blue light–blocking glasses. Blue light can be found in outdoor environments and in LED lights and screens. A recent review showed that there was no evidence of any harmful effects of blue light on eye health, but long-term cumulative exposure is still unknown.¹⁵ For this reason, the authors recommended avoiding LED lights emitting cold white light with a high level of blue light, specifically in areas that children frequent. Blue light–blocking spectacles were not supported by the literature regarding their efficacy in protecting against myopia progression or ocular disease.

Lifestyle factors and myopia prevention

As myopia continues to be a growing public health concern, eye care providers must make education on ocular health a priority when serving pediatric patients. Understanding the use and role of digital devices in the lives of children should be a collaborative effort among health care professionals and educators. Eye care providers must educate children and families about the long-term risks of myopia and digital device use.

There are 2 behavioral modifications that are often recommended to delay the onset of myopia. The first is increased time spent outdoors. Although outdoor time has a protective effect on the incidence of myopia, there is no relationship with myopia progression.¹⁶ Providers should recommend at least 2 hours per day or 10 hours per week of outdoor time.

The second behavioral modification is decreasing near work intensity. Myopia onset can be delayed by increasing the near working distance to greater than 30 cm and increasing the number of breaks during near work, thereby shortening the amount of time on continuous reading.¹⁷

Major technology companies, such as Apple, have acknowledged the role of these lifestyle factors. Their latest software incorporates a feature where the device will display a warning when the iPhone or iPad is held closer than 12 inches for too long.¹⁸ The Apple Watch also has a feature to track the time spent outdoors in daylight.¹⁹

Conclusion

Ultimately, the rise in myopia preceded the rise in digital device use and current meta-analyses show that there is no definite relationship between the 2. Studies have mixed results, and those that find an association may not be causal in nature. Likewise, screen time and digital device use may be a conduit for increased near work. Despite the lack of concrete conclusions on the relationship between digital devices and myopia, there is sufficient evidence of the harmful effects of increased screen time on systemic and ocular health. Eye care providers should educate and discuss with patients and parents about managing screen time use.

References:

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19. See time spent in daylight. Apple. Accessed June 9, 2024. https://support.apple.com/guide/watch/see-time-in-daylight-apd3ab22534c/10.0/watchos/10.0