Even as the COVID-19 pandemic has increased children's digital screen time, it may also pose potential risks to their vision and overall health.

The pandemic caused an unprecedented move to remote learning. With many countries closing their schools, students were left to rely on digital devices to continue with their education. As a result, many children are at risk of having eye strain, unstable binocular vision (using both eyes adequately to create a single visual image), uncorrected refractive error and dry eyes, said researchers at Anglia Ruskin University (ARU) in the UK.

They conducted a review of studies carried out worldwide during the pandemic, and the findings published in the Journal of School Health show a consistent picture of increased digital screen time for children and adolescents. In Canada, 89 per cent of parents admitted their children were exceeding the two-hour daily guidelines set by the country's health authorities.

While in Germany, screen time increased by approximately an hour a day, in Chile, a study found screen time among toddlers and pre-school children had almost doubled to more than three hours per day, and in Tunisia, researchers reported an increase of 111 per cent in total screen time for children aged 5-12.

The review also reported that children and adolescents often use several devices at once, for example, to browse social media on their phones while watching content on another device. Switching between devices increases the strain on the eye by 22 per cent, as this entails switching distances between different devices, forcing the eyes to adjust, the researchers said.

"It is really important to be aware of the potential risks to children's short and long-term eye and general health. It is essential that devices are used appropriately and that activities away from digital devices are encouraged, such as playing outdoors," said lead author Professor Shahina Pardhan, Director of the Vision and Eye Research Unit at ARU.

Further, increased screen time can also lead to neck and shoulder strain. It also raises the amount of time spent sedentary and is associated with overeating, potentially resulting in health issues such as obesity. Pardhan noted that schools should make sure time spent on digital devices is maximised for learning and less for other activities.

Pardhan added that "governments should work with schools to help shape home-based learning guidelines that encourage creative learning away from devices, including promoting other types of activities and frequent screen breaks".