The increasing prevalence of nearsightedness, or myopia, has been linked to the amount of time individuals spend engaging with digital screens. A recent evidence review published in JAMA Network Open highlights that each additional hour spent squinting at a smartphone or staring at a screen elevates the risk of developing myopia by 21%.
The study, led by Young Kook Kim, an associate professor of ophthalmology at Seoul National University College of Medicine, reveals that the risk of myopia increases significantly with 1 to 4 hours of screen time and continues to rise gradually beyond that. People who spend four or more hours on screens daily are at double the risk of becoming nearsighted.
Researchers suggest a “potential safety threshold” of less than 1 hour of screen exposure per day. Exceeding this threshold up to 4 hours significantly increases the odds of developing nearsightedness. By 2050, it is projected that nearly half of the global population will be nearsighted, as detailed in the background notes of the study.
Nearsightedness occurs when close-up objects are clear, but distant objects appear blurry. According to the American Academy of Ophthalmology, this condition can make it difficult for individuals to perform tasks such as driving without corrective lenses.
The anticipated rise in myopia cases is largely attributed to environmental factors common in urban areas. These include increased near-vision activities and reduced outdoor time. The advent of smart devices has introduced new forms of near-work activity, compounding the problem.
As children begin using smart devices at younger ages and spend more time on digital screens, understanding the association between screen time and myopia becomes increasingly urgent. To address this, researchers analyzed data from 45 studies involving over 335,000 participants.
The analysis demonstrated a significant dose-response association, meaning the more time spent with screens, the higher the risk of nearsightedness. This risk is independent of other near-vision activities like reading or writing.
Researchers emphasize that reducing screen time alone may not suffice in preventing myopia. Instead, they recommend minimizing overall near-work activities while promoting more outdoor time as a more effective strategy to mitigate myopia risk.
