The increasing prevalence of nearsightedness, or myopia, is a growing global health concern, with rates climbing rapidly in recent decades. While increased screen time has long been suspected as a primary driver, new research suggests the issue may be more closely linked to how we employ our eyes indoors, particularly the sustained close-up focus in low-light environments. This finding challenges previous assumptions and opens new avenues for understanding and potentially mitigating the rise in myopia cases worldwide.
Myopia, which blurs distant vision, is reaching near-epidemic levels, affecting nearly half of young adults in Europe and the United States and approaching 90% in parts of East Asia. While genetic predisposition plays a role, the speed at which myopia is increasing suggests environmental factors are significantly contributing to the problem. Researchers are now focusing on the amount of light reaching the retina during prolonged periods of near work, such as reading or using digital devices indoors.
The Role of Light and Indoor Focus
Scientists at the State University of New York (SUNY) College of Optometry have proposed that prolonged close-up focus in low-light conditions may limit the amount of light reaching the retina, potentially triggering or accelerating the development of myopia. Professor Jose-Manuel Alonso, the senior author of the study, explained that “Our findings suggest that a common underlying factor may be how much light reaches the retina during sustained near work – particularly indoors.” This suggests that simply reducing screen time may not be enough to curb the rise in myopia; the way we use our eyes indoors is crucial.
The research builds on existing knowledge that visual deprivation or the use of negative lenses can induce myopia in animal models. Scientists believe that different neuronal mechanisms are involved in these processes, but a unifying neuronal mechanism may explain both the induction and control of myopia. Opticians currently employ a range of approaches to manage myopia progression, and this new research aims to provide a more comprehensive understanding of the underlying biological processes.
Global Trends and Pandemic Impact
The global increase in myopia is not uniform. A global analysis published in the British Journal of Ophthalmology revealed that short-sightedness tripled between 1990 and 2023, reaching 36% globally. The highest rates are observed in Asia, with 85% of children in Japan and 73% in South Korea experiencing myopia, while rates in China and Russia exceed 40%. Conversely, Paraguay and Uganda have some of the lowest levels, at around 1%, with the UK, Ireland, and the US reporting rates of approximately 15%.
The study also indicated a “particularly notable” increase in myopia following the COVID-19 pandemic, potentially linked to increased screen time and reduced outdoor activity during lockdowns. This observation supports the idea that environmental factors, specifically time spent outdoors, play a significant role in eye health. Myopia typically begins during primary school years and tends to worsen until the eye stops growing, around age 20.
Cultural and Educational Factors
Beyond light exposure, cultural and educational practices also appear to influence myopia rates. The study highlighted that children in East Asian countries often begin formal education at a very young age, sometimes as early as two years old, leading to more prolonged periods of close-up work. In contrast, children in African countries, where schooling typically starts between six and eight years old, have significantly lower rates of myopia – approximately seven times lower than those in Asia.
This suggests that the age at which children begin intensive near work, combined with the amount of time spent indoors, may be critical factors in the development of myopia. While genetics contribute to susceptibility, these environmental influences appear to be driving the rapid increase in cases observed over recent generations.
As the number of short-sighted individuals continues to rise – with projections estimating that almost 3.4 billion people will be affected by 2030 – understanding the complex interplay of factors contributing to myopia is crucial for developing effective prevention and management strategies. Further research is needed to determine the optimal levels of light exposure and near work to promote healthy vision development.
What comes next will likely involve a deeper dive into the specific wavelengths of light that are most beneficial for retinal health, as well as the development of targeted interventions to encourage more outdoor activity and optimize indoor lighting conditions. Share your thoughts on this evolving understanding of myopia in the comments below.
