Researchers at SUNY College of Optometry have proposed a new explanation for the worldwide spike in childhood nearsightedness, shifting blame from screens alone to something far more routine: spending long hours focused on close objects under dim indoor lighting. The hypothesis, published in February 2026, arrives as global myopia rates among young people have climbed from roughly 24% in the 1990s to 36% in recent years, with projections suggesting nearly 40% prevalence by 2050. If the theory holds, the fix may be simpler than many expected, and the evidence from large-scale trials in China already points in that direction.
Myopia Rates Are Rising Faster Than Genetics Can Explain
Genes have not changed fast enough to account for the speed of this increase. A meta-analysis of 276 epidemiological studies spanning 50 countries and approximately 5.41 million participants found that pooled myopia prevalence among children and adolescents jumped from about 24% in 1990-2000 to roughly 36% in 2020-2023. That same analysis projects prevalence will reach approximately 39.8% by 2050, translating to an estimated 740 million cases among people aged 5 to 19. The pace of that climb, roughly 12 percentage points in just over two decades, far outstrips what inherited risk factors could produce on their own and strongly implicates modern lifestyles.
Environmental factors are the obvious suspects, and for years the default explanation centered on “too much screen time.” But screens are only part of the picture. Children in East Asia, where myopia rates are highest, were developing nearsightedness at alarming rates well before smartphones became universal. What those children did share was a pattern of intensive near-focus study in indoor classrooms with relatively low ambient light. That overlap between close visual work and dim environments is exactly what the new SUNY hypothesis targets, suggesting that how and where children use their eyes may matter more than which specific device or medium they use.
A New Theory Points to Dim Light, Not Just Screens
The research from SUNY College of Optometry attempts to answer a question that has frustrated vision scientists for decades: why does near work indoors carry more myopia risk than near work outdoors? The proposed mechanism centers on how the retina processes light when a person focuses on a close object in low-light conditions. Under bright natural sunlight, the retina receives strong, even illumination that helps it accurately gauge focal distance and maintain stable eye growth. Indoors, where light levels can be 100 to 1,000 times lower, the retinal signals become less precise, and the eye may compensate by elongating, the structural change that defines myopia.
This distinction matters because it reframes the problem. If dim indoor lighting is the real amplifier, then simply telling families to “put down the phone” addresses only half the equation. A child reading a paper textbook for hours in a poorly lit classroom faces a similar risk profile to one scrolling on a tablet in a dark bedroom. The hypothesis, as summarized in a February 2026 report on indoor near work, does not yet have a dedicated clinical trial behind it. It draws on correlational trends and established optical science rather than a randomized experiment isolating indoor light levels. That gap is significant: until a controlled study tests the mechanism directly, the theory remains a well-reasoned but unproven framework. Still, it aligns neatly with a growing body of trial data showing that outdoor light exposure itself can slow myopia onset.
Outdoor Time Trials Show Measurable Protection
The strongest causal evidence comes from two cluster-randomized trials conducted in Chinese schools. In Guangzhou, researchers ran a three-year school-based trial from October 2010 to October 2013, adding one extra 40-minute outdoor class to each school day. Among children in the intervention group, the three-year cumulative incidence of myopia was 30.4%, compared with 39.5% in the control group. That 9.1 percentage-point gap emerged from a single, low-cost change to the daily schedule, with no special equipment or medication involved, and was accompanied by smaller average shifts in refractive error and eye length among children who spent more time outside.
A second trial in Shanghai, known as the STORM study, tested adding either 40 or 80 minutes per day of outdoor time and used objective light sensors to track both intensity and actual time spent outside versus inside. The study evaluated two-year cumulative incidence among children who were not yet myopic at baseline, along with changes in spherical equivalent and axial length, the key physical measurements of eye elongation. Together, these trials establish that more time in bright outdoor light can slow the onset of nearsightedness in children, even without reducing homework loads or screen use. No comparable randomized trials have been conducted in the United States or Europe, so the precise effect size in Western school settings remains uncertain, but the biological plausibility of light-driven protection is increasingly hard to ignore.
What Parents and Schools Can Do Now
The U.S. Centers for Disease Control and Prevention already recommends three practical steps to protect children’s vision: limiting recreational screen time, taking frequent breaks from near-vision tasks, and spending time outdoors each day. Those guidelines align with the trial evidence from China, even though the agency does not specify a minimum number of outdoor minutes per day. For families looking for a concrete target, the Guangzhou trial’s additional 40-minute outdoor session offers a reasonable starting point backed by published data, especially when combined with habits such as the “20-20-20” rule (looking at something 20 feet away for 20 seconds every 20 minutes of close work) to give the focusing system regular relief.
Schools can also make low-cost adjustments that fit within existing schedules. Short outdoor breaks between classes, moving some lessons to shaded courtyards or playgrounds, and raising indoor light levels in classrooms where students spend long stretches reading or writing all move in the direction suggested by the SUNY hypothesis. None of these changes require eliminating digital tools or dramatically cutting academic expectations; instead, they rebalance the visual environment so that intense near work is offset by periods of brighter, more distant viewing. As researchers continue to test whether dim indoor light is a primary driver of myopia, the combination of more outdoor time, better lighting, and smarter breaks offers a pragmatic way to slow a trend that genetics alone cannot explain.
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*This article was researched with the help of AI, with human editors creating the final content.
