New research indicates that dim indoor lighting, rather than screen time, may contribute to the rising rates of myopia, which could affect nearly half of the global population by 2050.
Recent studies have highlighted a concerning trend: nearsightedness, or myopia, is on the rise worldwide. The World Health Organization estimates that by 2050, nearly half of the global population will be affected by this vision issue.
While heavy use of smartphones and other digital devices has been linked to an 80% increased risk of myopia—especially when combined with excessive computer usage—new research suggests that dim indoor lighting may also play a significant role in this epidemic.
For years, scientists have sought to understand the various triggers of myopia. Laboratory experiments have shown that myopia can be induced by blurring vision or using different lenses. Conversely, spending time outdoors has been found to slow its progression, indicating that environmental factors are at play.
According to the American Optometric Association (AOA), myopia occurs when the eyeball elongates too much from front to back. This elongation causes light to focus in front of the retina, resulting in distant objects appearing blurry.
Researchers at the State University of New York (SUNY) College of Optometry have identified a potential trigger for this elongation. When individuals focus on close objects, such as smartphones or books, their pupils naturally constrict. However, this constriction is not solely a response to brightness; it also serves to sharpen the image.
Urusha Maharjan, a doctoral student at SUNY Optometry who conducted the study, explained, “In bright outdoor light, the pupil constricts to protect the eye while still allowing ample light to reach the retina.” She further noted that in dim lighting, the combination of focusing on close objects and a narrowed pupil can significantly reduce the amount of light reaching the retina.
The researchers propose that when the retina is deprived of adequate light during prolonged close-up tasks, it sends signals for the eye to grow. In dim environments, the limited light reaching the retina may not be sufficient to halt this growth, leading to an increased risk of myopia.
In contrast, outdoor environments provide much brighter light levels than indoor settings. This ensures that even when the pupil narrows to focus on nearby objects, the retina still receives a strong signal, promoting healthy eye development.
The research team acknowledged some limitations of their study, including a small subject group and the challenge of directly measuring internal lens changes. The bright backgrounds used to simulate outdoor conditions resulted in pupils being too small for standard measurement equipment.
“This is not a final answer,” said Dr. Jose-Manuel Alonso, a distinguished professor and senior author of the study. “But the study offers a testable hypothesis that reframes how visual habits, lighting, and eye focusing interact.”
The findings of this study were published in the journal Cell Reports, and they open new avenues for understanding the relationship between lighting conditions and eye health.
As the prevalence of myopia continues to rise, it becomes increasingly important to consider how our indoor environments may contribute to this global health issue. Adjusting lighting conditions and encouraging outdoor activities could be vital steps in mitigating the myopia epidemic.
For more information on this topic, refer to the research conducted by the SUNY College of Optometry.