Nearsightedness, also known as myopia, is rising at an alarming rate around the world. The World Health Organization estimates that nearly half of the global population could be myopic by 2050. While digital devices have often been blamed for this surge, new research suggests the real culprit may be something more subtle and widespread: poor indoor lighting during close-up activities.
Scientists at the State University of New York College of Optometry are leading this research, proposing that the combination of prolonged near work and dim light may quietly influence how the eye develops.
What Researchers Are Discovering
The research was conducted by Urusha Maharjan, a doctoral student, in the laboratory of Jose-Manuel Alonso, MD, PhD, a distinguished professor at SUNY Optometry. Their study, published in the journal Cell Reports, offers a new explanation for why myopia develops.
“Myopia has reached near-epidemic levels worldwide, yet we still don’t fully understand why,” Alonso said. “Our findings suggest that a common underlying factor may be how much light reaches the retina during sustained near work, particularly indoors.”
Nearsightedness occurs when the eyeball grows too long from front to back, causing light to focus in front of the retina instead of directly on it. This makes distant objects appear blurry.
The researchers believe insufficient light reaching the retina during extended close-up tasks may signal the eye to continue growing, contributing to myopia progression.
The Role of Lighting and the Pupil
The key mechanism centers on how the pupil behaves. The pupil naturally constricts in bright light to protect the eye. It also constricts when focusing on nearby objects to sharpen the image.
“In bright outdoor light, the pupil constricts to protect the eye while still allowing ample light to reach the retina,” Maharjan explained. “When people focus on close objects indoors, such as phones, tablets, or books, the pupil can also constrict, not because of brightness, but to sharpen the image. In dim lighting, this combination may significantly reduce retinal illumination.”
If the retina receives too little stimulation over time, the neural signals that normally help regulate eye growth may weaken. This may encourage the eye to elongate, leading to nearsightedness.
How Phones and Screens Fit Into the Picture
The study suggests that smartphones and computers themselves may not directly cause myopia. Instead, the environments in which they are used may matter more.
Heavy smartphone use combined with excessive computer time has been associated with an 80 percent higher risk of myopia. However, researchers believe this increased risk may partly come from the low light indoor conditions in which devices are often used.
The scientists emphasize that prolonged close-up focus under dim lighting conditions could be particularly problematic.
Myopia already affects nearly half of young adults in the United States and Europe and close to 90 percent of people in parts of East Asia. The rapid rise over just a few generations strongly suggests environmental factors are playing a major role, since genetic changes alone cannot explain such a shift.
Spending more time outdoors has consistently been shown to protect against myopia, which supports the idea that bright light exposure is important for healthy eye development.
If the new hypothesis proves correct, prevention could be surprisingly simple. Increasing indoor brightness during reading or screen use may help reduce risk.
Bright outdoor light appears especially protective because it ensures strong retinal stimulation even when the pupil constricts during focusing. Other treatments that slow myopia progression, such as atropine eye drops or specialized lenses, may work partly by allowing more light to reach the retina or reducing the strain of close focusing.
Researchers believe that maintaining adequate lighting and spending time outdoors could become important public health strategies.
“This is not a final answer,” Alonso emphasized. “But the study offers a testable hypothesis that reframes how visual habits, lighting, and eye focusing interact. It’s a hypothesis grounded in measurable physiology that brings together many pieces of existing evidence. More research is needed, but it gives us a new way to think about prevention and treatment.”
