Scientists at the SUNY College of Optometry propose that the rapid rise in nearsightedness, or myopia, stems not just from screen time but from prolonged close-up focusing in dim indoor lighting. This combination reduces light reaching the retina, potentially triggering eye changes. The study, set for publication in Cell Reports, offers a unified explanation for various myopia causes and treatments.
Nearsightedness has become increasingly prevalent worldwide, affecting nearly 50 percent of young adults in the United States and Europe, and up to 90 percent in parts of East Asia. While genetics play a role, the swift increase over recent generations highlights environmental factors as key drivers.
A new hypothesis from researchers at the State University of New York College of Optometry suggests that sustained near work in low-light indoor settings is a central culprit. "Myopia has reached near-epidemic levels worldwide, yet we still don't fully understand why," said Jose-Manuel Alonso, MD, PhD, a SUNY Distinguished Professor and the study's senior author. The research indicates that when focusing on close objects like phones or books in dim conditions, the pupil constricts to sharpen the image, limiting retinal illumination.
"In bright outdoor light, the pupil constricts to protect the eye while still allowing ample light to reach the retina," explained Urusha Maharjan, a doctoral student at SUNY Optometry who led the study. "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."
The theory connects diverse myopia influences, including visual deprivation in labs, negative lenses, and treatments like multifocal lenses, atropine drops, and outdoor time. Negative lenses, for instance, narrow the pupil through accommodation, further dimming retinal light, especially during prolonged use or in already myopic eyes.
If confirmed, this mechanism could reshape prevention strategies, emphasizing brighter lighting during close work and reducing accommodative demands. "This is not a final answer," Alonso noted. "But the study offers a testable hypothesis that reframes how visual habits, lighting, and eye focusing interact."
The work, conducted in Alonso's laboratories, appears in the forthcoming issue of Cell Reports.
