Dim Lights and Close-Up Work: The Real Culprits Behind the Myopia Epidemic
For years, increasing screen time has been blamed for the global rise in myopia, or nearsightedness, particularly among children and young adults. But, emerging research suggests the issue is more complex. A new study from the SUNY College of Optometry proposes that prolonged close-up focus in low-light environments, rather than screens themselves, may be a primary driver of myopia development.
Myopia Rates Are Climbing Worldwide
Myopia causes distant objects to appear blurry and is becoming increasingly prevalent worldwide. Currently, it affects nearly 50 percent of young adults in the United States and Europe, and close to 90 percent in parts of East Asia [1]. While genetics play a role, the rapid increase in cases over recent generations strongly indicates environmental factors are at play.
A New Theory About Retinal Light and Eye Focus
Researchers at the SUNY College of Optometry are proposing a unifying neuronal mechanism to explain how various factors influence myopia. This new hypothesis attempts to answer a long-standing question in vision science: why do factors like close-up work, dim indoor lighting, atropine drops, multifocal lenses, and time spent outdoors all seem to affect myopia progression [2]?
“Myopia has reached near-epidemic levels worldwide, yet we still don’t fully understand why,” said Jose-Manuel Alonso, MD, PhD, SUNY Distinguished Professor and senior author of the study [1]. “Our findings suggest that a common underlying factor may be how much light reaches the retina during sustained near work — particularly indoors.”
The study suggests that when focusing on nearby objects indoors, the pupil constricts to sharpen the image. In dim lighting, this constriction, combined with low ambient light, may reduce the amount of light reaching the retina, potentially triggering changes that lead to nearsightedness [4].
How Accommodation and Negative Lenses Play a Role
The research also found that negative lenses can decrease retinal illumination by causing the pupil to narrow through accommodation – the process where the eye’s lens changes shape to focus on objects at different distances. This narrowing intensifies when viewing distance is shortened or when overly strong negative lenses are worn, and is exacerbated by prolonged accommodation [4]. Researchers also observed disruptions in eye turning during accommodation and reduced effectiveness of eye blinks in triggering pupil constriction in myopic eyes.
Implications for Myopia Prevention and Treatment
If validated, this proposed mechanism could significantly change how scientists and clinicians approach myopia progression. The theory suggests that maintaining adequate light exposure while limiting excessive pupil constriction during close-up work may facilitate control myopia. This can be achieved by reducing accommodative demand with lenses (multifocal or contrast-reduction), dilating the pupil with atropine drops, or spending time outdoors [2].
Researchers emphasize that treatment approaches may be less effective if individuals continue prolonged close-up focusing indoors under dim lighting conditions [1].
“This is not a final answer,” Alonso emphasized [1]. “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.”