Summary: The global surge in myopia (nearsightedness) is often blamed on screens, but new research suggests a more physiological culprit: low retinal illumination. The study proposes that when we perform sustained “near work” indoors, like reading a book or scrolling on a phone—our pupils constrict to sharpen the image (accommodation).
In dim indoor lighting, this constriction, combined with low ambient light, starves the retina of the robust activity it needs to stay healthy. This “light starvation” may be the unifying mechanism that explains why outdoor time prevents myopia and why certain treatments, like atropine drops (which dilate the pupil), actually work.
Key Facts
- The “Light Starvation” Hypothesis: Myopia may be driven by a lack of light reaching the retina due to the double whammy of dim indoor settings and pupil constriction during close-up focus.
- Pupil Constriction Deficit: When we focus on things close-up, the pupil constricts for clarity (not just brightness). In low light, this reduces retinal activity to dangerously low levels.
- The Role of Accommodation: Prolonged close-up focus (accommodation) for tens of minutes makes this pupil constriction even stronger, especially in those who are already nearsighted.
- Unifying Theory: This mechanism explains why outdoor time (bright light/no near focus), atropine (pupil dilation), and multifocal lenses (reduced focus effort) all help control myopia.
- A Global Epidemic: Myopia now affects nearly 50% of young adults in the U.S. and Europe, and up to 90% in parts of East Asia.
Source: SUNY
For years, rising rates of myopia — or nearsightedness — have been widely attributed to increased screen time, especially among children and young adults. But new research from scientists at the SUNY College of Optometry suggests the story may be more complicated — and more human.
In a new study to be published in Cell Reports, researchers propose that myopia may be driven less by screens themselves and more by a common indoor visual habit: prolonged close-up focus in low-light environments, which limits how much light reaches the retina.
“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.
“Our findings suggest that a common underlying factor may be how much light reaches the retina during sustained near work — particularly indoors.”
Myopia (nearsightedness) is a visual disease that blurs vision at far distance and is becoming a world epidemic affecting nearly 50 percent of young adults in the United States and Europe and close to 90 percent in parts of East Asia. While genetics play an important role, rapid increases over just a few generations suggest environmental factors are also critical.
The disease can be induced in animal models with visual deprivation or negative lenses, and the two induction processes are thought to involve different neuronal mechanisms. Clinicians also control myopia progression with a variety of approaches that are thought to engage multiple mechanisms (multifocal lenses, ophthalmic atropine, contrast-reduction, promoting time outdoors, and others).
Scientists at the State University of New York (SUNY) College of Optometry propose a unifying neuronal mechanism in their article to explain all current approaches to myopia induction and control.
The research offers a new hypothesis that could help explain a long-standing puzzle in vision science — why so many seemingly different factors, from near work and dim indoor lighting to treatments like atropine drops, multifocal lenses, and time spent outdoors, all appear to influence myopia progression.
“In bright outdoor light, the pupil constricts to protect the eye while still allowing ample light to reach the retina,” explains Urusha Maharjan, SUNY Optometry doctoral student who conducted 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.”
According to this mechanism, myopia develops when poor retinal illumination fails to generate robust retinal activity because the light sources are too dim and pupil constriction is too excessive at short viewing distances. Conversely, myopia does not develop when the eye is exposed to bright light and the pupil constriction is regulated by image brightness instead of viewing distance.
The new study demonstrates that negative lenses reduce retinal illumination by constricting the pupil through a process known as accommodation (i.e., an accommodative increase in the lens power of the eye when focusing images at short distances).
Such pupil constriction becomes stronger when accommodation is increased by shortening viewing distance or wearing excessively-strong negative lenses. Moreover, pupil constriction becomes even stronger when lens accommodation is sustained for prologued periods of time (e.g., tens of minutes), and even stronger when the eye becomes myopic.
The study also demonstrates additional myopia disruptions of eye turning with accommodation and eye-blink efficacy at constricting the pupil.
If proven correct, the mechanism proposed could lead to a paradigm shift in our understanding of myopia progression and control. According to this mechanism, myopia can be controlled by exposing the eye to safe bright light levels under limited accommodative pupil constriction.
Accommodative pupil constriction can be limited by reducing accommodation strength with lenses (multifocal or contrast-reduction), blocking directly the muscles driving pupil constriction (atropine drops), or by simply spending time outdoors without engaging accommodation (looking at far distances).
Perhaps most importantly, the new mechanism predicts that any approach to myopia control will fail if the eye is exposed to excessive accommodation indoors under low light for prolonged periods of time.
“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.”
The research was done by Urusha Maharjan and collaborators in the laboratories of Jose-Manuel Alonso at the SUNY College of Optometry.
Key Questions Answered:
A: It’s both, but the light is the “why.” Using a screen indoors involves focusing close-up (which shrinks your pupil) in a room that is already much dimmer than the outdoors. This combo means your retina isn’t getting enough “input” to maintain its proper shape.
A: Two reasons: first, the light is thousands of times brighter, ensuring your retina is well-fed even with a small pupil. Second, you spend more time looking at far-off objects, which allows your pupil to relax and stay open.
A: It helps! The researchers suggest that myopia control fails if the eye is exposed to excessive “near work” under low light for too long. Keeping your workspace brightly lit and taking breaks to look at a distance are simple, science-backed preventative steps.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this visual neuroscience research news
Author: Maria O’Brien
Source: SUNY
Contact: Maria O’Brien – SUNY
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Human accommodative visuomotor function is driven by contrast through ON and OFF pathways and is enhanced in myopia” by Urusha Maharjan, Hamed Rahimi-Nasrabadi, Sabina Poudel, Farzaneh Olianezhad, Jianzhong Jin, Mitchell W. Dul, and Jose-Manuel Alonso. Cell Reports
DOI:10.1016/j.celrep.2026.116938
Abstract
Human accommodative visuomotor function is driven by contrast through ON and OFF pathways and is enhanced in myopia
The human eyes are continuously adjusting refractive power, vergence angle, and pupil diameter when exploring the visual environment.
Adjustment errors in these visuomotor functions reduce the stimulus contrast driving ON and OFF retinal pathways, and ON retinal pathways become weaker, slower, and less sensitive in refractive disorders such as myopia.
Here, we demonstrate that, in addition to these sensory deficits, myopes also have deficits in visuomotor functions driven by ON and OFF pathways during lens accommodation.
We show that humans with myopia have excessive accommodative eye vergence with reduced ON pathway dominance and excessive accommodative pupil constriction. The excessive accommodative pupil constriction that we demonstrate could potentially weaken ON pathway responses and cause ON pathway deficits.
This mechanism could explain why myopia increases with activities that maximize accommodative pupil constriction, such as near work, and decreases with activities/treatments that reduce it, such as outdoor activity, atropine, positive defocus, and low contrast.
