New Study Reveals How Myopia Alters Eye Coordination and Pupil Responses
Key Takeaways
Eye focus, alignment, and pupil size all increase with visual contrast, but these responses are exaggerated in people with myopia.
Accommodation is driven more strongly by OFF retinal pathways than ON pathways, especially in myopic eyes.
Myopia is associated with excessive eye convergence and pupil constriction during near focusing.
A new study published in Cell Reports sheds fresh light on how myopia affects not just how the eye sees, but how it moves and adapts during everyday visual tasks.
According to the researchers, vision is an active process. As we explore our surroundings, the eyes constantly adjust their focus (accommodation), angle toward each other (vergence), and pupil size to optimize visual clarity. These adjustments are guided by visual contrast signals processed through two major retinal pathways: ON pathways, which respond to increases in light, and OFF pathways, which respond to decreases.
Previous research has shown that in myopia, ON retinal pathways tend to be weaker, slower, and less sensitive. The new study goes further, revealing that myopia also disrupts the motor side of vision—how the eyes and pupils physically respond to visual input.
The researchers found that as visual contrast increases, accommodative eye vergence and pupil constriction increase in all participants. However, in people with myopia, these responses were exaggerated.
Compared with individuals without refractive errors, myopic participants showed:
Excessive accommodative eye vergence, meaning their eyes converged more than necessary when focusing
Excessive pupil constriction during accommodation
Reduced dominance of ON pathways, with accommodation driven more strongly by OFF pathways
Disrupted coordination between pupil constriction and eye blinks, a modulation seen in non-myopic eyes
Notably, accommodative contrast sensitivity—the eye’s ability to adjust focus in response to contrast—was higher for OFF pathways than ON pathways, a difference that was amplified in myopia.
The findings point to a potentially self-reinforcing mechanism in myopia progression. Excessive pupil constriction during near focusing may further weaken ON pathway signaling by reducing the light and contrast reaching the retina. This could deepen existing ON pathway deficits and exacerbate visual strain.
This mechanism may help explain why myopia tends to worsen with prolonged near work. Activities such as reading or screen use maximize accommodative pupil constriction, while activities known to slow myopia progression—such as outdoor exposure, atropine treatment, positive defocus, and low-contrast viewing—reduce it. By linking sensory deficits in retinal pathways with abnormal visuomotor responses, the study offers a more integrated view of myopia as a disorder affecting both visual processing and eye movement control.
These insights may inform future strategies for myopia prevention and management, particularly interventions aimed at reducing excessive accommodation and pupil constriction during near tasks.
Originally published online on Eyewire+.