Video shows eyes while performing two different tasks: reading versus walking. Courtesy of Jose-Manuel Alonso, SUNY College of Optometry.
Researchers at the State University of New York (SUNY) help explain how reading might contribute to myopia. A team led by Jose-Manuel Alonso found that the images formed by our eyes during reading lack the diversity of contrasts, luminance transients, visual motion, and visual change needed to activate major visual pathways signaling light stimuli, generally known as ON pathways. Their work could open new lines of myopia prevention and treatment based on visual diets that boost ON pathway activation.
The study compared the eye visual input and visuomotor activity generated by humans performing two visual tasks that are associated with different risk of myopia progression, reading (high risk) and walking (low risk). The results indicate that multiple factors including low light, low contrast, and the lack of self-motion make reading less effective at driving ON pathways than walking. Based on these results, the paper proposes a mechanism of myopia development that requires ON pathways to be strongly activated along the day to properly adjust eye growth. Under this mechanism, sustained reading for prolonged periods of time reduces the activation of ON pathways making the eye grow beyond its focus plane and blurring vision at far distance.