Medical professionals and researchers are sounding the alarm: myopia, or nearsightedness, is rapidly spreading worldwide.
A team of researchers from the State University of New York College of Optometry (SUNY) says the problem goes beyond just how much time people spend on close-up tasks. That is only one of the key factors driving the trend.
It turns out that myopia is largely influenced by:
- a tendency to stay indoors and focus on nearby objects;
- the habit of working for extended periods in low light and at close distances, and most importantly — the amount of light reaching the retina under these conditions.
What Did the Scientists Report?
The SUNY team involved 34 volunteers in their laboratory studies. Of these, 21 were myopic, while 13 had normal vision. Participants were asked to repeatedly focus, alternating between each eye, on square targets that varied in brightness and contrast.
By observing the eye movements of people with myopia, the researchers suggested that close-up activities may contribute to the development of myopia by triggering pupil constriction. That constriction reduces the amount of light entering the eye, ScienceAlert reported.
“Myopia has reached nearly epidemic proportions worldwide, yet we still do not fully understand why. Our results suggest that a key factor may be the amount of light reaching the retina during prolonged close-up work, especially indoors,” noted co-author José-Manuel Alonso, a neurobiologist specializing in vision research.
The researchers aimed to study three behavioral aspects related to viewing nearby objects: eye focusing (accommodation), eye convergence (turning inward), and pupil constriction. The team adjusted their analysis to account for activation of the ON and OFF pathways in the retina, which process light and darkness, respectively.
Previous studies indicated that optic nerve weakening is associated with myopia; however, the underlying mechanism remained unclear. One of the team’s key findings was that contrast affected eye convergence and pupil constriction more than overall brightness did.
The team also noted that myopic individuals tend to have their eyes turned inward even before focusing, and their pupils constrict more than those of people with normal vision.
Based on these observations, the researchers proposed a new hypothesis: in myopia, the visual system prioritizes focus over brightness. That becomes a significant issue in low-light environments.
“In bright sunlight, the pupil constricts to protect the eye while still allowing enough light to reach the retina. When people focus on nearby objects indoors, such as phones, tablets, or books, the pupil may constrict not because of brightness but to enhance image sharpness. If that is compounded by low light, retinal illumination drops significantly,” explained Urusha Mahardjan, a graduate optometry student and study participant.
The team wrote, “Our results support the hypothesis that myopia develops in children with insufficient retinal stimulation.”
The findings were published in the journal Cell Reports.
Experts predict that by 2050, approximately 40 percent of young people worldwide will suffer from myopia.
Photo: Unsplash
