More than a third of the world's population suffers from myopia, and in 2000 this figure was about one and a half times lower. The reasons for such a widespread decline in vision are actively being studied by the scientific community. Recent research suggests that previous methods of addressing this problem may have been ineffective due to a misunderstanding of its underlying mechanisms.

Factors Contributing to the Spread of Myopia

In the 21st century, the rapid increase in myopia cases has often been linked to more time spent in front of screens—computers, smartphones, and tablets. However, this hypothesis has been questioned, since even in 2000, about 23% of the global population was nearsighted, despite relatively low screen time in most countries. Several scientific studies have shown that a more significant factor is the lack of time spent outdoors in daylight during childhood. The less time a child spends outside, the higher the risk of developing myopia as an adult. This has been associated with the positive effects of ultraviolet light on vision.

A New Explanation of the Mechanism

A study published in Cell Reports offers an alternative explanation. According to this new hypothesis, the main risk factor is prolonged eye strain under low lighting conditions, which are typical indoors. Outdoors, the level of visible light can reach hundreds of watts per square meter, allowing the pupil to constrict while still letting enough light reach the retina. Indoors, when focusing on nearby objects (such as a phone, tablet, or book), the pupil also constricts, but the lighting is much lower—usually not exceeding a few dozen watts per square meter, and during the day it can be many times lower than outside. As a result, despite the constriction of the pupil, the retina receives less light than is necessary for normal function.

An Evolutionary Perspective

For the past two million years, it has been more important for humans to see into the distance than to focus on close objects. Therefore, the human eye is not fully adapted to prolonged close-up work, especially under insufficient lighting.

Possible Prevention Methods

Researchers suggest that the development of myopia can be slowed or prevented by exposing the eyes to bright light under conditions that prevent the pupil from constricting. This can be achieved using special lenses (multifocal or contrast-reducing) or medications that block the muscles responsible for pupil constriction, such as atropine eye drops.

An alternative method remains regular time spent outdoors and looking into the distance. However, in modern life, people rarely spend several hours a day outside. The use of enhancing lenses and atropine drops may be a more practical way to slow the progression of myopia, as shown in several studies on animal models and in children.

Limitations and Future Prospects

Despite the novelty of this approach, questions remain about how this hypothesis aligns with the previously established correlation between time spent outdoors in childhood and the risk of developing myopia in adulthood. Large-scale studies based on the proposed hypothesis are needed to confirm the mechanism definitively.