CAN SUNLIGHT PRESERVE THE EYES?

Nearsightedness (myopia) has become a pandemic in its own right. According to a 2020 estimate, 2.6 billion people around the world are nearsighted, a figure that is expected to rise to 4.9 billion by 2050 unless action is taken. According to a warning from the European Society of Ophthalmology, “Pathological myopia is forecast to become the most common cause of irreversible vision impairment and blindness worldwide.” A recent review found myopia in 42% of North American children, while in East Asia the figure is a whopping 73%. But what causes myopia? ESO guidance cites an interplay of genetic and environmental factors. With regard to the latter, spending more time at school as well as reading and up-close screen time have been thought to promote myopia, but now new research suggests low dopamine levels contribute to the elongation of the eyeballs that is the hallmark of the condition. Animal studies have revealed that an adequate level of dopamine is associated with the correct length of the eyes. Crucially, a lack of sunlight decreases levels of this neurotransmitter. Thus the principal recommendation for preventing myopia focuses on sunlight and fresh air: Studies have shown that the likelihood of becoming myopic is reduced by about one-third if time spent outdoors is increased from under 5 hours per week to more than 14 hours.