| I have worn glasses for nearly as long as I can remember. Growing up in Hong Kong, that felt completely normal. By some estimates, as much as 87% of young adults and more than 60% of 12-year-olds in the city are myopic. The long-term consequences of myopia are not just cosmetic. When someone is near-sighted, their eyeballs get longer and longer. That can lead to future complications such as macular degeneration and retinal detachment glaucoma. In the worst case scenario, it can result in blindness. That’s why it’s important to prevent myopia in children, says Jason Yam, professor in the ophthalmology and visual sciences department at the Chinese University of Hong Kong. He led a team of researchers behind a new study looking for factors that may worsen or protect against myopia progression by tracking what children eat. In the end, one ingredient stood out: omega-3 polyunsaturated fatty acids, which is commonly found in fish. Among more than 1,000 6-to-8-year-olds studied , those who reported eating more omega-3 as part of their diet ended up with less myopia, the researchers wrote in the British Journal of Ophthalmology. That’s after adjusting for other factors such as age, sex and time spent in close work. Omega-3, of course, is known to have other health benefits, particularly for the heart. This new study provides some of the first human evidence to suggest it may also help with myopia, Yam says. There are a few theories on how myopia develops, Yam says, and one posits that it has to do with a lack of oxygen in the sclera, the tough, white, outer layer of the eyeball. Previous animal studies suggest that omega-3 helps increase blood flow in the inner choroid layer and brings more oxygen to the sclera, thereby slowing myopia progression. To be sure, the magnitude of the effect appears moderate, especially when compared to other interventions such as atropine eye drops (as shown in another study led by Yam) and red light therapy. But omega-3 can be supplementary and have a wide public health impact. “Not every child needs treatment, but every child can take a healthy diet,” Yam says. This could be particularly relevant in Hong Kong, where most parents have myopia – increasing the chances that their children will have it too – and outdoor time, a highly effective preventative measure, is often considered a luxury. As for whether these findings might apply to children in other areas, Yam says that while the biological effect of omega-3 should be generalizable, differences in culture and myopia prevalence may lead to different outcomes. The researchers are currently planning a new study to see whether taking fish-oil supplements will keep children from developing myopia. Sounds like time to stock up before more Hong Kong parents find out. — Amber Tong | 
