Nearsightedness and Omega-3 Fatty Acids

Nearsightedness, or myopia, is a visual problem that is significantly increasing worldwide, particularly in East Asian countries. Many children suffer from it, and researchers predict that half of the world’s population will be affected by this condition by 2050. Studies have shown that genetic and environmental factors, such as spending long periods in front of screens and limited time outdoors, may increase the risk of developing nearsightedness. In light of these circumstances, omega-3 fatty acids emerge as a potential treatment, known for their numerous health benefits. But can they help prevent nearsightedness?

Case Study: Children in Hong Kong

A study was conducted on 1,005 Chinese children aged 6 to 8 years as part of the Hong Kong Children Study. The aim was to track the development of visual conditions and their causative factors. The children’s vision was assessed, and their regular diet was determined using a food frequency questionnaire with the help of their parents.

The questionnaire included 280 food items categorized into 10 groups such as bread, cereals, pasta, rice, vegetables, fruits, meats, fish, eggs, dairy products, beverages, snacks, and soups. Based on the responses, the intake of energy, carbohydrates, proteins, fats, cholesterol, iron, calcium, vitamins, fiber, starches, sugar, and nutrients was calculated.

Study Results and the Role of Omega-3 Fatty Acids

The results showed that about a quarter of the children (276 children) were nearsighted. The study indicated that higher consumption of omega-3 fatty acids is associated with a reduced risk of this condition. The axial length of the eye, an indicator of myopia progression, was longer in children with the lowest omega-3 fatty acid intake after considering influencing factors such as age, gender, weight, time spent on near activities and outdoors, and parental myopia.

Conversely, the axial length was shorter in children with the highest omega-3 fatty acid consumption. There was also a correlation between omega-3 fatty acid intake and refractive error measurement, which was higher in children with the lowest intake and lower in those with the highest intake.

Potential Side Effects and Other Factors

It is important to note that this study is observational and therefore cannot conclusively prove causative and temporal factors. The researchers acknowledged that food frequency questionnaires rely on memory and only provide a snapshot of the diet. There was no objective evidence of nutrient intake from blood samples.

Additionally, the prevalence of nearsightedness in Hong Kong is among the highest in the world, and researchers need to verify whether these findings apply to other ethnic groups with different lifestyles and lower myopia prevalence.

Conclusion

The study suggests that omega-3 fatty acids may play a role in suppressing nearsightedness by increasing blood flow through the choroid, a vascular layer in the eye responsible for delivering nutrients and oxygen, thus helping prevent scleral hypoxia, a key factor in myopia development. The researchers emphasized that this study provides human evidence that higher omega-3 fatty acid consumption is associated with shorter axial length and less optical refraction, highlighting omega-3 fatty acids as a potential dietary protective factor against the development of nearsightedness.