Fish oil and fatty fish help prevent nearsightedness in children

Nearsightedness is a vision condition that typically begins in childhood and often worsens during adolescence. However, a diet rich in omega-3 fatty acids from fatty fish appears to reduce the risk of children and adolescents developing nearsightedness, according to a Chinese study published in the British Journal of Ophthalmology. The findings also suggest that the omega-3 fatty acid DHA, found in fatty fish and fish oil supplements, plays a particularly important role in eye health.

Nearsightedness (myopia) is a vision condition in which close-up objects are seen clearly, while distant objects appear blurred. It can make it difficult or impossible to read the blackboard at school, see road signs, or recognize faces from a distance. It can also lead to headaches and eye strain. Nearsightedness is usually corrected or treated with glasses or contact lenses (minus lenses) or, in some cases, surgery.
Nearsightedness mainly occurs when the eyeball is too long or when the cornea or lens bends light too strongly. The condition often worsens during childhood or adolescence. New concerning risk factors include excessive screen time and insufficient time spent outdoors, where children would normally encounter distant objects in natural and urban environments. As a result, many children over-stimulate their near vision while under-stimulating their distance vision.
The prevalence of nearsightedness among children and adolescents is therefore rising sharply. With estimates suggesting that half of the world’s population will be nearsighted by 2050, it is important to focus on prevention or early diagnosis to slow its progression.
It is well known that the omega-3 fatty acid DHA, found in fatty fish, cod liver oil, and fish oil supplements, is crucial for normal vision development in fetuses and infants. Fish oil is also known to help prevent or improve various eye conditions such as dry eyes and age-related macular degeneration (AMD). However, it has been unclear whether omega-3 fatty acids can specifically help prevent the development of nearsightedness in children.
The new study included over 1,000 Chinese children aged 6–8 years, recruited from the population-based Hong Kong Children Eye Study, which investigates the development of eye diseases in children and potential risk factors.
The children underwent vision tests, and their diets were assessed using detailed questionnaires completed with parental help. The questionnaires covered 280 food items, categorized into ten subgroups: starches (bread, cereals, pasta, rice, noodles), vegetables/legumes, fruit, meat, fish, eggs, milk/dairy products, beverages, dim sum (Chinese snacks), and fats/oils and soups.
Based on the questionnaires, the researchers calculated the children’s intake of energy, carbohydrates, protein, total fat, saturated fat, monounsaturated fat, polyunsaturated fat (omega-6 and omega-3), cholesterol, iron, calcium, vitamins A and C, and fiber.
The researchers also assessed how much time the children spent indoors during the week and on weekends, including reading, writing, and screen time, as well as time spent outdoors on sports and other activities.

Higher intake of fatty fish protects against nearsightedness through multiple mechanisms

The study found that one-quarter of the children were nearsighted, and that a higher intake of omega-3 fatty acids from fatty fish and other sources was associated with a lower risk of developing the condition. Additionally, the researchers observed that the eyeball length was longest among children with the lowest omega-3 intake. This finding remained significant even after adjusting for factors such as age, sex, BMI, hours spent indoors or outdoors, and family history of nearsightedness. None of the other nutrients were related to the development of nearsightedness.
Since Hong Kong has one of the highest rates of nearsightedness in the world, the researchers note that the prevalence may be lower in other ethnic groups for other reasons.
Nevertheless, the findings suggest that omega-3 fatty acids may help prevent the development of nearsightedness in children by improving blood flow to the choroid, which supplies the outer layers of the retina with oxygen and nutrients. In general, omega-3s may help prevent oxygen and nutrient deficiencies in the eye - a key factor in the development of nearsightedness, in part because eyeball elongation is involved.

The importance of DHA for eye health

• Supports normal vision development in fetuses and infants
• Maintains healthy eye structure
• Supports retinal cells (photoreceptors)
• Stabilizes tear film and protects against dry eyes
• Protects the eye from oxidative stress
• Helps prevent age-related macular degeneration (AMD)
• Helps prevent the development of nearsightedness in children and adolescents

Reference

Zhang, X.J., et al. Dietary omega-3 polyunsaturated fatty acids as a protective factor of myopia. The Hong Kong Children Eye Study. British Journal of Ophthalmology. 2025

BMJ Group. Omega-3 rich diet linked to lower risk of childhood myopia. 2025