A diet rich in omega-3 fatty acids may help prevent nearsightedness, while a diet high in saturated fats may boost the risk of the condition, according to new findings published in the British Journal of Ophthalmology.

In the observational study, researchers evaluated data from over 1,000 children between the ages of 6 and 8 years old from the Hong Kong Children Eye study, which sought to track the development of eye conditions and potential risk factors.

The children’s eyesight was assessed and compared against food frequency questionnaires, which were completed with the help of the children’s parents. This included 280 items placed into 10 groups.

Intakes of energy, carbohydrate, proteins, total fat, saturated fats, monounsaturated fats, polyunsaturated fatty acids (PUFAs), cholesterol, iron, calcium, vitamins A and C, fiber, starch, sugar, and other nutrients were calculated based on questionnaire responses.

The amount of time children spent outdoors in leisure and sports activities, reading and writing, and on screens during weekdays and over the weekend was also calculated via questionnaire.

Myopia was found in 27.5% of children, and a higher dietary intake of omega-3 fatty acids was associated with a lower risk of the condition.

Axial length, which measures the eye from the cornea at the front to the retina at the back, which is an indicator of myopia progression, was longest in the 25% of children with the lowest dietary intake of omega-3 fatty acids, after accounting for other risk factors like age, sex, weight, time spent in close work and outdoors, and parental myopia. Axial length was shortest in 25% of children with the highest dietary intake of omega-3 fatty acids.

Similarly, cycloplegic spherical equivalent, which measures refractive error including the degree of near-sightedness, was highest in those with the lowest omega-3 fatty acid intake and lowest in those with the highest intake.

Meanwhile, high saturated fats in the diet were correlated with stronger indicators of near-sightedness, while low intakes of saturated fats appeared to prevent myopia progression markers. In the study population, no other nutrients were associated with these two measures of myopia.

It’s been proposed that omega-3 fatty acids might reduce the risk of myopia by increasing blood flow through the choroid, a vascular layer in the eye that delivers nutrients and oxygen. This could stave off oxygen deficiency in the white of the eye, which is a key factor in the development of nearsightedness, the authors concluded.