October 1, 2025
By Kevin Chan, OD, MS, FAAO, IACMM
Photo Credit: Getty Images
A recent article by XJ Zhang et al. investigated the potential role of dietary omega-3 polyunsaturated fatty acids (PUFAs) in protecting against childhood myopia. Previous animal studies found that omega-3 PUFAs could slow and inhibit myopia progression via modification of choroidal vasculature and scleral hypoxia.
In this study, the data was collected and reported using human data from the Hong Kong Children Eye Study. As myopia has grown as a global public health concern, particularly in East Asian populations, treatment for myopia progression has evolved as a comprehensive, holistic approach. Currently, myopia management encompasses nutritional guidelines that could potentially help steer public health strategies to slow or prevent the progression of myopia among children.
Study Design and Methods
The research utilizes a cross-sectional study design for 1,005 Chinese children aged 6 to 8 years from Hong Kong. Dietary intake of omega-3 PUFAs was assessed through validated food frequency questionnaires (FFQ) completed by the participants and/or their guardians. Measuring parameters included ocular measurements like refractive error and axial length. These were obtained using standardized ophthalmologic examinations. The study controlled for potential confounders such as age, sex, parental myopia, time spent outdoors and near work activities.
Key Findings
- Children with higher dietary intake of omega-3 PUFAs demonstrated a lower prevalence of myopia compared to those with lower intake.
- There was a statistically significant negative correlation between increased omega-3 PUFA consumption and reduced axial elongation. This is a key risk factor for myopia progression.
- The authors reported the protective effect of omega-3 PUFAs was found to be independent of other known risk factors. This suggests a potential biological mechanism through which these fatty acids may influence ocular growth and development.
- The findings support the hypothesis that dietary modification, specifically increased omega-3 intake, could be a sound clinical guideline. Moreover, this could be translated to public health interventions to mitigate the risk of myopia in children.
Key Implications and Future Directions
Several limitations were present and reported in this study:
- A cross-sectional study design is generally not ideal to extrapolate temporal or causal relationships between dietary intakes and development of myopia. To further validate the clinical association, or even causation, it warrants a longitudinal study design with single or double-blind subjects to substantiate the evidence among the cohort groups.
- The population studied are predominantly children of Chinese descent. It represents a homogeneous study group that may not reflect the dietary intake of omega-3 PUFAs for children of all ethnicities.
- Acquiring data via a questionnaire provides only a snapshot of children’s food intake. It can be subject to recall bias and reporting errors that may impact the ‘real’ nutritional intakes by the subjects. It was uncertain whether children in the subject group had any dietary shifts or preferences. This could be a confounder for the study result.
- A more objective and robust parameter to record dietary intakes, such as serum biomarkers, was absent in the study.
Conclusions
The study has contributed human data to help elucidate the plausible evidence that links nutrition and eye health. It specifically highlights the role of omega-3 PUFAs as a promising protective factor for myopia. The potential of PUFAs against scleral hypoxia and retinal blood flow could further our understanding of the next frontier of myopia treatment.
The cross-sectional study design limits causal inference. However, the robust association observed in this study sparks further interest and exploration of the causal relationships between nutritional intakes and myopia development via longitudinal, randomized clinical trial studies. This is considered a significant contribution to the existing clinical evidence. It could also directly impact the trajectory of nutritional guidelines and public health strategies, particularly for those at-risk or in areas where diets in high saturated fat content are favored.
Abstract
Purpose
To evaluate the associations between omega-3 polyunsaturated fatty acids (ω-3 PUFAs) and other dietary factors with myopia.
Methods
A total of 1005 Chinese children, aged from 6 to 8 years, from a population-based Hong Kong Children Eye Study, were included in the analysis. Diet was assessed using a validated food-frequency questionnaire. Cycloplegic spherical equivalent (SE) refraction was assessed with an autorefractometer, and axial length (AL) by an IOL Master.
Results
AL was longest in the lowest quartile group of ω-3 PUFAs intake, compared with the highest (adjusted mean (95% CI), 23.29 (23.17 to 23.40) mm vs 23.08 (22.96 to 23.19) mm, p=0.01; p-trend=0.02) after adjusting for age, sex, body mass index, near-work time, outdoor time, and parental myopia history. The corresponding trends were observed in SE (-0.13 (-0.32 to 0.07) D in the lowest and 0.23 (0.03 to 0.42) D in the highest quartile groups, p=0.01; p-trend=0.01).
In contrast, AL was longest in the highest quartile group of saturated fatty acids (SFA) intake, compared with the lowest (23.30 (23.17 to 23.42) mm vs 23.13 (23.01 to 23.24) mm, p=0.05; p-trend=0.04). The corresponding trends were observed in SE (-0.12 (-0.33 to 0.09) D in the highest and 0.13 (-0.04 to 0.31) D in the lowest quartile group, p=0.06; p-trend=0.04). A lower intake of ω-3 PUFAs was associated with myopia (p-trend=0.006). None of the other nutrients were associated with SE or AL or myopia.
Conclusions
Intake of ω-3 PUFAs is a protective factor against myopia, while higher SFA intake is a risk factor. Our findings indicated a possible effect of diet on myopia, of which ω-3 PUFAs intake may play a protective role against myopia development in children.
