Associations Between Circulating Polyunsaturated Fatty Acids and Photoreceptor Measurement

Polyunsaturated fatty acids (PUFAs) are enriched in the retina and may play essential roles in photoreceptor microstructure. This study aimed to investigate associations between circulating omega-3 and omega-6 fatty acid-related measures and photoreceptor inner and outer segment thickness assessed by optical coherence tomography (OCT) in the UK Biobank.

In this cross-sectional association study, circulating omega-3 and omega-6 fatty acid-related measures were quantified using a nuclear magnetic resonance metabolomics platform. Photoreceptor inner segment (IS) and outer segment (OS) thicknesses were measured by spectral-domain OCT obtained during the same baseline assessment period. β coefficients with 95% confidence intervals (CIs) were estimated using linear regression models adjusted for covariates. Restricted cubic spline analyses were performed to assess dose-response relationships, and subgroup analyses examined potential interaction effects.

Higher circulating levels of omega-3 fatty acids were associated with a thinner IS layer (β = -0.059; 95% CI, -0.096 to -0.022; P = 0.002), whereas higher omega-6 fatty acid levels were linked to a thinner OS layer (β = -0.229; 95% CI, -0.338 to -0.121; P < 0.001). These relationships were largely linear within the physiological range. Subgroup analyses indicated that ethnicity modified the association with OS thickness.

Circulating omega-3 and omega-6 fatty acid-related measures were differentially associated with photoreceptor inner and OS thickness measured by OCT, with omega-3-related indices generally associated with thinner ISs and thicker OSs and omega-6-related indices showing opposite patterns.

Maintaining a favorable PUFAs balance may be beneficial for photoreceptor microstructure.