Fish liver oil, particularly cod liver oil, is rich in omega-3 fatty acids (EPA and DHA) and vitamins A and D. There is scientific evidence supporting its role in supporting eye health, primarily due to these nutrients. Vitamin A is essential for the formation of rhodopsin, a protein in the retina that absorbs light and is necessary for both low-light (scotopic) and color vision. Vitamin A deficiency is a leading cause of preventable blindness globally, and supplementation with fish liver oil can help prevent this condition, especially in populations at risk.

Omega-3 fatty acids in fish liver oil have also been studied for their potential to protect against age-related macular degeneration (AMD) and dry eye syndrome. Several observational studies and randomized controlled trials suggest that higher intakes of omega-3s are associated with a reduced risk of AMD progression and improvement in symptoms of dry eye disease. However, results are mixed, and more research is needed to establish definitive recommendations.

In summary, the use of fish liver oil to support eye health is scientifically justified, with the strongest evidence related to vitamin A for preventing deficiency-related vision problems, and suggestive—but less conclusive—evidence for omega-3s in protecting against certain chronic eye conditions.