Fatty Acid Essential For Mental And Visual Function. Docosahexaenoic acid (dha) is a fatty acid essential for mental and visual function. It is the primary structural fatty acid in the gray matter of the brain and retina of the eye and is important for signal transmission in the brain, eye and nervous system. Low levels of dha have been correlated with changes in disposition, memory loss, visual function and other neurological conditions. Nature's Way is committed to providing the highest quality natural supplements available. Every product is formulated with the utmost concern for potency, purity, and effectiveness.