DHA is docosahexaenoic acid and is an omega-3 fatty acid found in fish oil. A study appearing in the fotolia_2706797 (2)American Journal of Clinical Nutrition (April 2010 91: 848-859) looked at 343 formula-fed infants and the effect DHA fortification had on their visual acuity. The infants were randomly divided into four groups. Each group was given formula containing either 0.32% DHA, 0.64% DHA, 0.96% DHA or a placebo. After one year, it was found that fortifying the formula with DHA improved visual acuity. There was no difference in the amount of improvement between the group receiving 0.32% DHA and those infants receiving the higher doses.