That news appears in the advance online edition of the journal Nature Medicine.
Three leading causes of blindness are age-related macular degeneration, diabetic retinopathy, and retinopathy related to premature birth.
Omega-3s may reduce retinopathy, according to the new study, which involved tests on mice.
If the findings apply to people, "simple supplementation [with omega-3 fatty acids] could be a cost-effective intervention benefiting millions of people," says Lois Smith, MD, PhD, in a news release from Children's Hospital Boston.
Smith works in the ophthalmology department of Harvard Medical School and Children's Hospital Boston.
Omega-3 and Omega-6 Fatty Acids
Smith and colleagues studied omega-3 and omega-6 fatty acids in newborn mice.
The body needs omega-3s and omega-6s and must get those fatty acids through diet or supplements.
Western diets tend to be heavy on omega-6s and skimpy on omega-3s.
Omega-6s are found in meat and vegetable oils such as safflower oil, sunflower oil, corn oil, and soy oils. Food sources of omega-3s include leafy green vegetables, walnuts, flaxseeds, and fatty fish such as salmon, herring, and sardines.
Smith's team added omega-3s or omega-6s to the diets of female mice that had just given birth. The mother mice passed the omega-3s or omega-6s to their newborns through their breast milk.
The omega-3 supplements were given at a dose similar to that of the traditional Japanese diet. The omega-6 supplements were given at a dose like that of a typical Western diet.
The baby mice were exposed to high levels of oxygen for five days, starting when they were 1 week old.
Those conditions put the eye at risk of losing healthy blood vessels, which sets the stage for abnormal blood vessels to develop.
The newborn mice kept more of the healthy blood vessels in their eyes if their mothers' diets were supplemented with omega-3s instead of omega-6s.
With more of their healthy blood vessels intact, the newborn mice in the omega-3 group were less likely to have abnormal blood vessels develop in their eyes.
In short, omega-3s reduced retinopathy before it started. The study shows that the results may be related to omega-3s' anti-inflammatory effects.
Premature Retinopathy to Be Studied
Children's Hospital Boston plans to study omega-3s in premature babies, who are at risk for vision loss.
The study would include premature babies who can't feed on their own. Omega-3s would be added to their IV solution.
"We want to give omega-3 right from the beginning to mimic what the infants would be getting from their mothers in utero, had they not been born prematurely," Smith notes in the news release.
That study is designed to test whether omega-3 fatty acids will help the babies develop healthy eyes, including the blood vessels in their eyes.