In addition to having heart benefits, fish may be good for your eyes. Several large observational studies have linked fish intake—in particular, fish rich in omega-3 fats—to reduced AMD incidence and progression, and possibly to reduced risk of cataracts. A 2011 study in Archives of Ophthalmology found that women who consumed the most omega-3s from fish were 40 percent less likely to develop AMD than those with the lowest intake.
If you have type 2 diabetes, eating fatty fish may reduce the risk of diabetic retinopathy, a complication of diabetes that often causes blindness. An analysis of data from the Spanish PREDIMED study, designed to evaluate the potential benefits of the Mediterranean diet, reported these findings in 2016 in JAMA Ophthalmology.
That analysis focused on 3,400 participants (average age 67) who had type 2 diabetes, correlating their intake of omega-3 fats from seafood with their risk of diabetic retinopathy over a six-year period. Those consuming at least 500 milligrams of marine omega-3 fats a day, on average—equal to about two or three servings of fatty fish a week—were 50 percent less likely to develop retinopathy than those consuming less than that.
Fish high in omega-3s might also help counter dry eye syndrome. A 2005 study of more than 32,000 women, published in the American Journal of Clinical Nutrition, found those who consumed the most omega-3 fats from fish had a 17 percent lower risk of dry eye, compared with women who ate little or no seafood.
The American Academy of Ophthalmology says that omega-3 fats appear to improve function in the eye's meibomian glands, which produce the oily part of tears. Improved function of those glands can ease dry eye symptoms. The omega-3s in fatty fish are also believed to reduce inflammation, and inflammation of the eyelids or surfaces of the eye worsens dry eye.