The new studies aren't the strongest level of scientific evidence, but they confirm the findings of previous studies that also link fish consumption with prevention of macular degeneration.
A study of 681 elderly American men showed that those who ate fish twice a week had a 36 percent lower risk of macular degeneration. In the other study, which followed 2,335 Australian men and women over five years, people who ate fish just once a week reduced their risk by 40 percent.
Researchers don't know yet why eating fish seems to protect the eyes. Omega-3 fatty acids may neutralize free radicals in the eye, preventing the formation of new blood vessels, reducing inflammation or all three. Stronger evidence may come in five or six years with results from a large, randomized study of how fish oil and another nutrient, lutein, affect macular degeneration, according to the National Eye Institute. Volunteers will be assigned randomly to get either fish oil, lutein, or both -- or placebos.