You'll see the egg white turn cloudy, then white, as normally clear proteins in the egg are irreversibly altered by the heat. Well, something similar to that happens when you get cataracts. Proteins in the lens of the eye lose their crystal-clear properties, becoming yellowish, cloudy and about as easy to see through as a fried egg. Of course, cataracts take not seconds but many years to form. Many doctors now think that the main cause of cataracts is oxidative damage to cells in the eye's lens.
Oxidative damage is the same chemical process that rusts iron and makes cooking oil turn rancid.
In the lens, the oxidative process can occur as part of normal metabolism as well as in the presence of light, which creates harmful unstable molecules called free radicals. The lens can partially protect itself from this free radical damage, and it relies on certain nutrients to keep its defense system strong. Even B vitamins such as riboflavin and B 12 as well as an amino acid called cysteine may be involved, but evidence for these nutrients is very slim, says Randall Olson, M.D., professor and chairman of the Department of Ophthalmology at the University of Utah School of Medicine and director of the John A. Moran Eye Center, both in Salt Lake City. And the evidence seems to indicate that these nutrients are synergistic, that they work best together. And a study by Canadian researchers found that supplements reduced cataract formation by about 40 percent.