This year, an estimated 1.5 million nearsighted Americans will trust their eyes to laser-wielding surgeons. While the so-called LASIK (laser-assisted in-situ keratomileusis) procedure carries risks, many will toss their glasses and give thanks to their doctors. What they don't know is that a leftover Thanksgiving turkey deserves credit too.

Just a few years after the 1960 invention of the laser, doctors began to use the new tool in eye surgeries, burning off tumors, for example, or "welding" torn retinas back together. But the technology of the 1960s and 1970s wouldn't have allowed surgeons to operate on the cornea-the clear front portion of the eye whose curvature helps determine whether a person is nearsighted, farsighted or has eagle eyes-because the colors of laser light available at the time passed right through clear materials without doing anything to them. What's more, because the first-generation lasers worked by heating tissue, they left scars.