Clearly, ancient Egyptians didn't get the memo about lead poisoning. Their eye makeup was full of the stuff. Although today we know that lead can cause brain damage and miscarriages, the Egyptians believed that lead-based cosmetics protected against eye diseases. Now, new research suggests that they may have been on to something.
The following is a little more information about the science behind this discovery, from Chemical Online: Ancient Egyptian Cosmetics - Magical Makeup May Have Been Medicine For Eye Disease
Here is another source reporting on the same story on January 18th: Ancient Egypt's Toxic Makeup Fought Infection, by Sindya Bhanoo - NY Times