The third eye refers to your sixth chakra. It's an energy gate located in the general area of your forehead. It's referenced on this site frequently since many people associate it with psychic abilities.
The evil eye is a magical "power" in folklore and folk medicine in many eastern european and middle eastern countries. According to belief, some people have the ability to pass this evil eye onto others, like an unintentional curse, usually in jelousy or envy. Symptoms include wasting away, sudden illness, and colic in babies.
For more on the evil eye:
ok now i know you folks are gonna wanna slap me for this one but in the movie sleepy hollow (with jhonby depp) when they found the "evil eye" under his bed was that the acurate symbol or just hollywoods own interpatation