In order to keep the evil eye away, we wear jewelry with blue, glass eyes or have them hanging from a wall or something. It takes away the bad energy that somebody else could be giving you.
My mother first introduced me to this idea and she said that it is very popular in old cultures. Everybody in Iran, and in most other cultures, have theories of the evil eye and how to keep it away. This was not something somebody taught my mother; rather, it is something she grew up with. Many people think that the evil eye is a superstition whereas some other people believe in it. In order to keep the evil eye and bad energy away, my mom put blue, glass eyes all over our house. For example, if somebody pays a compliment, he or she may be sending bad energy by through jinxes, intentionally or even unintentionally.
Belief in the evil eye is routed back to the Muslim religion and the Koran. It is very popular in Middle Eastern countries, the Mediterranean area, and some parts of Asia. Everybody in my family, including me, believes in this tradition. I always wear this bracelet my mom gave me when I was very young. It is gold and has three blue, glass eyes on it. Whenever I am not wearing it, I feel uncomfortable that something bad will happen. For example, when my dog died a couple of years ago, my mom and my aunts believed that somebody gave him the eye. They did not believe that was the reason that caused his death because he was already very old, but they did believe it had a part to do with it. After that incident, she told me to wear the bracelet she gave me all the time and even gave me a glass eye to hang on the rear view window of my car.
My mom also has other precautions of keeping the bad energy away. Other than the glass eyes, she also knocks on wood and also burns seeds of esfand (or aspand) on charcoal so that the smoke can waft through the house. I know that these all count as superstitions but I do believe that they have some sort of power. It may just be a sense of comfort and security but it is a theory that dates back many years and has become a custom and tradition.