Origins Of The Evil Eye
Throughout the ages, lyrics have been written and songs have been sung for beautiful eyes, the Greeks believe that these very beautiful eyes become the harbingers of misfortune and doom when they turn towards you with greed and envy. This belief rests not only in Greece, but also among all the people of the Mediterranean countries as well as in the Indian sub-continent and the legends of Mexico. The Evil Eye belief says that when someone eyes your good fortune with jealousy or gluttony, bad luck in some form is bound to befall you.
The amount of literary and archeological evidence attests to the belief in the evil eye in the eastern Mediterranean for millennia starting with Hesiod, Callimachus, Plato, Diodorus Siculus, Theocritus, Plutarch, Heliodorus, Pliny the Elder, and Aulus Gellius. In Peter Walcot's Envy and the Greeks (1978) he referenced more than one hundred of these authors' works related to the evil eye. Studying these written sources in order to write on the evil eye only gives a fragmented view of the subject whether it presents a folkloric, theological, classical, or anthropological approach to the evil eye. While these different approaches tend to reference similar sources each presents a different yet similar usage of the evil eye, that the fear of the evil eye is based on the belief that certain people have eyes whose glance has the power to injure or even kill and that it can be intentional or unintentional.  Classical antiquity
Roman-era mosaic from Antioch depicting a plethora of devices against the evil eye
Belief in the evil eye during antiquity is based on the evidence in ancient sources like Aristophanes, Athenaeus, Plutarch, and Heliodorus. There are also speculations that claim[who?] Socrates possessed the evil eye and that his disciples and admirers were fascinated by Socrates' insistently glaring eyes. His followers were called Blepedaimones, which translates into "demon look," not because they were possessors and transmitters of the evil eye, but because they were suspected of being under the hypnotic and dangerous spell of Socrates.
In the Greco-Roman period a scientific explanation of the evil eye was common. Plutarch's scientific explanation stated that the eyes were the chief, if not sole, source of the deadly rays that were supposed to spring up like poisoned darts from the inner recesses of a person possessing the evil eye (Quaest.Conv. 5.7.2-3=Mor.80F-81f). Plutarch treated the phenomenon of the evil eye as something seemingly inexplicable that is a source of wonder and cause of incredulity.
The belief in the evil eye during antiquity varied from different regions and periods. The evil eye was not feared with equal intensity in every corner of the Roman Empire. There were places in which people felt more conscious of the danger of the evil eye. In the Roman days not only were individuals considered to possess the power of the evil eye but whole tribes, especially those of Pontus and Scythia, were believed to be transmitters of the evil eye. The phallic charm called fascinum in Latin, from the verb fascinare, "to cast a spell" (the origin of the English word "fascinate"), was used against the evil eye.
The spreading in the belief of the evil eye towards the east is believed to have been propagated by the Empire of Alexander the Great, which spread this and other Greek ideas across his empire.  Distribution of the belief
Tree with nazars in Cappadocia, Turkey.
Belief in the evil eye is strongest in the Middle East, East and West Africa, Central America, South Asia, Central Asia, and Europe, especially the Mediterranean region; it has also spread to other areas, including northern Europe, particularly in the Celtic regions, and the Americas, where it was brought by European colonists and Middle Eastern immigrants.
Belief in the evil eye is found in Islamic doctrine, based upon the statement of Muhammad, "The influence of an evil eye is a fact..." [Sahih Muslim, Book 26, Number 5427]. Authentic practices of warding off the evil eye are also commonly practiced by Muslims: rather than directly expressing appreciation of, for example, a child's beauty, it is customary to say Masha'Allah, that is, "God has willed it," or invoking God's blessings upon the object or person that is being admired. Aside from beliefs based upon authentic Islamic texts, a number of unsubstantiated beliefs about the evil eye are found in folk religion, typically revolving around the use of amulets or talismans as a means of protection.
Although the concept of cursing by staring or gazing is largely absent in East Asian and Southeast Asian societies, the Usog curse of the Philippines is an exception.
In the Aegean Region and other areas where light-colored eyes are relatively rare, people with green eyes are thought to bestow the curse, intentionally or unintentionally. This belief may have arisen because people from cultures not used to the evil eye, such as Northern Europe, are likely to transgress local customs against staring or praising the beauty of children. Thus, in Greece and Turkey amulets against the evil eye take the form of blue eyes, and in the painting by John Phillip, below, we witness the culture-clash experienced by a woman who suspects that the artist's gaze implies that he is looking at her with the evil eye.
Among those who do not take the evil eye literally, either by reason of the culture in which they were raised or because they simply do not believe in such things, the phrase, "to give someone the evil eye" usually means simply to glare at the person in anger or disgust.