The meaning of glaukos

Nordicists often use the Greek adjective glaukos, which was usually applied to eye color as evidence for the alleged presence of many blue-eyed individuals in ancient Greece. Thankfully, an entire book [1] has been written on the meaning of glaukos where all of the word's uses throughout Greek history (and even in Mycenaean Linear B) are recorded. It will be useful to quote Maxwell-Stuart's conclusion:

In sum therefore, glaukos and words derived from it were used mainly of the eye, especially of those eyes affected by glaucoma or cataract. Instinctive fear of blindness must be very strong among all sighted human beings, so their immediate reaction to such an eye will manifest itself in a repulsive frisson. Men will wish to ward off a similar fate from themselves. Healthy eyes of that colour therefore have something unnatural about them, and their relative infrequence in Greece proper (and, indeed, in Crete), will have aroused a similar instinctive hostility. Fear of the unknown and of the unusual would contribute to the notion that possessors of such eyes must be malign; hence the long association of blue and the Evil Eye which has lasted in Greece and the surrounding area until modern times. Not surprisingly, these feelings of hostility would be strengthened by knowledge that foreigners from the cold North - those dangerous, incursive, un-Greek people - had blue eyes, their intensity only the greater by frequent accompaniment of blond hair (we have noted often the close association of xanthos and glaukos).

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In other words, the intense emotional and symbolic power of glaukos stems almost entirely from its application to a certain type of eye which was felt to be maleficient, dangerous, and hostile and which Athene, alone of all the gods, possessed in her role of divine protectress, as it were a living amulet, of certain Homeric heroes in particular, and of Athenian craftsmen in general.

[1] Maxwell-Stuart, P. G. Studies in Greek colour terminology, vol.1 "Glaukos". Leiden : Brill, 1981