Schir haSchirim 5:12 Kabbala: Idra Zuta

That brain, that is, concealed Chochmah of Arich Anpin, is engraved at a time of immaturity, and shines during maturity with the three white hues of the eye (as said in the Greater Gathering of Naso, section 42; study there). They are the three types of Chesed in their three columns. With one type of white, they wash the eyes of Zeir Anpin, as written, “washed with milk” (Shir Hashirim 5:12), which is Chesed that is called milk, the first white of the three types of white in the eyes of Arich Anpin, that is, their right column. The other types of white wash and shine with the other luminaries, that is, the other levels.

The eyes of Zeir Anpin
The eyes in the head of Zeir Anpin are eyes that the wicked do not beware. They are eyes that are asleep yet not asleep, that is, at times they are asleep and at times they do not. They are therefore called, “His eyes are like doves (yonim)” (Shir Hashirim 5:12), yonim as in the verse, “you shall not defraud (tonu) one another” (Vayikra 25:14). This refers to price gouging; to the wicked they seem asleep, that is, not paying attention to the world. Hence it is written, “Yet they say, Yah shall not see, nor shall the Elohim of Yaakov regard it” (Tehillim 94:7) and “He that planted the ear, shall he not hear?” (Ibid. 9).