From BiblePortal Wikipedia

People's Dictionary of the Bible [1]

Eyes. The practice of putting out the eyes as a mode of punishment has been in both ancient and modern times very common in the East. Captives in war, and those who might be supposed likely to head rebellions against the sovereign were frequently thus treated.  Judges 16:21;  1 Samuel 11:2;  2 Kings 25:7. The painting of the eye was and is usual among Eastern women. This was what Jezebel did,  2 Kings 9:30, marg., R. V. "painted her eyes;" comp.  Jeremiah 4:30;  Ezekiel 23:40. A peculiar brilliancy is imparted to the eye, and a languishing, amorous cast given to the whole countenance. The eyelids and eyebrows are thus painted with what is called kŏhl . "The powder from which kŏhl is made is collected from burning almond-shells, or frankincense, and is intensely black. Antimony and various ores of lead are also employed. The powder is kept in vials or pots, which are often disposed in a handsomely worked cover or case; and It is applied to the eye by a small probe of wood, ivory or silver, which is called meet, while the whole apparatus is named mîkhûly ."

Morrish Bible Dictionary [2]

Used symbolically for the omnipresence of God. "The eyes of the Lord are in every place,"  Proverbs 15:3; "the eyes of the Lord are upon the righteous."  Psalm 34:15;  1 Peter 3:12 : cf.  2 Chronicles 16:9;  Zechariah 4:10 . His eyes are also upon the wicked, and His eyes will not spare, neither will He have compassion in the day of judgement.  Ezekiel 5:11 . The eye is also used symbolically for the organ that transmits the light to the soul.If the eye is single — there being but one object (the glory of God) before the soul — the whole body is full of light; but if the eye be evil, having divers objects (as when an eye sees double), the whole body is full of darkness. And if the light (true light it may be) be darkness, how great is that darkness! A Christian in this condition may do the very things he had strongly condemned in others.  Matthew 6:22,23;  Luke 11:34-36 .