Schaff's Bible Dictionary
EYES. It was part of the cruelty which distinguished ancient warfare to put out the eyes of prisoners, particularly those who were prominent or dangerous. This custom is referred to in Jud 16:21; 1 Sam 11:2; 2 Kgs 25:7. , 2 Kgs 9:30; Jer 4:30; Eze 23:40, and prevails extensively now among Eastern women, especially among Mohammedans. The hair and edges of the eyelids are tinged with a fine black powder moistened with oil or vinegar, which causes a small black line to appear around the edge, and at a distance (and especially by candlelight) gives a heavy, dark shade to the eyes.
A smooth cylindrical piece of silver or ivory, shaped like a quill and about 2 inches long, is dipped into the composition and placed within the eyelashes, which are closed over it. The figurative use of the word "eye" to indicate alacrity and vigilance occurs Eze 1:18; Eze 10:12; Rev 4:6, Rev 4:8.