EYESALVE

i'-sav (kollourion; collyrium; Revelation 3:18): A Phrygian powder mentioned by Galen, for which the medical school of Laodicea seems to have been famous (see Ramsay, The Letters to the Seven Churches of Asia), but the figurative reference is to the restoring of spiritual vision.

From the International Standard Bible Encyclopedia
Edited by James Orr, published in 1939 by Wm. B. Eerdmans Publishing Co.