Caligo
From BiblePortal Wikipedia
Webster's Dictionary [1]
(n.) Dimness or obscurity of sight, dependent upon a speck on the cornea; also, the speck itself.
Cyclopedia of Biblical, Theological and Ecclesiastical Literature [2]
in Roman mythology, is darkness, the origin of all things, from which Chaos originated. By Chaos, Caligo was mother of night and day, Erebus and AEther.