Webster's Revised Unabridged Dictionary · 1913

Wall-eyed , adjective

[Icelandic valdeyger, or vagleygr; from vagl a beam, a beam in the eye (akin to Swedish vagel a roost, a perch, a sty in the eye) + eygr having eyes (from auga eye). See Eye.]

Shakespeare, in using wall-eyed as a term of reproach (as “wall-eyed rage,” a “wall-eyed wretch”), alludes probably to the idea of unnatural or distorted vision. See the Note under Wall-eye. It is an eye which is utterly and incurably perverted, an eye that knows no pity.