Brewer's: Itching of the Eye
If the right eye itches it betokens laughter at hand; if the left eye, it betokens grief; but Shakespeare does not observe this distinction.
My right eye itches now, so I shall see My love.
Theocritus, i. 37.
Mine eyes do itch; Doth that forebode weeping?
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894