Alcohol is a drying agent, which causes drying of the eyes, with decreased tears and inflammation of the mucous membranes of the eyelid. Even without contact lenses, many people feel their eyes are irritated the morning after drinking (the classic "red eyes" of hangover). It is known that solvent vapors can be absorbed into soft contact lenses in the work place, so it is possible that the lenses themselves can absorb alcohol, though there is nothing in the contact lens literature that advises about that happening from drinking alcohol (presuming the alcohol level in tears is negligible) but rather the warning comes in laboratory/industrial workers exposed to solvent fumes.