Scientists at Manchester University have actually developed a forumula which calculates the impact of alcohol on occular perception. (Note to Mom: also known as "Beer Goggles", the effect studies is the effect that more beer makes people more beautiful. I've never heard of it, I swear). The research, commissioned by eyecare firm Bausch * Lomb PureVision, included a number of other factors, including the smokiness of the room, luminance of the 'person of interest', visual acuity, and distance. A rating of less than one = no effect. Between one and 50, the person will appear more attractive, and above 50, a non-appealing person will look like a super model.
Note the following refers to the formula image:
An = number of units of alcohol consumed
S = smokiness of the room (graded from 0-10, where 0 clear air; 10 extremely smoky)
L = luminance of 'person of interest' (candelas per square metre; typically 1 pitch black; 150 as seen in normal room lighting)
Vo = Snellen visual acuity (6/6 normal; 6/12 just meets driving standard)
d = distance from 'person of interest' (metres; 0.5 to 3 metres)