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)
less than 1 - You're okay. What you see is what you get.
1 to 50 - Ugly people starts to look unoffensive.
50 to 100 - Ugly people starts to look attractive.
above 100 - Ugly people starts to look like super models.
Here's my tip on how to use this formula - Constantly calculate your value. Once it hits 50, don't hit on anyone.
Of course, if your score is above 100, you might as well just resign to fate, because I don't think you'll have the ability to work out the formula.