The blind drunk stage is a later stage of drunkenness that usually precedes the stage of passing out. People often arrive at the passing-out stage without experiencing the blind drunk stage at all.
Controlled scientific tests might, conceivably, show this to be related to fatigue - a fatigued person would succumb to alcohol and pass out before arriving at the blind drunk stage. On the other hand, such tests might also draw a connection between alcohol tolerance and the ability to become incoherent and visually impaired without first becoming unconscious.
Consequently, blind drunkenness might be a state reserved for those who are well-rested, or it might be a state related to alcohol tolerance.