This story from Central America is particularly gruesome.
> In early April, an unfortunate British soldier walked into a snake that was hanging from a branch. It bit him in the eye. ‘He felt such intense pain’, a physician noted, ‘that he was unable to proceed’. Though the man’s comrades attempted to suck the venom from him, the man died ‘with all the symptoms of putrefaction’: bloated, skin coloured yellow, his eye dissolved.
I can't imagine trying to suck venom from someone's eye.