What's the probability that having speck in the eye at any given time has some terrible consequences (like, for instance, causing traffic accident, or making a mistake when doing a brain surgery)? If we assume that on the whole Earth, at any time there's at least one person who would suffer greatly from speck in the eye, the probability is at least 1/8e9.
Now notice that 1/8e9 of 3^^^3 is more people than have ever lived.
I assumed there to be no side effects to the dust specks. Otherwise millions would die in accidents and the thought experiment wouldn't make much sense.
Now notice that 1/8e9 of 3^^^3 is more people than have ever lived.