For sure, I know all that. And I will be arguing in my publications that EIS is 
different. Obviously risk or argyria is low. But not zero. It's the very rare 
events that I need to follow up on and characterize. Not the people who have 
had no problems. 
And as Jason has noted, sliver sludge and floaters are trojan horses for 
uncontrolled doses of silver, which - depending on a persons process - could 
conceivably contribute to argyria, even if we are talking about EIS. 
David