That would be 1 liter of the active ingredient, not 1 liter of the eye drop. Also I don't believe that 1 ppt of this stuff is harmful when people are putting it directly in their eyes without severe harm.
Yes, but too slowly to matter. Average person consumes 1.5 liters per day of water, so if you live to 100 that's 55000 liters. At 1 ppt that's 1 ng / liter, or 55 ug over a lifetime. That's multiple orders of magnitude less than one drop of the stuff to your eye.
We will know after the drops have been out for over a decade, and actual real-world safety data studies get published.
Meanwhile, Restasis (cyclosporine A) (or a generic) works well, and doesn't have to be applied all day long, just two or three times a day. It does burn the eye initially, but it's not harmful, and the burning goes slowly away over time. It does take a few months to start working.
Maybe, maybe not, maybe like teflon, the real poison is an intermediate ingredient, but I think its bullshit that we're just creating chemicals that linger in our water supply for eternity. You literally cannot find anyone in America without traces of the dangerous variant of the PFAS in their blood stream. Like every sip of water is some ridiculous dupont cocktail and we have to tolerate it because people have dry eyes and want non stick pans. Why cant you just use theratears?
One thing you can be sure of is that the vats of PFAS being produced year after year for this drug aren't going away anytime soon. They're called "forever chemicals" for a reason.
Being dispersed in the environment is not the same as being concentrated into our drinking water supply with each measure resulting in 1ppt contamination of a trillion measures of water.
Largely firefighting foams, industrial and manufacturing, and landfill sources, but it's still an interesting problem. They don't really break down (that's why they're so useful both in a materials science sense and as a medication) which implies they'll stick around for an extremely long time.
