1. Chlorine isn't used anymore, it's dishonest to claim that it is just as it's dishonest to claim peracetic acid is dangerous or ends up in the end product.

2. Well aware of the problems and concerns with the supply chain in the US, but not treating and dealing with salmonella outbreaks would have measurably worse health outcomes. These problems don't get fixed overnight. I'm fine with those problems being attacked but don't spread FUD about what you don't understand.

So the thing you need to know is there's 2 categories of soft contacts that are currently on the market. Hydrogels and Silicone Hydrogels (SiHy). The latter are newer and have become much more common as they are in theory healthier for the eye (they allow more oxygen to pass through). There's some drawbacks though in that the material isn't inherently wettable because silicone is hydrophobic by nature. This means it's a bit more complex to formulate a material and there's some quirks to it, notably it's usually stiffer. This might affect how solutions interact with the surface.

Corneal staining is basically scratching of the outer part of your eye. It is usually asymptomatic but can result in a burning sensation. It was found that the surface of SiHy is affected by what material is used to clean them. This link includes some research and plenty of linked studies: https://contactlensupdate.com/2013/08/14/what-do-we-know-abo... I had a better link that compared various products on the market but I'm unable to find it as this time.