Tear-free Shampoo

So Ive heard and read several times that the reason some soaps and shampoos are "tear free" is because a chemical is added to them that actually numbs the eye when it comes in contact with it. This is obviously alarming. When I researched it I found other articles (from sites like Johson & Johnson) that say its a PH thing - getting it at just the right PH means it doesnt sting?

I found this, which seems to make sense:

"PH of hair and skin of humans is 4.5 to 5.5.PH of eyes is 7.By making the PH of the shampoo the same as the eyes, it doesn't causeas much stinging and tearing. It does however, dry out the hair and scalp."

Here is a store selling a tear-free shampoo that they say is tear-free because of a ph of 6.5 but they do claim that other companies use a tear-supressing chemical in their tear-free products. So maybe its both??? or maybe its just a big internet myth?

J&J didnt score well for any products on the EWC site - click here. But there are much healthier options for shampoos (click here) like Ca Baby and even Huggies shampoo (shockingly) got an "ok" score.

If anyone knows if there really is a chemical used in some of these tear-free shampoos Id love to see some proof!