Just did a quick search and it does seem polyquad is a good safe preservative. What's annoying is it's in glaucoma drops outside the US, while most here use BAK. Like why can't the companies just do a quick trial using a different preservative and just reformulate it with that one change? BAK honestly should not be in any eye drops since safer and just as effective alternative preservatives exist. Even more bs is Travaton brand uses Sofvia, but the generic uses BAK. One is 300 bucks, one is 10. Such damn bs.