My vision had actually improved over the last 2-3 years which I can confidently attribute to my change in diet (Vegan) since two years ago and the products I consume. I went from 20/40 vision and wearing nighttime glasses and reading glasses to 20/20 or better with no prescription for any glasses or contacts or reading glasses. However, due to some dry eye issues I have dealt with for years, my Ophthalmologist recommended I use Systane, which includes as it's active ingredient Propylene Glycol @ roughly 6% (if I recall correctly).
Please check out the link I've provided for the Material Safety Data Sheet concerning Propylene Glycol and the direct information below regarding its other toxic effects on humans...I think I'll pass Doc!
This is just another example of our Healthcare system needing to be renamed Sickcare!