i just dont trust any product off the shelf to put in my eyes. i have put lots of CS in my eyes and i used a dropper full strength. it is quite safe and also a strong sensation sometimes, though i wouldnt call it pain and it doesnt last long. i wasnt looking for any benefit in particular and i dont recall any specific reaction other than the impression that the eyes are under continual environmental stress and perhaps biological too. if you are making your own and trust what is in it, i say go for it.