Hi @drcynthia. I had PRK done on my eyes about 2 years ago (really happy with the results) but I was recommended use of Systane and Refresh eyedrops for my dry eyes. I noticed the same thing you are talking about, after a while I kept needing them more and more and it wasn't as effective. Eventually I stopped using them and it worked out, my eyes went back to normal about a year later but I think it's not just Visine that has that issue.