Barb, I have had dry eyes for years and my Opthamologist recommended Refresh plus too. I'll probably hear from some people that this is a dangerous practice, but for years, when I open one of the little vials in the morning, I save it and use the unused portion at night. I also keep the regular Refresh on hand(it also comes in little vials and has no preservative) I use it the same way and save the expensive stuff for "Bad Eye" days. Maybe this would work for you too. Good luck, Barbara Smith,CG/Ken/70/17