I started using this a few years ago when I was having issues with my contacts having smudgy looking spots on them. My regular contact solution wasnt cutting it anymore and was causing some issues. My doctor suggested I switch to this and it has helped. I gave it 4 stars because it is a little pricier but it does last a while so that helps. It also burns my eyes every now and then (even though I wait longer than the 6 hour minimum). But over all its a good product and helps keep my contacts clean.