I was diagnosed with navicular accessory syndrome and have extremely flat feet. My physical therapist recommended Birkenstocks and boy am I glad he did. I was in constant pain and walked with a limp for almost a year after what turned out to be a very minor strain to the muscle in my inner foot. When I finally forced myself to see a physician, they enlightened me to what a horrible over pronator I am, meaning I walk on the inside of my feet. I also do this when I run, explaining my shin splints. These shoes have worked wonders for me. I ordered this particular pair because they match everything I own and this is a lot of money for shoes. Initially, I hated them, but after some research I learned that these take a couple weeks of getting used to because of the 0 to 60 effect they have on your arches. Now I wouldn't give them up for anything. They have basically corrected how I walk so even when I'm barefoot in the house I'm no longer over pronating. I could sleep in these they're so comfy!