My sister has lymphedema.  I purchased these because of her feet swelling.  She usually wears a 10/11, but I got these in 12 because her feet can swell pretty huge.  Come to find out, the 12 was way too big.  So I traded for a size 10 and we'll find out how that goes. She says they are very comfy and don't irritate her feet, nor compresses the swelling too much.