These contact lens are the monthly wear ones. I have been using these since they first came onto the market several years ago. I have strong prescription -7.5 in both eyes. I work shifts so had found it really difficult to use conventional contact lens as I never seemed to get the hang of them especially with night shifts. I tried these and the first time in my adult life I woke up and could see things which let me tell you was a big wow. I have generally put these through their paces especially with working long nights shifts during which the best of eyes get tired an dry but i never had a problem. During the time i have used these i have also had knee surgery and with conventional lens you couldn't wear them but with these lens I was able to keep them in and hence felt less disoriented when i came round from surgery. I would say to get them from a good optician as then you can be check to see if they suit you.