Could someone please explain the difference between the Physio and Physio360. I've been to Varilux.Com, but they are far from clear on the target market of either product. I know the following question has been asked and answered in many posts, but I am getting ready to make a purchase and just want to be sure (the retailers tell me the opposite of what I read here)... For a light prescription using a Varilux lens and a regular metal frame, I am better off getting a standard plastic lens as opposed to a polycarb lens... is that generally correct? Thanks Tom