These designer prescription glasses are made to accommodate most prescription lenses.Made of Other.Sferoflex Rita (SF 570U) frames have a round shape, which helps to balance rectangular facial features. Frame shape is the most noticeable feature of a pair of glasses, followed by frame color and frame size. Top brands always have a large collection of rectangle frame shape glasses, as well as oval frame shape glasses.Sferoflex Rita (SF 570U) frames feature a fashionable full frame design, which is the largest component of designer eyeglasses brands collections. A rim all the way around the lenses, provides for maximum stability and durability.The frame has a Universal.Designed for adults, this model has a Spring type hinge for greater comfort.Standard skull temples can be easily adjusted to fit perfectly behind your ears. See all Sferoflex Sferoflex Eyeglasses Sferoflex Glasses: Sferoflex is the name of the eyeglasses line characterized by a spring temple invented and patented by Sferoflex glasses in 1941. Many years have gone by since Luxottica Group took over Sferoflex (in 1982), yet the Sferoflex glasses are manufactured still today in the very same plant located in Rovereto, Italy, where they were originally born. The very name Sferoflex indicates the main feature of these glasses: the flex temple. A special spring mechanism inside the hinge makes the temples flexible and allows the glasses to adapt to the size of every face without causing any annoying constraints, and thus providing an extremely comfortable fit.