How do opticians put lenses in glasses?
Lenses are supposed to be cut to fit the exact measurements of the frames. Then they unscrew the sides put the lens in, close the frames and screw them back together. Some frames don’t work that way and the lenses are cut with a slight groove around them and pop in the frames. The groove is supposed to help prevent the lenses from popping back out easily. If they have screwed up twice already you may want to have a different optical center make your glasses.
