vintage eyeglasses in case unusual black rims (no temples) in old case unbranded

See pictures of these unusual eyeglass lenses. they are made of a hard plastic, i believe. they are flat except for the bridge. i don't have any information about them. i think they are basically for magnification. case appears to be very old and i cannot say if these originally came together. thanks for viewing my item. (if you can enlighten me about this style, i'd appreciate it.)