They are very expensive compared to normal lenses. £40 a month. They work very differently to glasses in that you don't have to train your eye to look in a certain direction. The optician did explain it to me and from what I can remember each contact lens is made up of a 'honeycomb' consisting...
I mainly wear contact lenses which are varifocal and have a pair of varifocal glasses. Both are great but they take time getting used to. The glasses in particular took a few weeks they caused a dizzy kind of effect when looking down- avoid patterned carpets!