Most myodisc glasses have lenses with plano fronts or in extreme cases, concave fronts. Here the fronts of the lenses have a convex shape. The strong cylinders are not just included in the bowl but in the carrier lens as well. The back side of the bowl only has the strong curve corresponding with the extreme spherical values needed by the first owner of the glasses. I have never seen this in any other pair of myodisc glasses.