Description Optical Lens & Frame The corrective lenses with Universal Optical Frame are for all TUSA Sport masks with single lens. Meaning that the mask is not divided in two lenses, but is a one lens mask as shown in the picture below. Available with a frame and pair of same diopter lenses -2.0, -3.0, -4.0, -5.0. Both eyes will have the same correction diopter. Masks shown in the pictures are not included.