| 摘要 |
A toric contact lens having a prism ballast structure, wherein a center optical area, an annular transition area surrounding the center optical area determining a refractive degree, and an annular peripheral area surrounding the transition area, are defined on a lens front surface. A shape of the lens front surface has a mirror symmetry with a vertical meridian as a boundary, in such a manner that a thickness is smoothly decreased toward a lens lower end portion from two maximum thickness portions and where the thickness of the lens is maximum, and a valley-shaped slab-off is formed between these maximum thickness portions. |
