| 摘要 |
PURPOSE: To enable a lens device to be securely worn by providing a flange which extends radially outwards from an optical element with two radially extending projections, locating a part of each projection on the same side with respect to the optical axis of the optical element within the same radial plane, and extending one of the projections radially outwards. CONSTITUTION: A lens device has an optical element 14 and a flange 16 extending radially from the optical element, the flange 16 including a first rear face 32, a second front face 26, a third surface 30 adjacent to the first rear face 32 along the direction away from the optical element 14, and a fourth surface 28 adjacent to the second front face 26 along the direction away from the optical element 14. The third and fourth surfaces 30, 28 form an almost V-shaped groove which extends outward as a whole from the radial axis 18 of the lens device. When a lens is worn on the cornea, both the third surface 30 and the second front face 26 of the flange 16 overlap with the corneal tissue to allow secure wearing, with the V-shaped groove filled with the corneal tissue to set the lens firmly in a predetermined position on the cornea. |
