| 摘要 |
A contact lens is provided for the eye of a patient with a cornea having a central surface. The contact lens includes a posterior surface which includes an innermost or generally flat circular first zone having a diameter which is at least 0.5 mm greater than the greatest dimension of the central corneal surface. The radius of curvature of the first posterior surface is at least as small as that of the central corneal surface. A generally annular second posterior zone extends radially beyond the first zone, the second zone having a radius of curvature less than the radius of curvature of the first posterior zone and generally corresponding to the curvature of the corneal surface surrounding the central corneal surface. In one embodiment, a generally annular third peripheral zone preferably extends radially beyond the second zone and outwardly from the corneal surface to facilitate circulation of fluid between the contact lens and the cornea. The anterior surface of the lens includes a first generally circular corrective zone for correcting the patient's vision and a second generally annular zone extending radially beyond the corrective zone and generally paralleling the second posterior zone.
|
