Corneal-sclera orthokeratology lens with asymetric blends
A corneal-scleral orthokeratology contact lens is formed of rigid gas permeable material with uniform arc lengths in the treatment area even when the corneal curvature varies and asymmetric blends or splines called minor zones, where the portion of the blend or spline is shorter toward the lens center and broader toward the lens edge, and relieve the treatment area of all centering responsibility, transferring it to the limbal-scleral region. The method of determining the total sagittal height of an eye at a given chord diameter to predetermine exact fitting parameters and predict unaided visual outcome trial lenses, with exact chord and sagittal height values used to match the sagittal height of an eye, the sagittal value may be obtained from some ocular topographers. A computer program can easily take the sagittal information and design an optimum lens.
1. A rigid gas permeable corneal-scleral orthokeratology contact lens having a center and a posterior surface, the lens for an eye, said comprising: lens major ocular zones on the posterior surface of the lens; comprising: minor zones which are asymmetric blends located between the major ocular zones and connecting the major ocular zones of the lens where the width of the inward most portion of each asymmetrical blend, nearer the center of the lens is less wide than the outward portion of each blend further from the center of the lens.
2. The invention in accordance with claim 1 wherein the corneal-scleral orthokeratology contact lens comprises;
a first edge zone being an outermost edge zone to align with a small portion of the sclera and the limbus to center the lens; a second major edge zone having an inward curve controlling the overall sagittal height of the lens; and
a third major edge zone vaulting the peripheral cornea.
3. A rigid gas permeable corneal-scleral orthokeratology contact lens for an eye, said lens having major curves including a central posterior treatment surface (base curve), a second portion extending over the peripheral cornea, limbus and a portion of the scleral surface of the eye, the lens further comprising:
minor zones which are asymmetric blends connecting the major curves of the lens, the minor zone of an asymmetric blend including an outward portion of the blend and an inward most portion of a blend; and
the width of the inward most portion of the blend is less wide than the width of the outward portion of the blend.