Method for designing an anterior curve of a contact lens
View Patent ↗In accordance with the disclosure there is described herein a method of designing an anterior curve of a contact lens for the eye of a patient comprising the steps of providing a contact lens material having a posterior, a posterior curve having a predetermined asphericity, an anterior, an index of refraction and a center thickness; providing a geometry of a cornea, a distance power correction for the cornea and a near power correction for the cornea; determining a central distance power of the contact lens in air; calculating a central anterior radius of the contact lens using the posterior curve of the contact lens material, the index of refraction of the contact lens material, the center thickness of the contact lens material and the central distance power of the contact lens in air; calculating a center power of the contact lens on the eye of the patient using the index of refraction of tears at the posterior of the contact lens; and using an on-eye ray trace, said on-eye ray trace having a null lens compensation to create a targeted on-eye power profile.
1. A method of designing an anterior curve of a contact lens for the eye of a patient comprising the steps of:
providing a contact lens material having a posterior, a posterior curve having a predetermined asphericity, an anterior, an index of refraction and a center thickness;
providing a geometry of a cornea, a distance power correction for the cornea and a near power correction for the cornea;
determining a central distance power of the contact lens in air;
calculating a central anterior radius of the contact lens using the posterior curve of the contact lens material, the index of refraction of the contact lens material, the center thickness of the contact lens material and the central distance power of the contact lens in air;
calculating a center power of the contact lens on the eye of the patient using the index of refraction of tears at the posterior of the contact lens; and
using an on-eye ray trace, said on-eye ray trace having a null lens compensation to create a targeted on-eye power profile.
2. The method of designing an anterior curve of a contact lens according to claim 1 further comprising providing a curvature of the null lens, the curvature of the null lens is set to a flat curvature of the eye of the patient whereby the null lens is used to compensate for the spherical aberration correction of the eye of the patient.
3. The method of designing an anterior curve of a contact lens according to claim 1 wherein the posterior curve of the contact lens material is used to adjust the centering of the contact lens on the eye of the patient.
4. The method of designing an anterior curve of a contact lens according to claim 1 wherein the posterior curve of the contact lens material is used to adjust the movement of the contact lens on the eye of the patient.
5. The method of designing an anterior curve of a contact lens according to claim 1 further comprising providing a contact lens diameter, the contact lens diameter is adjusted to center the contact lens on the eye of the patient.
6. The method of designing an anterior curve of a contact lens according to claim 1 further comprising providing a contact lens diameter, the contact lens diameter is adjusted to provide the proper movement of the contact lens on the eye of the patient.
7. The method of designing an anterior curve of a contact lens according to claim 1 wherein the targeted on-eye power profile is adjusted to provide proper distance power and proper near power.
8. The method of designing an anterior curve of a contact lens according to claim 1 wherein the targeted on-eye power profile is adjusted to improve distance visual acuity.
9. The method of designing an anterior curve of a contact lens according to claim 1 wherein the targeted on-eye power profile is adjusted to improve near visual acuity.