Ophthalmic lens element
An ophthalmic lens element is disclosed. The lens element includes a front surface and a rear surface, at least one which includes a horizontal meridian and a vertical meridian. A central region of the lens element includes a foveal vision zone providing a first power for providing clear foveal vision for a wearer. A peripheral region of positive power relative to the first power is also included. The peripheral region includes dual progressive zones located bilaterally of the vertical meridian and extending radially outwardly from the central region. The lens element provides a distribution of surface astigmatism which provides, on the horizontal meridian, a relatively low surface astigmatism in the central region and the progressive zones.
1. An ophthalmic lens element including a front surface and a rear surface, at least one of the surfaces including a horizontal meridian and a vertical meridian, the lens element including:
a central region including a foveal vision zone providing a first power for providing clear foveal vision for a wearer; and
a peripheral region of positive power relative to the first power, the peripheral region including dual progressive zones located bilaterally of the vertical meridian and extending radially outwardly from the central region;
wherein the lens element provides a distribution of surface astigmatism which provides, on the horizontal meridian, a relatively low surface astigmatism in the central region and the progressive zones.
2. An ophthalmic lens element according to claim 1 wherein each progressive zone provides a mean power profile along a respective horizontal semi-meridian that provides a positive power gradient over a range defined by r a ≦r x ≦r b in which r a and r b are radial distances along each horizontal semi-meridian from the optical centre of the lens.
3. An ophthalmic lens element according to claim 1 wherein the first power is a prescribed power for providing an optical correction corresponding to a wearer's on-axis distance vision viewing requirements.
4. An ophthalmic lens element according to claim 1 wherein the positive power in the progressive zones provides an optical correction for retarding or arresting myopia associated with a peripheral region of the retina along the horizontal meridian of the wearer's eye.
5. An ophthalmic lens element according to a claim 2 wherein the range defined by r a ≦r x ≦r b is substantially 10 mm≦r x ≦22 mm.
6. An ophthalmic lens element according to claim 2 wherein the positive gradient over the range r a ≦r x ≦r b provides a positive mean power increase of at least 1.00 D relative to the refracting power at the optical centre of the lens element.
7. An ophthalmic lens element according to claim 2 wherein the positive gradient over the range r a ≦r x ≦r b provides a positive mean power increase of at least 1.50 D relative to the refracting power at the optical centre of the lens element.
8. An ophthalmic lens element according to claim 2 wherein the positive gradient over the range r a ≦r x ≦r b provides a positive mean power increase of at least 2.00 D relative to the refracting power at the optical centre of the lens element.
9. An ophthalmic lens element according to claim 2 wherein the positive gradient over the range r a ≦r x ≦r b provides a positive mean power increase of at least 2.50 D relative to the refracting power at the optical centre of the lens element.
10. An ophthalmic lens element according to claim 2 wherein the positive gradient over the range r a ≦r x ≦r b provides a positive mean power increase of at least 3.00 D relative to the refracting power at the optical centre of the lens element.
11. An ophthalmic lens element according to claim 2 wherein r a corresponds with a boundary between the foveal vision zone and the progressive zones defined by a +0.25 D contour of mean surface power on the mean power profile.
12. An ophthalmic lens element according to claim 2 wherein the difference between r a and r b is not less than substantially 8 mm.
13. An ophthalmic lens element according to claim 2 wherein the first power is in the range from plano to −4.00 D.
14. An ophthalmic element according to claim 1 wherein the foveal vision zone includes an aperture having a shape and/or size that corresponds with the extent of a wearer's typical eye rotations before they engage head rotation.
15. A series of ophthalmic lens elements according to claim 1 wherein each lens in the series provides a peripheral region having a range of positive mean power corresponding with different peripheral correction requirements.
16. A series of ophthalmic lens elements according to claim 15 wherein for each lens in the series the size and/or shape of the central region is associated with a predetermined range of eye rotations for the wearer.
17. An ophthalmic lens element including a lens surface having:
a horizontal meridian and a vertical meridian;
a central region including a foveal vision zone providing a surface power to achieve a refracting power for providing clear foveal vision for a wearer; and
a peripheral region of positive surface mean power relative to the surface power of the central region, the peripheral region including dual progressive zones located bilaterally of the vertical meridian and extending radially outwardly along the horizontal meridian from the central region, each progressive zone providing a gradual increase in surface mean power from the surface power of the central region;
wherein the lens surface provides a distribution of surface astigmatism which provides, along the horizontal meridian, a relatively low surface astigmatism in the central region and the progressive zones.
18. An ophthalmic lens element according to claim 17 wherein each progressive zone provides a mean surface power profile along a respective horizontal semi-meridian that provides a positive surface power gradient over a range defined by r a ≦r x ≦r b in which r a and r b are radial distances along each horizontal semi-meridian from the optical centre of the lens.
19. An ophthalmic lens element according to claim 17 wherein the refracting power is a prescribed power for providing an optical correction corresponding to a wearer's on-axis distance vision viewing requirements.
20. An ophthalmic lens element according to claim 17 wherein the positive surface power in the progressive zones provides an optical correction for retarding or arresting myopia associated with a peripheral region of the retina along the horizontal meridian of the wearer's eye.
21. An ophthalmic lens element according to claim 18 wherein the range defined by r a ≦r x ≦r b is substantially 10 mm≦r x ≦22 mm.
22. An ophthalmic lens element according to claim 18 wherein the positive gradient over the range r a ≦r x ≦r b provides a positive mean surface power increase of at least 1.00 D relative to the surface power at the optical centre.
23. An ophthalmic lens element according to claim 18 wherein the positive gradient over the range r a ≦r x ≦r b provides a positive mean surface power increase of at least 1.50 D relative to the surface power at the optical centre.
24. An ophthalmic lens element according to claim 18 wherein the positive gradient over the range r a ≦ r x≦r b provides a positive mean power increase of at least 2.00 D relative to the surface power at the optical centre.
25. An ophthalmic lens element according to claim 18 wherein the positive gradient over the range r a ≦r x ≦r b provides a positive mean power increase of at least 2.50 D relative to the surface power at the optical centre.
26. An ophthalmic lens element according to claim 18 wherein the positive gradient over the range r a ≦r x ≦r b provides a positive mean power increase of at least 3.00 D relative to the refracting power at the optical centre.
27. An ophthalmic lens element according to claim 18 wherein r a corresponds with a boundary between the foveal vision zone and the progressive zones defined by a +0.25 D contour of mean surface power on the mean power profile.
28. An ophthalmic lens element according to claim 18 wherein the difference between r a and r b is not less than substantially 8 mm.
29. An ophthalmic lens element according to claim 17 wherein the foveal vision zone includes an aperture having a shape and/or size that corresponds with the extent of a wearer's typical eye rotations before they engage head rotation.
30. A series of ophthalmic lens elements according to claim 17 wherein each lens in the series provides a peripheral region having a range of positive mean power corresponding with different peripheral correction requirements.
31. A series of ophthalmic lens elements according to claim 30 wherein for each lens in the series the size and/or shape of the central region is associated with a predetermined range of eye rotations for the wearer.
32. A method of dispensing or designing an ophthalmic lens element for retarding or arresting myopia in a wearer's eye, the method including:
obtaining, for the wearer:
a first required value of optical correction for foveal vision for on-axis viewing tasks; and
a second required value of optical correction for providing a stimulus for retarding or arresting myopia in a peripheral region of the wearer's eye located along the horizontal meridian of the eye;
selecting or designing an ophthalmic lens element according to the values of optical correction, the ophthalmic lens element having a front surface and a rear surface, at least one of the surfaces including a horizontal meridian and a vertical meridian, the lens element including:
a central region including a foveal vision zone providing a first power corresponding to the first required value; and
a peripheral region of positive power relative to the first power, the peripheral region including dual progressive zones located bilaterally of the vertical meridian and extending radially outwardly from the central region, the progressive zones providing a value or distribution of plus power according to the second required value;
wherein the lens element provides a distribution of surface astigmatism which provides, on the horizontal meridian, a relatively low surface astigmatism in the central region and the progressive zones.
33. A semi-finished ophthalmic lens blank including a first surface having:
a horizontal meridian and a vertical meridian;
a central region including a foveal vision zone providing a surface power to achieve a refracting power for providing clear foveal vision for a wearer; and
a first progressive zone located nasally of the central region and a second progressive zone located temporally of the central region, each progressive zone extending radially outwardly from the central region to provide a gradual increase in surface mean power along the horizontal meridian;
wherein the surface provides a distribution of surface astigmatism which provides, along the horizontal meridian, a relatively low surface astigmatism in the central region and the progressive zones.
34. A finished lens element for a wearer, the finished lens element formed from the semi-finished ophthalmic lens of claim 33 , the finished lens element providing a second surface which optically combines with the first surface so that when worn by the wearer the finished lens element positions the tangential focal plane and the sagittal focal plane on or in front of the wearer's retina along the horizontal meridian of the eye.
35. A finished lens element according to claim 34 wherein the tangential focal plane leads the sagittal focal plane.
36. A finished lens element according to claim 34 wherein the sagittal focal plane leads the tangential focal plane.