Lens element with improved visual performance

1 . A lens element to be worn by a wearer and to provide a refractive power based on a prescription of the wearer for correcting an abnormal refraction of the eye of the wearer, the lens element comprising:

an optical microstructure having an optical function of not focusing an image on a retina of the eye of the wearer to slow down progression of the abnormal refraction of the eye of the wearer,

wherein a modulation transfer function of the lens element is greater or equal to 0.07 over a range of spatial frequencies comprised from 10 to 25 cycles per degree, when measured through the optical microstructure for a pupil aperture of 4 mm centered at 6.6 mm from the optical center of the lens element, for a gaze direction of 15° downwards, and a light beam arriving normal to the surface of the lens element.

2 . The lens element according to claim 1 , wherein the modulation transfer function of the lens element is greater or equal to 0.10.

3 . The lens element according to claim 1 , further comprising a refractive area configured to provide the refractive power based on the prescription of the wearer for correcting the abnormal refraction of the eye of the wearer.

4 . The lens element according to claim 1 , wherein the optical microstructure has an additional optical function of providing the refractive power based on the prescription of the wearer for correcting the abnormal refraction of the eye of the wearer.

5 . The lens element according to claim 1 , wherein the modulation transfer function is greater or equal to 0.15 over the range of spatial frequencies comprised from 10 to 15 cycles per degree, when measured through the optical microstructure for a pupil aperture of 4 mm centered at 6.6 mm from the optical center of the lens element.

6 . The lens element according to claim 5 , wherein the modulation transfer function is greater or equal to 0.25.

7 . The lens element according to claim 1 , wherein the modulation transfer function, for foveal vision, is greater or equal to 0.07 over the range of spatial frequencies comprised from 20 to 25 cycles per degree, when measured through the optical microstructure for a pupil aperture of 4 mm centered at 6.6 mm from the optical center of the lens element.

8 . The lens element according to claim 7 , wherein the modulation transfer function, for foveal vision, is greater or equal to 0.10.

9 . The lens element according to claim 1 , wherein the modulation transfer function, for foveal vision, is greater or equal to 0.85 over the range of spatial frequencies comprised from 0.5 to 3 cycles per degree, when measured through the optical microstructure for a pupil aperture of 4 mm centered at 6.6 mm from the optical center of the lens element.

10 . The lens element according to claim 9 , wherein the modulation transfer function, for foveal vision, is greater or equal to 0.85.

11 . The lens element according to claim 1 , wherein the modulation transfer function, for foveal vision, is a horizontal modulation transfer function or a vertical modulation transfer function.

12 . The lens element according to claim 1 , wherein the optical microstructure is disposed on an object-side surface and/or an eye-side surface and/or between the object-side surface and the eye-side surface of the lens element.

13 . The lens element according to claim 12 , further comprising a coating on the object-side surface and/or the eye-side surface.

14 . The lens element according to claim 1 , wherein the optical microstructure comprises a plurality of optical elements, including micro-lenses.

15 . The lens element according to claim 14 , wherein the plurality of optical elements is positioned in a network, including a grid, a honeycomb, or concentric rings.

16 . The lens element according to claim 1 ,

wherein the modulation transfer function of the lens element, for foveal vision, is measured through a surface of the lens element, and

wherein the optical microstructure covers greater than or equal to 20% of the surface.

17 . The lens element according to claim 16 , wherein the optical microstructure covers greater than or equal to 40% of the surface.

18 . The lens element according to claim 1 , wherein the modulation transfer function of the lens element, for peripheral vision, is less than or equal to 0.8 over the range of spatial frequencies comprised from 3 to 7 cycles per degree, when measured for a pupil aperture of 4 mm centered at 6.6 mm from the optical center of the lens element.

19 . The lens element according to claim 1 , wherein the modulation transfer function, for peripheral vision, is greater or equal to 0.15 over the range of spatial frequencies comprised from 10 to 20 cycles per degree, when measured for a pupil aperture of 4 mm centered at 6.6 mm from the optical center of the lens element.

20 . A computer-implemented method for determining a lens element to be worn by a wearer, to provide a refractive power based on a prescription of the wearer for correcting an abnormal refraction of the eye of the wearer and to slow down progression of an abnormal refraction of said eye of the wearer,

the lens element comprising an optical microstructure having an optical function of not focusing an image on a retina of the eye of the wearer to slow down the progression of the abnormal refraction of the eye of the wearer; and

the method comprising the following steps:

providing a prescription of the wearer, and

determining the optical microstructure so that the modulation transfer function is greater or equal to 0.07 over a range of spatial frequencies comprised from 10 to 25 cycles per degree, when measured through the optical microstructure for a pupil aperture of 4 mm centered at 6.6 mm from the optical center of the lens element, for a gaze direction of 15° downwards, and a light beam arriving normal to the surface of the lens element.