Progressive multifocal ophthalmic lens designed to inhibit progressive myopia of the wearer

Patent metadata

Field	Value
Publication number	US-9791718-B2
Application number	US-201314418715-A
Country	US
Kind code	B2
Filing date	Jul 29, 2013
Priority date	Jul 31, 2012
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

Progressive multifocal ophthalmic lens having a power addition (Add) and an astigmatism prescription, and having a far vision point CM, a near vision point NV, and an intermediate vision point IV positioned between CM and NV. The resulting astigmatism in the far and near vision zones is smaller than or equal to the resulting astigmatism in the intermediate vision zone, wherein the resulting astigmatism is the difference between the prescribed astigmatism and the astigmatism generated by the working lens under usual wear conditions. The lens provides good optical quality images in the far and near vision zones, and the resulting astigmatism in the intermediate vision zone encourages the wearer to use the far and near vision zones rather than the intermediate vision zone, thus reducing the risk of increasing the degree of myopia of the wearer in the long term.

First claim

The invention claimed is:

1. A lens provided as a progressive multifocal ophthalmic lens for positioning in front of an eye under usual wear conditions having a power addition prescription and an astigmatism prescription and comprising:
a far vision point;
a near vision point;
an intermediate vision point;
such that the lens has, under the usual wear conditions, at least:
a far-vision zone around the far vision point, the far-vision zone corresponding to an intersection of the lens and a far vision cone, the far vision cone being a right circular cone with an axis of the far vision cone passing through a center of rotation of the eye and the far vision point, an aperture of the far vision cone being greater than or equal to

PL
9

 and smaller than or equal to

PL
3

,

 with PL as an angular progression length of the lens,
a near-vision zone around the near vision point, the near-vision zone corresponding to an intersection of the lens and a near vision cone, the near vision cone being a right circular cone with an axis of the near vision cone passing through the center of rotation of the eye and the near vision point, an aperture of the near vision cone being greater than or equal to

PL
9

 and smaller than or equal to

PL
3

,

 and
an intermediate-vision zone around the intermediate vision point, the intermediate-vision zone corresponding to an intersection of the lens and an intermediate vision cone, the intermediate vision cone being a right circular cone with an axis of the intermediate vision cone passing through the center of rotation of the eye and the intermediate vision point, an aperture of the intermediate vision cone being greater than or equal to

PL
9

and smaller than or equal to

PL
3

,

and the intermediate vision point is positioned between the far vision point and the near vision point, so that:
⅓|α F −α N |≦|α F −α 1 |≦⅔|α F −α N |; and

min(β N ,β F )≦β 1 ≦max(β N ,β F ),

with α F , β F , α N , β N , α I and β I as angular coordinates of respectively the far vision point, the near vision point and the intermediate vision point in a Fick system,
in which a resulting astigmatism in one or more of the far-vision and near-vision zones is smaller than or equal to

Add
3

,

with Add as a value of the power addition prescription, and
a resulting astigmatism in the intermediate-vision zone is greater than or equal to 0.4×Add and smaller than or equal to 2×Add,
wherein the angular progression length is an angle of lowered viewing from a fitting cross to a point of a meridian line at which optical power reaches 100% of the addition prescription under the usual wearing conditions, and
wherein the angular progression length is greater than or equal to 20° and smaller than or equal to 32°.

2. The lens according to claim 1 , further comprising a peripheral zone of positive power relative to power in the far-vision zone, the peripheral zone including progressive zones extending radially outwardly from the far vision point.

3. The lens according to claim 1 , wherein the intermediate vision point is positioned between the far vision and near vision points so that:
0.4×|α F −α N |≦|α F −α I |.

4. The lens according to claim 1 , wherein the intermediate vision point is positioned between the far vision and near vision points so that:
α F −α I 0.5×|α F −α N |.

5. The lens according to claim 1 , wherein the power addition prescription is greater than or equal to 1.5 diopters and smaller than or equal to 2.5 diopters.

6. The lens according to claim 1 , wherein the resulting astigmatism in the far-vision and near-vision zones is smaller than or equal to 0.25 diopters.

7. The lens according to claim 1 , wherein a surface of the intermediate-vision zone is smaller than surfaces of the far-vision and near-vision zones.

8. The lens according to claim 1 , wherein data about the lens is obtained by a visual apparatus.

9. The lens according to claim 1 , wherein the lens is used to slow down development of progressive myopia in the eye of a wearer provided the lens.

10. The lens according to claim 1 , wherein a resulting astigmatism is a difference between the prescribed astigmatism and an astigmatism generated by a final lens in a reference frame associated with the eye and for each direction of glance.

11. A method of providing a lens as a progressive multifocal ophthalmic lens for positioning in front of an eye under usual wear conditions having a power addition prescription and an astigmatism prescription, the method comprising:
providing a far vision point on the lens, such that a far-vision zone is around the far vision point, the far-vision zone corresponding to an intersection of the lens and a far vision cone, the far vision cone being a right circular cone with an axis of the far vision cone passing through a center of rotation of the eye and the far vision point, an aperture of the far vision cone being greater than or equal to

PL
9

and smaller than or equal to

PL
3

,

with PL as an angular progression length of the lens;
providing a near vision point on the lens, such that a near-vision zone is around the near vision point, the near-vision zone corresponding to an intersection of the lens and a near vision cone, the near vision cone being a right circular cone with an axis of the near vision cone passing through the center of rotation of the eye and the near vision point, an aperture of the near vision cone being greater than or equal to

PL
9

 and smaller than or equal to

PL
3

;

 and
providing an intermediate vision point on the lens, such that an intermediate-vision zone is around the intermediate vision point, the intermediate-vision zone corresponding to an intersection of the lens and an intermediate vision cone, the intermediate vision cone being a right circular cone with an axis of the intermediate vision cone passing through the center of rotation of the eye and t

Assignees

• Essilor Int (Compagnie Générale D'Optique
• Essilor Int

Inventors

• Drobe Björn
• Carimalo Céline

Classifications

• G02C2202/24

  Myopia progression prevention · CPC title

• G02C7/066 Primary

  Shape, location or size of the viewing zones · CPC title

• G02C7/065 Primary

  Properties on the principal line · CPC title

• G02C7/027

  considering wearer's parameters · CPC title

• G02C7/028

  Special mathematical design techniques · CPC title