Method of modifying an dioptric function of an ophthalmic lens surface
A method implemented by computer means of modifying an initial dioptric function of an initial ophthalmic lens surface, for manufacturing an ophthalmic lens, the method comprising: an initial surface providing step (S 1 ), during which an initial surface Sini associated with a first coordinate system is provided, said initial surface Sini comprising a plurality of surface points P 1 , each surface point P 1 having a mean sphere Sph(P 1 ) and a cylinder Cyl(P 1 ), said initial surface Sini providing said initial dioptric function, a modifying surface selection step (S 2 ), during which a number n of nonzero modifying surfaces Smod 1 , . . . , Smod n is selected, said modifying surfaces Smod 1 , . . . , Smod n being associated with a second coordinate system, the modifying surface Smod i comprising a plurality of surface points P i1 , . . . P ij , . . . , P imi , each surface point P ij having a mean sphere Sph(P ij ) and a cylinder Cyl(P ij ), n, i, j, m i being integers with n≥1, 1≤i≤n, 1≤j≤m i and m i ≥1, an orientation step (S 3 ), during which the relative position and orientation of the first coordinate system and the second coordinate system is determined, a combining step (S 4 ), during which the initial surface Sini and the n modifying surfaces are combined to obtain a functionalized ophthalmic lens surface according to the expression: S func= Sini+Σ i=1 i=n alpha i ·Smod i wherein the normalized sphere standard deviation of the normalized sphere values Sph′ Smodi of a normalized modifying surface SNmod i is smaller than or equal to 0.2, with: the normalized modifying surface SNmod i corresponding to the modifying surface Smod i to which the best sphero-toric surface has been subtracted, and the normalized sphere values over the normalized modifying surface SNmod i at a point P ij of Smod i having the coordinate (x,y,z) being: Sph S modi ′ ( x , y ) = ⌊ SphN S mod i ( x , y ) - min ( SphN S mod i ) ⌋ [ max ( SphN S mod i ) - min ( SphN S mod i ) ] SphN Smod,i (x,y) being the sphere over the normalized modifying surface SNmod i , at the point of SNmod i having the coordinate (x,y), max(SphN Smod,i ) being the greatest value of sphere over the normalized modifying surface SNmod i , min(SphN Smod,i ) being the smallest value of sphere over the normalized modifying surface SN modi , alpha i being a nonzero weighting coefficient.
1. A method implemented by a computer of modifying an initial dioptric function of an initial ophthalmic lens surface, for manufacturing an ophthalmic lens, the method comprising:
obtaining information of an initial surface Sini associated with a first coordinate system, said initial surface Sini comprising a plurality of surface points P 1 , each surface point P 1 having a mean sphere Sph(P 1 ) and a cylinder Cyl(P 1 ), said initial surface Sini providing said initial dioptric function;
selecting a number n of nonzero modifying surfaces Smod 1 , . . . , Smod n , said modifying surfaces Smod 1 , . . . , Smod n being associated with a second coordinate system, the modifying surface Smod i comprising a plurality of surface points P i1 , . . . P ij , . . . , P imi , each surface point P ij having a mean sphere Sph(P ij ) and a cylinder Cyl(P ij ), n, i, j, m i being integers with n≥1, 1≤i≤n, 1≤j≤m i and m i ≥1;
determining a relative position and orientation of the first coordinate system and the second coordinate system, the determining of the position and the orientation being achieved by positioning and orienting the first coordinate system and the second coordinate system in a third common coordinate system; and
combining the initial surface Sini and the n modifying surfaces, in association with the third coordinate system, to obtain a functionalized ophthalmic lens surface according to the expression:
S func= Sini+Σ i=1 i=n alpha i ·Smod i
wherein a normalized sphere standard deviation of normalized sphere values Sph′ smodi of a normalized modifying surface SNmod i is smaller than or equal to 0.2, with:
the normalized modifying surface SNmod i corresponding to the modifying surface Smod i to which a best sphero-toric surface has been subtracted, and
the normalized sphere values over the normalized modifying surface SNmod i at a point P ij of Smod i having the coordinate (x,y,z) being:
Sph
S
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x
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=
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SphN Smod,i (x,y) being the sphere over the normalized modifying surface SNmod i , at the point of SNmod i having the coordinate (x,y),
max(SphN Smod,i ) being the greatest value of sphere over the normalized modifying surface SNmod i ,
min(SphN Smod,i ) being the smallest value of sphere over the normalized modifying surface SN modi , and
alpha i being a nonzero weighting coefficient.
2. The method according to claim 1 , wherein the standard deviation of the normalized sphere values Sph′ i along a central line of the normalized modifying surface is smaller than or equal to 0.3.
3. The method according to claim 1 , wherein an area of the normalized modifying surface SNmod i having normalized sphere values Sph′ i smaller than 0.2 represents less than 25% of a total surface area of the normalized modifying surface SNmod i .
4. The method according to claim 1 , wherein an area of the normalized modifying surface SNmod i having a normalized cylinder values Cyl′ Smodi greater than 0.6 represent less than 25% of a total surface area of the normalized modifying surface SNmod i , with the normalized cylinder values over the normalized modifying surface at a point P ij of Smod i having the coordinate (x,y,z) being:
Cyl
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CylN Smod,i (x,y,z) being the cylinder over the normalized modifying surface SNmod i at the point SNmod i having the coordinate (x,y),
max(CylN Smod,i ) being the greatest value of sphere over the normalized modifying surface SNmod i , and
min(CylN Smodi ) being the smallest value of sphere over the normalized modifying surface SNmod i .
5. The method according to claim 4 , wherein an average value of the normalized cylinder Cyl′ Smodi over the normalized modifying surface SNmod i is smaller than or equal to 0.35.
6. The method according to claim 1 , wherein said first coordinate system comprising an origin, wherein the normalized modifying surface SNmod i is calculated considering a disk of 60 mm diameter centered on the origin of the first coordinate system.
7. The method according to claim 6 , wherein the origin of the first coordinate system is located on the optical center of the lens when the ophthalmic lens is a single vision lens, or is located in the middle of the micro-engravings when the ophthalmic lens is a multifocal lens.
8. The method according to claim 1 , wherein during the combining, a sphero-toric surface (ST) is further added to the initial surface Sini to obtain the functionalized ophthalmic lens surface.
9. The method according to claim 1 , further comprising determining the value of the weighting coefficient alpha i based on a wearer parameter of the ophthalmic lens.
10. The method according to claim 1 , wherein said ophthalmic lens comprises a far vision control point (FVP) and a near vision control point (NVP), wherein Sigma=Σ i=1 i=n alpha i ·Smod i forms a surface gathering a plurality of surface points P 2 1 , . . . , P 2 q , each surface point P 2 j having a mean sphere Sph(P 2 j ) and a cylinder Cyl(P 2 j ), with q, j being integers, and 1≤j≤q, wherein for any surface points (P 3 ) of the surface Sigma located in a vicinity of the far vision control point (FVP), the mean sphere and the cylinder are such that Sph(P 3 )<0.12 and Cyl(P 3 )<0.12.
11. The method according to claim 10 , wherein for any surface points (P 4 ) of the surface Sigma located in a vicinity of the far near control point (NVP), the mean sphere and the cylinder are such that Sph(P 3 )<0.12 and Cyl(P 3 )<0.12.
12. A method of manufacturing an ophthalmic lens comprising:
determining the surfaces of the ophthalmic lens and relative positions of the front and rear surfaces of the ophthalmic lens; and
manufacturing the ophthalmic lens,
wherein during the determining, the dioptric function of at least one of the ophthalmic lens surfaces is modified according to the method of claim 1 .
13. An ophthalmic lens calculating device comprising:
processing circuitry configured to
receive an ophthalmic lens order request comprising at least a wearer's ophthalmic prescription and at least one additional function to add to said ophthalmic lens,
determine an initial surface Sini, associated with a first coordinate system, and relative positions of an ophthalmic lens based on the order request,
determine at least one modifying surface Smod i , associated with a second coordinate system, and at least one nonzero weighting coefficient alpha i corresponding to the at least one desired additional function to add to said ophthalmic lens, and
combine the initial surface Sini and the at least one modifying surface Smod i , in a third coordinate system,
wherein position and orientation of the first coordinate system and the second coordinate system are determined by positioning and orienting the first coordinate system and the second coordinate system in a third common coordinate system.
14. The ophthalmic lens determining device according to claim 13 , wherein the processing circuitry is configured to communicate with at least one distant entity to provide the modifying surface Smod i and/or the corresponding weighting coefficient alpha i .