METHOD FOR DETERMINING A SET OF PROGRESSIVE MULTIFOCAL OPHTHALMIC LENSES

• US 20090290121A1
• Filed: 12/12/2006
• Published: 11/26/2009
• Est. Priority Date: 12/13/2005
• Status: Active Grant

• Current Assignee: Essilor International SA (EssilorLuxottica SA)
• Original Assignee: Essilor International SA (EssilorLuxottica SA)
• Inventors: Drobe, Bjorn, Pedrono, Claude
• Granted Patent: US 7,997,726 B2
• Time in Patent Office: Days
• US Class Current: 351/169
• CPC Class Codes: G02C 7/025 considering parameters of the viewed object
• CPC Class Codes: G02C 7/066 Shape, location or size of the viewing zones

Abstract

A method for determining by optimization a set of progressive ophthalmic lenses for a given user for whom a near vision power addition (Add_n) has been prescribed includes the following steps: measuring the user'"'"'s near vision individual physiological parameters; determining an ergorama associating, on each lens, a target point in each look direction in worn conditions; determining a target power defect and a resulting target astigmatism for each direction of look under worn conditions, the target power defect and the resulting target astigmatism being determined from the user'"'"'s measured physiological parameters; computing the power required for each lens for said ergorama by successive iterations to reach the target power defect and the target astigmatism for each look direction.

Claims

1. Method for determining by optimization a set of progressive ophthalmic lenses for a given wearer to whom a near-vision power addition (Add_n) has been prescribed, comprising the steps of:

measuring individual physiological parameters of the wearer in near-vision;

determining an ergorama associating, on each lens, a point aimed at for each direction of view under wearing conditions.

determining a power defect target and a resulting astigmatism target for each direction of view under wearing conditions, the target power defect and the target resulting astigmatism being determined from the measured physiological parameters of the wearer;

calculating the power required on each lens for said ergorama by successive iterations to achieve the target power defect and the target astigmatism defect for each direction of view.

2. The method of claim 1 in which the power defect target is determined by the following relationship:

$\mathrm{DefP}=\frac{\left({\mathrm{ProbH}}^{\mathrm{\prime <br><br>}}\right)·<br><br>\left(\left(\frac{{\mathrm{Add}}_n}{a}\right)-{\mathrm{Add}}_r\right)}{\mathrm{kp}}$

With,

ProbH′

, the probability of occurrence of the orientation of view;

Add_n the nominal prescribed addition for the wearer;

Add_r the addition required at a point of the lens;

and kp and a, constants determined as a function of the prescribed addition and the physiological parameters of the wearer.

3. The method of claim 1 in which the resulting astigmatism target is determined by the following relationship:

A=Ast_MAX·

(ProbH′

)

With,

ProbH′

, the probability of occurrence of the orientation of view; and

;

${\mathrm{Ast}}_{\mathrm{MAX}}={\mathrm{Add}}_n\times <br><br>\left(k+b\right)\times <br><br>\left(0.25+{\mathrm{<br><br>}}^{\frac{{\left(\ln <br><br>\left(\frac{{\mathrm{elev}}_{\mathrm{reg}}-121}{-\mathrm{alpha}<br><br><br><br>0}\right)\right)}^2}{\mathrm{sigma}}}\right)$

Where Add_n is the nominal prescribed addition for the wearer; and

k, b, alpha0 and sigma, constants determined as a function of the physiological parameters of the wearer.

4. The method of claim 1, in which the measured physiological parameters of the wearer are at least the vertical and horizontal coefficients of participation of the head in near-vision, the vertical horopter in near-vision and the preferred near-vision distance Dnv.

5. A set of progressive multifocal ophthalmic lenses personalized to the needs of a given wearer to whom a power addition has been prescribed each lens being determined by means of an ergorama associating a point aimed at for each direction of view tinder wearing conditions, each lens having under wearing conditions, an optical power and a resulting astigmatism controlled for a point aimed at in the ergorama by physiological parameters of the wearer.

6. The set of lenses of claim 5, in which the optical power, on each lens tinder wearing conditions for a point aimed at in the ergorama, is determined by the following relationship:

$\mathrm{DefP}=\frac{\left({\mathrm{ProbH}}^{\mathrm{\prime <br><br>}}\right)·<br><br>\left(\left(\frac{{\mathrm{Add}}_n}{a}\right)-{\mathrm{Add}}_r\right)}{\mathrm{kp}}$

With,

ProbH′

, the probability of occurrence of the orientation of view;

Add_n the nominal prescribed addition for the wearer;

Add_r the addition required at a point of the lens; and

kp and a, constants determined in relation to the prescribed addition and the physiological parameters of the wearer.

7. The set of lenses of claim 5, in which the resulting astigmatism, on each lens under wearing conditions for a point aimed at in the ergorama, is determined by the following relationship:

A=Ast_MAX·

(ProbH′

)

With,

ProbH′

, the probability of occurrence of the orientation of view;

And;

${\mathrm{Ast}}_{\mathrm{MAX}}={\mathrm{Add}}_n\times <br><br>\left(k+b\right)\times <br><br>\left(0.25+{\mathrm{<br><br>}}^{\frac{{\left(\ln <br><br>\left(\frac{{\mathrm{elev}}_{\mathrm{reg}}-121}{-\mathrm{alpha}<br><br><br><br>0}\right)\right)}^2}{\mathrm{sigma}}}\right)$

Where Add_n is the nominal prescribed addition for the wearer; and

k, b, alpha0 and sigma, constants determined in relation to the physiological parameters of the wearer.

8. A visual device comprising a set of progressive multifocal ophthalmic lenses personalized to the needs of a given wearer to

whom at power addition has been prescribed, each lens being determined by means of an ergorama associating a point aimed at for each direction of view under wearing conditions, each lens having under wearing conditions, an optical power and a resulting astigmatism controlled for a point aimed at in the ergorama by physiological parameters of the wearer.

10. The visual device of claim 8, in which the optical power, on each lens under wearing conditions for a point aimed at in the ergorama, is determined by the following relationship:

$\mathrm{DefP}=\frac{\left({\mathrm{ProbH}}^{\mathrm{\prime <br><br>}}\right)<br><br>\left(\left(\frac{{\mathrm{Add}}_n}{a}\right)-{\mathrm{Add}}_r\right)}{\mathrm{kp}}$

With,

ProbH′

, the probability of occurrence of the orientation of view;

Add_n the nominal prescribed addition for the wearer;

Add_r the addition required at a point of the lens; and

kp and a, constants determined in relation to the prescribed addition and the physiological parameters of the wearer.

11. The visual device of claim 8, in which the resulting astigmatism, on each lens under wearing conditions for a point aimed at in the ergorama, is determined by the following relationship:

A=Ast_MAX(ProbH′

)

With,

ProbH′

, the probability of occurrence of the orientation of view;

And;

${\mathrm{Ast}}_{\mathrm{MAX}}={\mathrm{Add}}_n\times <br><br>\left(k+b\right)\times <br><br>\left(0.25+{\mathrm{<br><br>}}^{\frac{{\left(\ln <br><br>\left(\frac{{\mathrm{elev}}_{\mathrm{reg}}-121}{-\mathrm{alpha}<br><br><br><br>0}\right)\right)}^2}{\mathrm{sigma}}}\right)$

Where Add_n is the nominal prescribed addition for the wearer; and

k, b, alpha0 and sigma, constants determined in relation to the physiological parameters of the wearer.

9. (canceled)