Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
  • G02C7/00—Optical parts
  • G02C7/02—Lenses; Lens systems ; Methods of designing lenses

Definitions

• the optically useful area covers the entire lens which has a diameter of limited value.
• a peripheral zone may be provided on the periphery of the ophthalmic lens. This zone is said to be peripheral because it does not meet the prescribed optical correction conditions and has significant obliquity defects. The optical defects of the peripheral zone do not affect the visual comfort of the wearer because this area is outside the field of view of the wearer.
• an ophthalmic lens may have such a peripheral area.
• the lens has a large diameter which can be imposed by the shape of the frame, for example an elongated frame with a strong curve, or when the power prescription is high, the lens then having a thick edge or large center that is sought to reduce.
• a peripheral zone intended to improve the peripheral vision of the wearer. For example, distortion, chromatic aberrations, prismatic deviations or other optical parameters can be optimized in the peripheral area to the detriment of the prescribed optical correction.
• the glass has a spherical or toric surface of strong camber (or base), between 6 diopters and 10 diopters, and a calculated face specifically to achieve the optimal ametropia correction of the wearer at the optical center and in the field of view.
• strong camber of the front face causes a large thickness of the glass on the edges in the case of a negative lens or a large thickness of the glass in the center in the case of a positive lens. These high thicknesses increase the weight of the lenses, which affects the comfort of the wearer and make them unsightly.
• the edge thickness must be limited to allow mounting of the glass in the frame.
• US-A-6 199 983 proposes to customize a progressive lens according to the "lifestyle" of the wearer, for example taking into account Ia. shape of the mount.
• Nikon® sells under the brand name Seemax® a unifocal lens optimized according to the size and shape of the frame.
• the invention accordingly proposes a method for determining a personalized ophthalmic lens for a given wearer, the method comprising the steps of:
• FIG. 13 a graph of optical power carrying along the meridian of a lens according to a second embodiment of the invention optimized in thickness for an eyewash;
• FIGS. 14 and 15 optical power and astigmatism cards resulting for the lens of FIG. 13;
• Figures 16 and 17 are diagrammatic sectional views respectively for the lens of Figure 13 and for a non-optimized lens of the same prescription;
• the invention proposes a method for determining an ophthalmic lens having a central zone optimized in sharpness according to the wearer's prescription and an optimized peripheral zone so as to improve a given parameter of the lens, for example its thickness or a vision characteristic.
• peripheral such as distortion, prismatic effects, chromatic aberrations or others.
• the size of the central zone is determined according to the wearer's vision strategy and in particular according to his eye-head behavior.
• the invention proposes to adapt the size of the optically useful central area according to the wearer's eye-head behavior so that the optimization of the peripheral zone is maximal for a headwalker and is not perceived as a hindrance. for an eyewash.
• the eye-head behavior of the wearer can be measured for example with a VisionPrint System TM type device developed by the applicant.
• Eye-head coordination parameters are determined. These parameters may be those measured to define the lenses marketed under the trademark VARILUX IPSEO, namely a gain GA and a coefficient of stability ST.
• the gain GA is a parameter that gives the proportion of the movement of the head in the total movement of the gaze to reach a target.
• the gain GA can be defined as the ratio of the angle of the head to the angle of gaze for a fixed point in a given gaze direction.
• the gain has a value between 0.00 and 1.00.
• a gain value of 0.31 reflects behavior with predominant eye movement.
• the stability coefficient ST is a parameter that reflects the stability of the behavior, ie the standard deviation around the value of the gain. Most carriers are stable and the ST value is generally less than 0.15.
• the connection between the central and peripheral zones is done directly on the same surface when calculating optimization of the prescription surface of the lens.
• the peripheral zone is optimized to reduce the thickness, it is necessary to connect the central and peripheral zones by surface interpolation.
• the lens has a first face that can be spherical, or toric and a second complex face calculated to adapt the lens to the ametropia of the wearer and to optimize the thickness of the lens in the conditions of the worn.
• the three zones 15, 16 and 17 of the rear face are centered on the same point, preferably on the mounting cross which corresponds to the primary direction of gaze of the wearer in the conditions of the worn.
• the three zones 15, 16 and 17 of the rear face of the lens are of identical shape, this shape (circular, elliptical, or other) being chosen according to the frame and / or the prescription.
• the size of the central zone 15 is imposed by the eye-head behavior of the wearer and the connection zone 16 must have a width that is sufficiently large to limit the visibility of the transition and is sufficiently small for the peripheral zone 17 to allow a significant optimization of the thickness.
• the rear face and / or the front face of the lens can be varied.
• the face or faces that vary can be represented by Zernike polynomials; it is possible to use an aspherical sheet superimposed on one or other of the faces, and to vary this aspherical sheet.
• Optimization can use the techniques known per se. In particular, the depreciated least squares optimization (DLS) method can be used.
• DLS depreciated least squares optimization

Landscapes

• Health & Medical Sciences (AREA)
• Ophthalmology & Optometry (AREA)
• Physics & Mathematics (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Eyeglasses (AREA)
• Eye Examination Apparatus (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=38236194

Family Applications (1)

Country Status (5)

Families Citing this family (16)

Family Cites Families (21)

• 2006
  • 2006-12-22 FR FR0611252A patent/FR2910645B1/fr not_active Expired - Fee Related
• 2007
  • 2007-11-20 EP EP07870303A patent/EP2104878A1/de not_active Withdrawn
  • 2007-11-20 JP JP2009542122A patent/JP5542447B2/ja not_active Expired - Fee Related
  • 2007-11-20 US US12/520,865 patent/US20100149492A1/en not_active Abandoned
  • 2007-11-20 WO PCT/FR2007/001897 patent/WO2008081086A1/fr active Application Filing

Non-Patent Citations (2)

Also Published As

Similar Documents

Legal Events