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
  • G02C7/04—Contact lenses for the eyes
  • G02C7/048—Means for stabilising the orientation of lenses in the eye
• • 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
  • G02C7/04—Contact lenses for the eyes
  • G02C7/041—Contact lenses for the eyes bifocal; multifocal
• • 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
  • G02C7/04—Contact lenses for the eyes
  • G02C7/041—Contact lenses for the eyes bifocal; multifocal
  • G02C7/044—Annular configuration, e.g. pupil tuned
• • G—PHYSICS
  • G02—OPTICS
  • G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
  • G02C2202/00—Generic optical aspects applicable to one or more of the subgroups of G02C7/00
  • G02C2202/24—Myopia progression prevention

Definitions

• contact lenses having a toric optical zone are used to correct refractive abnormalities of the eye associated with astigmatism.
• the toric optical zone provides cylindrical correction to compensate for the astigmatism. Since astigmatism requiring vision correction is usually associated with other refractive abnormalities, such as myopia (nearsightedness) or hypermetropia (farsightedness), toric contact lenses are generally prescribed also with a spherical correction to correct myopic astigmatism or hypermetropic astigmatism.
• the toric surface may be formed in either the posterior lens surface (back surface toric lens) or in the anterior lens surface (front surface toric lens).
• toric contact lenses have some type of ballast to inhibit rotation of the lens on the eye so that the cylindrical axis of the toric zone remains generally aligned with the axis of the astigmatism.
• Toric contact lenses are manufactured with a selected relationship (or offset) between the cylindrical axis of the toric optical zone and the orientation of the ballast. This relationship is expressed as the number of degrees (rotational angle) that the cylindrical axis is offset from the orientation axis of the ballast. Accordingly, toric contact lens prescriptions specify this offset, with toric lenses generally being offered in 5 or 10-degree increments ranging from 0° to 180°.
• a prescription for a toric contact lens will typically specify spherical correction (spherical power), cylindrical correction (cylindrical power) and axes offset to define the optical correction, as well as lens diameter and base curve to define fitting parameters.
• ballast is prism ballast, which has proven effective for maintaining a toric contact lens in a desired rotational orientation on the eye.
• prism ballasting is disclosed in US 6, 113,236. Prism may be attained by various manners including:
• this invention provides a contact lens comprising:
• a posterior surface comprising a posterior optical zone surface having a posterior center point, and a posterior peripheral zone;
• an anterior surface comprising an anterior optical zone surface having an anterior center point, and an anterior peripheral zone;
• one of the posterior optical zone and the anterior optical zone surfaces is a toric optical zone surface and the other of the posterior optical zone and the anterior optical zone surfaces is a non-toric optical zone surface;
• non-toric optical zone surface is non-perpendicular to the centerline at its center point, such that the anterior optical zone surface and the posterior optical zone surface are tilted with respect to one another to define a tilt angle therebetween, thereby forming prism in the optical zone;
• posterior and anterior peripheral zones define the peripheral region of the contact lens, and thickness profiles of the peripheral region are independent of said tilt angle.
• the posterior optical zone surface is a toric optical zone surface and the anterior optical zone surface is a non-toric optical zone surface.
• the anterior optical zone surface is a toric optical zone surface and the posterior optical zone surface is a non-toric optical zone surface.
• the tilt angle has a magnitude between 0.1 and 5 degrees, or a magnitude between 0.5 and 2 degrees, or a magnitude of about 1 degree.
• the thickness profiles of the peripheral region are defined radially, for example, at radial increments. There may be at least twelve radial increments, or at least 24 radial increments.
• maximum thicknesses of radial thickness profiles in an inferior section of the peripheral region are greater than radial thickness profiles in a superior section of the peripheral region.
• the non-toric optical zone surface may be spherical or a non-toric asphere, such as an asphere that imparts a predetermined amount of spherical aberration to a refractive correction of the optical zone.
• FIG. 1 is a planar view of a toric contact lens anterior surface.
• FIG. 2 is a cross-section view taken along line A-A of FIG. 1.
• FIG. 3 is a schematic illustration of the tilt angle between the optical zone surfaces.
• FIGS 1 and 2 schematically illustrate a toric contact lens according to various aspects of this invention.
• Toric contact lens 10 includes an optical zone 11 and a peripheral region 13 which terminates at edge 40.
• Toric contact lens 10 includes a posterior surface 20 and an opposed anterior surface 30.
• Posterior surface 20 comprises a posterior optical zone surface 21 having a posterior center point 22, and a posterior peripheral zone 23.
• the posterior optical zone surface 21 is toric.
• Anterior surface 30 comprises an anterior optical zone surface 31 having a posterior center point 32, and a posterior peripheral zone 33.
• the anterior toric optic zone surface 31 is non-toric.
• the posterior and the anterior center points 22, 32 are aligned with one another, such that centerline 12 intersects center points 22, 32.
• the optical zones 21, 31 are not decentered with respect to one another, as in some prior prism ballasted tone contact lenses.
• centerline 12 an imaginary reference line
• anterior optical zone surface 31 is not perpendicular to centerline 12 at its center point 32, such that the anterior optical zone is tilted with respect to the posterior optical zone.
• the tilt between these two surfaces may be defined by tilt angle 14. This tilt between the two optical zone surfaces thereby forms prism in the optical zone of the contact lens. In this illustrated embodiment, the prism is restricted to the optical zone 11.
• FIG. 3 schematically illustrates this tilt angle 14, also designated by ⁇ .
• imaginary line 19 represents the anterior optic zone surface without tilt between the anterior and posterior optical zone surfaces 31, 21, whereby this portion of the optical zone would have a constant thickness x.
• thickness y is greater than thickness x.
• the tilt angle 14 may have a magnitude from 0.1 to 5 degrees, preferably from 0.5 to 2 degrees. In the illustrated embodiment, tilt angle 14 is about 1 degree.
• the thickness profiles of the peripheral region may be defined radially, i.e., along radii generating from the lens center.
• the peripheral thickness profiles could be defined along an infinite number of such radii, but in practice, one designing the toric contact lens will define the peripheral thickness profiles at a selected number of radial increments. This is illustrated in Figure 1, showing the radial 16 spaced by interval 15.
• the peripheral thickness profiles are defined by at least twelve radial increments. As an example, the illustrated embodiment includes 24 radial increments, spaced at 15-degree intervals.
• the thickness profiles of the peripheral region are independent of the tilt between the optical zone surfaces, since these tilted surfaces are restricted to the optical zone 11. Prism is present only in the optical zone, thereby placing less restrictions on design of the peripheral region.
• the maximum thicknesses of the radial thickness profiles in an inferior section 17 of the peripheral region are greater than radial thickness profiles in a superior section 18 of the peripheral region. This is shown in the embodiment illustrated in Figure 2.
• Line A-A in Figure 1 corresponds to what is commonly referred to as the vertical meridian of a contact lens.
• the upper half of the contact lens is commonly referred to as the superior section 18, and the lower half is commonly referred to as the inferior section 17.
• the top of the vertical meridian is referenced as the 90-degree position, and the bottom of the vertical meridian is referenced as 270-degree position.
• the halves of the contact lens lying on the two sides of the vertical meridian are mirror images.
• a representative example of the peripheral region follows, to illustrate one manner of designing the peripheral regions.
• the radial thickness profiles along these radii 16 may have a fairly consistent maximum thickness, which also represents the maximum thickness present in the peripheral region 13.
• the radial thickness profiles may then have maximum thicknesses that taper downwardly from 315 degrees to 0 degrees.
• the radial thickness profiles may then have maximum thicknesses that taper downwardly from 225 degrees to 180 degrees.
• the thickness can taper downwardly along that radii, i.e., taper downwardly from the maximum thickness as the edge 40 of the contact lens is approached.
• peripheral region designs may be selected.
• the main considerations are to provide a peripheral region that provides a contact lens that is relatively easy for a practitioner to fit and that is not uncomfortable while worn.
• the peripheral region in conjunction with the prism in the optical zone, provides a prism ballasted contact lens.
• the prism ballast inhibits rotation of the contact lens while worn.
• the prism ballast returns the contact lens to its intended rotational alignment upon interaction with the eyelids during blinking.
• optical zone 11 provides the desired cylindrical and spherical refractive corrections.
• optical zone surfaces 21, 31, in conjunction with each other provide the refractive corrections, with the toric optical zone surface ensuring the desired cylindrical correction.
• the non-toric optical zone surface may be spherical or may be a non-toric asphere.
• An example of a non-toric asphere is one which imparts a predetermined amount of spherical aberration to the refractive correction of the optical zone, as disclosed in US 5,815,239, for example, the disclosure of which is incorporated by reference herein.
• the non-toric optic zone surface further may comprise a multifocal surface, such as where the non-toric optic zone surface includes a central optic zone providing a near vision correction and an outer optic zone providing a far vision correction.
• the non-toric optic zone surface may further include an intermediate optic zone, between a central optic zone and an outer optic zone, providing an intermediate vision correction.
• Multifocal optic zone surface designs which may be employed in the present invention include those disclosed in US 5,754,270, for example, the disclosure of which is incorporated by reference herein.
• the posterior optical zone surface 21 was sometimes described as toric with the anterior optical surface 31 being described as non-toric.
• this invention is applicable for back surface toric contact lenses and front surface toric contact lenses. Accordingly, this invention includes the posterior optical zone surface 21 being non-toric with the anterior optical surface 31 being toric.

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• Health & Medical Sciences (AREA)
• Ophthalmology & Optometry (AREA)
• Physics & Mathematics (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Eyeglasses (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)
• Eye Examination Apparatus (AREA)
• Prostheses (AREA)

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• 2017
  • 2017-06-30 US US15/640,207 patent/US10274751B2/en active Active
  • 2017-07-05 KR KR1020197003239A patent/KR102407082B1/ko active Active
  • 2017-07-05 EP EP17739831.0A patent/EP3482251A1/en active Pending
  • 2017-07-05 WO PCT/US2017/040772 patent/WO2018009583A1/en not_active Ceased
  • 2017-07-05 JP JP2018568251A patent/JP7045337B2/ja active Active
  • 2017-07-05 MX MX2019000110A patent/MX395065B/es unknown
  • 2017-07-05 CN CN201780041824.5A patent/CN109477979B/zh active Active
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