MXPA96001667A - Designs of torica lens, aesfer - Google Patents

Abstract

O-ring, aspherical lens designs are described, which reduce the number of cylindrical shaft locations required for inventory holding units, by aspherization of their toric surface. The present invention pertains to contact lenses such as hydrogel, soft contact lenses, designed particularly for adapting to astigmatic patients, who are either presbyopic or non-presbyopic. One of the front and rear surfaces of the aspheric toric lens defines a spherical surface corresponding to at least the prescription Rx at the patient's basic distance. The other of the front and rear surfaces defines a toric, aspheric curve, in which the toric surface is constructed with aspheric radii, in such a way that the aspheric curve desensitizes the axial misalignment of the toric curve, providing an increased depth of focus . When the aspheric toric surface is on the back surface of the lens, the spherical curve on the front surface of the lens may consist of a single spherical curve corresponding to the prescription Rx at the patient's basic distance. When the aspheric curve is on the front surface of the lens, the spherical curve on the back surface of the lens may consist of a concentric, multi-focus, ring-shaped spherical surface design.

Description

DESIGNS OF TORICA LENS, AESPHERIC BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates in general to toric, aspheric lens designs. More particularly, the subject invention pertains to toric, aspherical lens designs, which reduce the number of positioning orientations of the cylindrical shaft, required to maintain units in deposit, maintained in the inventory by aspherization of their toric surface. The present invention relates to aspheric, aspheric, lens designs, which reduces the number of units held in stock in inventory, which are required to adapt astigmatic patients, who are either presbyopic or presbyopic. 2. Discussion of the Previous Technique The present invention pertains to ophthalmic lenses and in particular to contact lenses, such as hydrogel, soft contact lenses and intraocular lenses having more than one optical power or focal length and in particular toric lenses. Current toric lens designs use spherical beams to build the toric surface. The prior art toric lens designs correct astigmatism, but require many different orientations of the cylindrical axis for different units kept in storage, maintained in the inventory (the total number of different possible prescriptions held in the inventory), which results disadvantageous in a large number of units kept in the warehouse, kept in the inventory. In conventional toric lens designs, an individual toric surface is placed in the optical portion of either the front or rear surface of the lens. The other surface of the lens is typically spherical and corresponds to the correction of the basic spherical distance of the patient's prescription. The axes of the toric lens are usually stabilized relative to the axis of the patient's cornea by the use of either the ballast prism / block displacement characteristics or double block displacement placed on the front surface of the lens. Conventional toric lens designs require a large number of units maintained in the depot in inventory to adjust the basis of the astigmatic patient. For example, the Frequently Replaceable O-ring lens products, current for non-presbiops, are available in 800 tank holding units (40 spherical powers X 2 cylindrical powers X 10 cylindrical axis orientations). To provide such lenses for the presbiopes, the units that are kept in deposit have to be multiplied by the number of added powers. Such a large number of units maintained in the warehouse are not economical to produce and maintain inventory, particularly in a disposable-mode product. The large number of units maintained in the tank increases mainly from the need to provide multiple cylindrical shaft orientations, cylindrical powers and aggregate powers. In an attempt to reduce the required number of cylindrical shaft fittings in the units that are held in deposit, Australian Patent Application WO 93/03409 combines the aspheric surfaces with toric surfaces to accommodate axial toroidal misalignment through the depth of increased focus, provided by the asieras. The use of the aspheric surface increases the depth of field of the toric lenses and minimizes the rotational misalignment effect of the toric lenses. Complex optical components such as optical diffraction components using optical diffraction grating or birefringence components are also described by this published patent application. This patent application does not address the need to or allow the combination of a toric lens product having a low number of units held in the tank, with a multifocal surface to correct the presyopic astigmatism, which is a main advantage of the present invention, over that. It is well known that as an individual ages, the eye is less able to accommodate, ie, flex the natural lens in the eye, to focus on objects that are relatively close to the observer. This condition is mentioned as presbyopia and the presbiopes have been packaged in the past in glasses or other lenses that have many different regions with different optical powers, to which the user can move his vision to find the appropriate optical power for the object or objects upon which the observer wishes to focus. Patent Application Serial No. 07 / 988,088 attorney's file VTN 56), entitled PUPIL TUNED MULTIFOCAL OPHTHALMIC LENS, discloses a concentric, multifocal ophthalmic lens for presbyopic patients, constructed with three general annular lens portions in a multifocal design. A circular central portion of the lens has only the corrective power of the patient's distance and is surrounded by a first, inner, annular portion, which may consist of multiple annular rings, having an inner radial portion, which increases the focal power close to the patient, surrounded by radial portions of variable cumulative amounts of the focal correction of the remote and near optical power for the patient. This is surrounded by a second, outer, annular portion, which also consists of one or more annular rings having focal power at an additional distance, close to the periphery of the optical surface area of the ophthalmic lens. Each annular ring has either a remote or near optical power and works in combination with other portions of the lens to produce the desired focal ratio in this portion of the lens.

BRIEF DESCRIPTION OF THE INVENTION Accordingly, it is a principal object of the present invention to provide toric, aspheric lens designs, which reduce the number of cylindrical shaft locations required for the units maintained in the tank, in inventory by aspherization of its toric surface. The present invention pertains to ophthalmic lenses, and in particular to contact lenses, such as soft hydrogel contact lenses, particularly designed to in astigmatic patients who are either presbyopic or non-presbyopic. Another object of the invention is the provision of toric contact lens designs, in which the toric surface is constructed with the use of aspheric radii instead of spherical spokes as in the prior art. In accordance with the teachings herein, the present invention provides an aspheric toric lens for astigmatic patients, wherein one of the front and rear surfaces defines a spherical surface. The other of the front and rear surfaces defines an aspheric toric curve, in which the combination of the spherical surface and the toric curve corresponds to at least the prescription Rx of basic distance of the patient and in which the toric surface is constructed with Aspherical radii, in such a way that the aspheric curve sensitizes the axial misalignment to the toric curve, providing an improved depth of focus. In greater detail, the aspheric curve may consist of an elliptical curve, or a parabolic curve, or a hyperbolic curve. The aspheric toric surface can be on any of the rear or front surface of the lens. The aspheric curve may consist of a single spherical curve, or a spherical surface design of the concentric annular ring, of multiple focus, having a circular, central spherical disc corresponding to the prescription Rx of basic spherical distance of the patient, at least an annular spherical ring corresponds to the prescription Rx of basic spherical distance of the patient, and at least one annular spherical ring corresponding to the close, spherical prescription Rx of the patient, in which the design of concentric annular ring, multiple focus corrects Presbyopia and also improves the depth of focus of the toric curve. The lens may consist of a contact lens, such as a soft hydrogel, or an intraocular lens.

BRIEF DESCRIPTION OF THE DRAWINGS The above objects and advantages of the present invention, for toric, aspherical lens designs, can be more readily understood by one skilled in the art, reference being made to the following detailed description of several of its preferred embodiments, taken in conjunction with the drawings. annexes in which like elements are designated by identical reference numbers in all the various views, and in which: Figure 1 illustrates a plan view of the rear surface of a first embodiment of a toric lens design, aspheric in accordance with the present invention, which comprises a back surface as illustrated, consisting of an aspheric toric source in an axial position of 180 degrees and a spherical front surface corresponding to the basic spherical prescription Rx of the patient; Figure 2 illustrates a potential asphericization effect of the toric surface and illustrates in dotted lines, a toric surface with a spherical cross-section on the main and secondary axes of the toric surface and also illustrates in solid lines, a toric surface with a cross section aspherical transverse on the main and secondary axes of the toric surface; Figure 3 illustrates a plan view of the front surface of a second embodiment of an aspheric, toric lens design for presyopic astigmatic patients, in accordance with the present invention, which comprises a front surface for astigmatic correction consisting of an aspheric toric surface in an axial position of 90 degrees, and a posterior surface for the presbyopic correction, which comprises a concentric annular ring design, of multiple focus corresponding to the prescription Rx of remote correction and near spherical, basic patient; Figure 4 illustrates a plan view of the back surface of the second embodiment of Figure 3, which provides the presyopic correction and comprises a concentric annular, multiple focus ring design corresponding to the remote correction prescription Rx and Close, spherical, basic patient.

DETAILED DESCRIPTION OF THE DRAWINGS The present invention relates to toric, aspherical lens designs, which aspherizes the toric surface of the lens in a form that allows the aspherical shape to eliminate the requirement for cylindrical axis orientations, multiples, cylindrical powers and aggregate powers. Figure 1 illustrates a plan view of the rear surface of a first embodiment of an aspheric toric lens design 10 according to the present invention, which comprises a rear surface 12 as illustrated, consisting of a toric surface 14 , aspherical in an exemplary 180-degree axis position and a spherical frontal surface 16, not illustrated in detail, which corresponds to the patient's basic, spherical Rx prescription.

The toric surface 14 can be described by the following general aspheric equation, which can be used to calculate each of the main meridians of the lens: cy X 1 + l -c2y2 (k + 1) where c is the apex of curvature, and is the distance of the axis (semicuerda), k is the conic constant, where k = 0 = sphere, k = -1 = parabola, -l < k < 0 = ellipse, + k, -1 = hyperbola. A double-elimination block feature 18 is incorporated to stabilize the axes of the aspheric toric curve on the rear surface of the lens, either at a 90 degree or 180 degree axis position. In an alternative embodiment, the aspheric toric surface may be placed on the rear or rear side of the lens and the spherical curve placed on the front or front side of the lens. The shape of the sphere, which is superimposed on the toric surface, can be designed based on the elimination of aberrations of the lens and eyepieces or by the optimization of the quality of the retinal image (MTF). The aspheric toric surface is constructed with the use of aspheric spokes instead of spherical spokes as in the prior art and provides a sufficient depth of focus effect to allow misalignment of the cylindrical axis of up to + or -20 degrees, of the positions of 90 degrees or 180 degrees, and can correct astigmatism up to -2.00D with a lower cylindrical power (for example, 1.50D). Figure 2 illustrates the effect of asphering the toric surface and illustrates on the dotted line 20 a toric surface with a spherical cross-section on the main axis and on the dotted line 22 a toric surface with a spherical cross-section on the secondary axis of the toric surface. Figure 2 also illustrates on the solid line 25, a toric surface with an aspheric cross section on the main shaft and illustrates on the solid line 26 a toric surface with an aspheric cross section on the secondary axis of the toric surface. For negative eccentricity values, the effective cylinder will decrease from the center of the lens to the periphery of the optical zone, since more positive is added as a function of the radial distance. Figure 3 illustrates a plan view of the front surface of a second embodiment of a toric lens design 30, aspheric for astigmatic, presbyopic patients according to the present invention, which comprises a front surface 32 for astigmatic correction, which consists of a toric, aspherical surface 34 in an exemplary position of the axis at 90 degrees and a posterior surface 36 for presbyopic correction, which comprises a concentric annular, multiple focus ring design corresponding to the correction prescription Rx near and spherical distance, basic of the patient. In the second modality, to correct presbyopia in the astigmatic population, the aspheric toric surface is placed on the front or anterior surface of the lens and a concentric annular ring of multiple focus is placed on the posterior or posterior surface. Again, the depth of focus effect of the asphere will correct up to 2.00D aggregates with a lower aggregate power (eg, 1.50D). Figure 4 illustrates an exemplary embodiment of a back surface 36 of the concentric, multifocal ring and shows only the optical zone of the lens, which would correspond in size to the size of the toric surface 34 and is normally surrounded by a lenticular portion (non-optical ) of the lens, which is not shown in Figure 4. The back surface of the concentric, multifocal ring provides the presyopic correction and includes a central area 12 of the lens 40, which is a circular disc containing the remote power. spherical, prescribed Rx, basic and is surrounded by a plurality of ring rings 42, 44, 46, 48, 50 and 52 of spherical distance power and of spherical close power, alternating. The central circular portion 42 of the lens has only the corrective power at a distance from the patient, to provide the corrective power remotely under conditions of high illumination (when the pupil is contracted). This is surrounded by a relatively wide first annular ring 42 to provide an increased contribution of near vision optical power, to provide an approximately equal amount of distance and near focal length images under intermediate light conditions. This is surrounded by alternating near and far annular rings 44, 46, 48 and 50, providing substantially equal cumulative amounts of close and distant optical power correction to the patient. This is surrounded by an outer annular ring 52 having an additional, remote focal power, near the periphery of the optical surface area of the ophthalmic lens to provide remote optical power, improved under low light conditions. A typical contact lens is usually constructed with a non-optical lenticular area (not shown) outside the optical surface for a total diameter of about 14 mm. The present invention allows a significant reduction in the number of units maintained in stock in inventory, required to adjust the same population of astigmatic and non-presbyopic presbiops as shown by the following TABLE: TABLE Conventional Toric Components: Spheres (-6D to + 4D, in stages of 0.25D) = 40 Cylinders (-1.25D, -2.00D) = 2 Axes (90, 180 +/- 20 in stages of 10 degrees) = 10 Additions (none, 1.25D, 2.00D) = 3 TOTAL = 2400 The Present Invention: Spheres (-6D to + 4D, in stages of 0.25D) = 40 Cylinders (-1.50D) = 1 Axes (90, 180) = 2 Additions (none, 1.50D) = 2 TOTAL = 160 The present invention desensitizes the requirements of many cylindrical shaft locations, required for units held in stock in the inventory by the aspherization of their toric surface. Different modalities of bars for use in the present invention include conical bars, including ellipses, parabolas and hyperbolas. The asieras can be achieved by empirical trial and error or by the use of in vivo modulation transfer function (MTF) devices, which can help in identifying and reducing aberrations. The result of this will be toric lenses with decreased requirements of a large number of units kept in stock in the inventory and to provide patients with improved visual acuity. The present invention can be initiated with aspheric toric lens designs, possibly combined with multifocal annular ring lens designs, as illustrated in Figures 1-4, and then use the in vivo image quality analysis equipment, such as an aberroscope or an MTF point dissemination apparatus, to evaluate, identify and quantify any of the residual aberrations of the lens in place over the patient's eye. These residual aberrations can then be further reduced by modifying the design of the lens, such as by modifying the lens sawing to improve visual acuity and performance. From this, the present invention provides an improvement in the operation of the designs for spherical ametropia, presbyopia or astigmatism, which is realized by a reduction of the aberrations of the combination of the lens and the eye system. The reduction in aberrations does not correct ametropia by itself. First, an individual (or population) is adapted with a concentric lens, and then the individual (or population) is tested with an in vivo image quality device, to determine the residual aberrations with the lenses placed in the eye. Next, the lens is redesigned to reduce the measured residual aberrations. Obviously, many different embodiments of the present invention are possible, with alterations of the type of aspheric toric curve, or by the number of annular rings, the widths and arrangements of the annular rings, etc. Although various embodiments and variations of the present invention for designs of an aspheric toric lens are described in detail herein, it should be apparent that the description and teachings of the present invention will suggest many alternative designs for those skilled in the art.

Claims (13)

NOVELTY OF THE INVENTION CLAIMS

1. A toric, aspherical lens for astigmatic patients, characterized in that it comprises: a. the lens having a front surface and an opposite rear surface; b. one of the front and rear surfaces defines a spherical surface; c. the other of the front and rear surfaces defines a toric, aspheric curve in which the combination of the spherical surface and the toric curve corresponds to at least the prescription Rx at basic distance of the patient and in which the toric surface is constructed with aspherical radii, in such a way that the aspheric curve desensitizes the axial misalignment of the toric curve providing an increased depth of focus.

2. The toric, aspheric lens for astigmatic patients according to claim 1, characterized in that the aspheric curve comprises an elliptical curve.

3. The toric, aspheric lens for astigmatic patients according to claim 1, characterized in that the aspheric curve comprises a parabolic curve.

4. The toric, aspheric lens for astigmatic patients according to claim 1, characterized in that the aspheric curve comprises a hyperbolic curve.

5. The toric, aspheric lens for astigmatic patients according to claim 1, characterized in that the aspheric toric surface is the posterior surface of the lens.

6. The toric, aspheric lens for astigmatic patients according to claim 1, characterized in that the aspheric toric surface is the front surface of the lens.

7. The toric, aspheric lens for astigmatic patients according to claim 1, characterized in that the spherical surface comprises a single spherical curve.

8. The toric, aspheric lens for astigmatic patients according to claim 1, characterized in that the spherical surface of the lens comprises a spherical concentric annular ring design, of multiple focus having a circular, central spherical disc corresponding to the prescription Rx a basic spherical distance of the patient and at least one annular spherical ring corresponding to the spherical, basic Rx prescription of the patient and at least one annular spherical ring corresponding to the close, spherical Rx prescription of the patient in which the Multi-focus concentric annular ring design corrects presbyopia and also increases the depth of focus of the toric curve.

9. The toric, aspheric lens for astigmatic patients according to claim 1, characterized in that the lens comprises a contact lens.

10. The toric, aspherical lens for astigmatic patients according to claim 9, characterized in that the contact lens comprises a soft hydrogel contact lens.

11. The toric, aspheric lens for astigmatic patients according to claim 1, characterized in that the lens comprises an intraocular lens.

12. A method for designing a toric, aspherical lens for astigmatic patients, characterized in that it comprises: a. the lens having a front surface and an opposite rear surface; b. one of the front and rear surfaces defines a spherical surface; c. the other of the front and rear surfaces defines a toric, aspheric curve in which the combination of the spherical surface and the toric curve corresponds to at least the prescription Rx at basic distance of the patient and in which the toric surface is constructed with aspheric radii, in such a way that the aspheric curve desensitizes the axial misalignment of the toric curve providing an increased depth of focus; d. perform an in vivo image quality analysis with an in vivo quality analysis instrument of the lens in the eye to measure any of the residual aberrations, e. reduce measured residual aberrations, redesigning the lens to improve visual quality and performance.

13. The method of designing a lens according to claim 12, characterized in that the redesign of the lens includes redesigning the aspheric curve of the aspheric toric curve. DESIGN OF TORICA LENS, AESPHERIC SUMMARY OF THE INVENTION O-ring, aspherical lens designs are described, which reduce the number of cylindrical shaft locations required for inventory holding units, by aspherization of their toric surface. The present invention pertains to ophthalmic lenses, and in particular to contact lenses such as hydrogel, soft contact lenses, particularly designed to fit astigmatic patients, who are either presbyopic or non-presbyopic. One of the front and rear surfaces of the aspheric toric lens defines a spherical surface corresponding to at least the prescription Rx at the patient's basic distance. The other of the front and rear surfaces defines a toric, aspheric curve, in which the toric surface is constructed with aspheric spokes, in such a way that the aspheric curve desensitizes the axial misalignment of the toric curve, providing a depth of focus increased. When the aspheric toric surface is on the posterior surface of the lens, the spherical curve on the front surface of the lens may consist of a single spherical curve corresponding to the prescription Rx at the patient's basic distance. When the aspheric toric curve is on the front surface of the lens, the spherical curve on the rear surface of the lens may consist of a concentric ring, spherical surface design of multiple focus.