MXPA96001680A - Designs of ring lens anular, concentrical for the astigmati - Google Patents

Abstract

Annular, concentric ring lens designs for astigmatic patients are described, particularly lens designs which reduce the patient's sensitivity to the misalignment of the toric axis, thus reducing the required number of units held in stock in the inventory for a toric product. Several of the annular, concentric ring lens designs comprise a concentric, multifocal annular ring design either on the front or back surface and a toric curve on the reverse surface to correct for astigmatism. The alternating concentric ring rings divide the optical zone of the contact lens into regions having at least two optical powers, a first optical power corresponding to the retracting spherical component of a basic Rx prescription of the patient and a second optical power corresponding to the cylindrical power of the basic Rx prescription of the patient, or a portion thereof, with an optional third intermediate optical power, such that the multiple focus toric lens is rotationally desensitized due to the increased focus depth provided by the plurality of rings concentric rings Some embodiments of the present invention have a spherical front or rear surface, wherein the opposite surface has a plurality of toric annular rings. Some embodiments of the present invention eliminate a toric surface, the characteristics of prism ballast and block displacement provide spherical optical powers in the spherical power Rx of basic prescription, the prescription Rx of cylindrical power and an intermediate optical power, intermediate to the optical and cylindrical powers.

Description

DESIGNS OF ANULAR RING LENS. CONCENTRIC FOR ASTIGMATISM BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates in general to annular ring lens designs, concentric for astigmatic patients and more particularly pertains to such lens designs, which reduce the patient's sensitivity to misalignment of the toric axis, thus reducing the required number of units maintained. in inventory warehouse (the total number of different prescriptions, which hold the deposit and can be prescribed) for a toric product. The present invention provides a novel approach to correct ametropia, such as astigmatism, hyperopia and myopia with the main correction for astigmatism. 2. Discussion of the Previous Technique Currently, toric lenses are manufactured in the prior art with the following design features:; to. a toric curve on the front or back surface of the lens; b. ballast prism characteristics and block displacement on the front surface of the lens; c. the non-toric surface is spherical. These prior art designs correct astigmatism appropriately, only if the axis of the cylindrical power is precisely aligned with respect to the axis of the astigmatic cornea. A misalignment of the axes (greater than 10 °) results in a substantial loss of visual acuity. The main force of this misalignment in soft hydrogel contact lenses is the poor rotational stability. In conventional prior art toric lens designs, a single toric surface comprising a main shaft and a secondary shaft is placed in the optical portion of either the front surface or the back surface of the lens. In addition, the axes of the toric lens are usually stabilized in relation to the corneas of the patient's cornea by the use either of a block displacement prism ballast characteristic or a double block displacement feature, placed on the front surface of the patient. the lens. These characteristics tend to increase the thickness of the resulting lenses and compromise comfort during use and physiological acceptability. In addition, conventional toric lens designs require a large number of units held in stock in inventory (the total number of different prescriptions, which are kept in the reservoir and can be prescribed) to fit a broad base of astigmatic patients. For example, the current Frequent Replacement Toric Lens products are available in 800 units maintained in stock per base curve in inventory (40 spherical powers X 2, two cylindrical powers X 10 cylindrical axis, different). Such a large number of units maintained in the tank per base curve in inventory is not economical to produce and maintain, particularly for a disposable-mode product. The large number of required maintenance units in the inventory warehouse is mainly due to the need to provide 10 or more different cylindrical shaft positions. In addition, any significant misalignment of the cylindrical axis with respect to the cylindrical axes of the eye, usually results in a significant loss of visual acuity. In an attempt to reduce the required number of cylindrical shaft fittings in units held in deposit, Australian Published Patent Application WO 93/03409 combines the aspheric surfaces with toric surfaces to accommodate axial misalignment through the depth of increased focus, provided by aspheres. The use of an aspherical surface increases the depth of field of the toric lenses and minimizes the effect of rotational misalignment of the toric lenses. Complex optical components such as optical diffraction components using diffraction gratings or birefringence optical components, they are also described by this published patent application. A disadvantage in using this approach of the prior art is the difficulty in manufacturing and controlling such complex optical components and spheres. Additionally with the aspheric optical components, it has been shown that anatomical variations of the patient produce compromised visual acuity. In summary, this prior art approach is undesirable, due to the high level of visual unpredictability of aspheric optical components in the real-world patient base, and due to the difficulty in manufacturing and controlling the aspheric optical components and other components complex optics.

BRIEF DESCRIPTION OF THE INVENTION Accordingly, it is a principal object of the present invention to provide annular ring lens designs, concentric for astigmatic patients, which reduce the patient's sensitivity to misalignment of the toric axis, thus reducing the required number of units held in storage, maintained in the inventory for a toric product. The present invention provides toric lens designs which reduce the number of cylindrical shaft fittings required to adapt astigmatic patients relative to conventional toric lens designs. Some embodiments of the present invention eliminate a toric surface, ballast prism characteristics and block elimination, provide spherical optical powers in the spherical power Rx of basic prescription, Rx of prescription of cylindrical power and an intermediate optical power between the optical powers spherical and cylindrical. Another object of the subject invention is the provision of annular ring lens designs, concentric for astigmatic patients, which comprises a concentric, multifocal annular ring design on either the front or rear surface and a toric curve on the reverse surface for correct astigmatism. The present invention uses alternating concentric ring rings, for dividing the optical zone of a contact lens in regions having at least two optical powers, a first optical power corresponding to the spherical component, refractive of a basic Rx prescription of the patient, and a second optical power corresponding to the cylindrical power of a basic Rx prescription of the patient, or a portion thereof. The present invention provides enhanced and enhanced visual acuity for astigmatic patients, using concentric annular ring lens designs for the correction of low levels of astigmatism and can also selectively use aspheric curves to increase vision for higher amounts of astigmatism. In accordance with the teachings herein, the present invention provides a concentric, multi-focus, annular ring lens for astigmatic patients, wherein one of the front and rear surfaces of the lens defines a toric curve and the other surface defines a plurality of concentric, spherical annular rings, having at least a first spherical annular ring corresponding to the basic, spherical Rx prescription of the patient and at least one second spherical annular ring corresponding to the patient's basic cylindrical Rx prescription , such that the multiple focus toric lens is rotationally desensitized, due to the increased depth of field, provided by the plurality of the concentric annular rings. In greater detail, the difference between the optical powers of the first and second spherical annular rings, is preferably less than 2.00 diopters. The second ring or rings, spherical, correspond to a portion of the prescription Rx cylindrical, complete. The design may also incorporate a third ring or annular, spherical rings corresponding to an intermediate optical power, which is between the optical powers of the first and second annular rings. The concentric annular rings surround a central disc that has the Rx prescription at a distance, basic spherical of the patient. In addition, an aspherical surface can be superimposed on the toric curve to increase the depth of field effect of the lens. The lens can be a contact lens, such as a soft hydrogel contact lens, or an intraocular lens. The present invention also provides a concentric, multi-focus, annular ring lens for astigmatic patients, wherein one of the front and rear surfaces defines a spherical or aspheric curve, and the other of the front and rear surfaces defines a plurality of concentric, spherical annular rings having at least one first spherical annular ring, corresponding to the prescription Rx at basic distance of the patient, and at least one second spherical annular ring which corresponds to the prescription cylindrical Rx of the patient. In greater detail, the second ring or spherical annular rings correspond to a portion of the complete cylindrical Rx prescription. The design may also incorporate a third ring or annular, spherical rings corresponding to an intermediate optical power, which is between the optical powers of the first and second annular rings. The first annular ring or rings, include a central disc having the Rx prescription at a distance, basic spherical of the patient, which is surrounded by at least a third annular ring of intermediate power, which is surrounded by at least one second annular cylindrical power ring. The concentric annular rings are preferably on the back surface of the lens and the front surface can define an aspheric curve to increase the depth of field effect of the lens. The present invention also provides a concentric, multi-focus annular ring lens for astigmatic patients in which one of the front and rear surfaces defines either a spherical or aspheric curve and the other surface defines a plurality respectively, of annular rings concentric or spherical concentric, having at least a first annular ring corresponding to the prescription Rx at a basic distance of the patient and at least one second annular ring corresponding to the prescription cylindrical Rx of the patient. In greater detail, the lens has a central portion with a remote optical power, an intermediate portion with a substantially equal division of optical power at a distance and cylindrical and an outer portion with an increased optical power at a distance. The optical powers between the first and second annular rings are preferably not greater than 2.00 diopters and the aspheric curve has an elliptical shape with a K value between -0.05 and -0.5, such that the ellipses are only slightly separated from the spheres . The present invention also provides a concentric, multi-focus, annular ring lens for astigmatic patients, wherein one of the front and top surfaces defines a spherical top corresponding to the spherical, basic prescribing distance of the patient and the other surface defines a plurality of concentric toric annular rings, having at least a first toric annular ring corresponding to the prescription Rx for correcting the spherical power at a basic distance of the patient and at least a second toric annular ring, corresponding to Cylindrical, basic prescription of the patient (combined spherical and cylindrical powers). In greater detail, the second annular or toric ring or ring corresponds to a portion of the complete cylindrical Rx prescription. The front surface defines the spherical surface and the back surface defines the plurality of toric annular rings, in which the optical power difference between the first and second concentric, alternating toric ring rings is not greater than 2.00D, which provides an effect of sufficient depth of focus, to allow axial misalignment of up to + or - 20 degrees of the axial reference position.

BRIEF DESCRIPTION OF THE DRAWINGS The aforementioned objects and advantages of the present invention for annular ring lens designs, concentric for astigmatism, 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 together with the accompanying drawings, in which similar elements are designated by identical reference numbers in all the various views, and in which: Figures 1 and 2 respectively illustrate the front and side planar views of a first embodiment of a ring lens annular, concentric, designed according to the teachings of the present invention, which comprises a spherical frontal surface of concentric annular ring, having first and second optical powers X and Y and a toric rear surface; Figures 3 and 4 illustrate respectively the front and side plan views of a second embodiment of a concentric annular ring lens, similar to the lens of Figures 1 and 2, which includes spherical, intermediate optical power I rings. the design of the lens, in addition to the first and second optical powers X and Y spherical; Figure 5 illustrates a plan view of the back surface of a third embodiment of an annular ring lens, concentric according to the present invention, which removes the toric surface and uses a spherical or aspherical surface on one side of the lens , combined with a spherical, concentric, multifocal ring ring surface on the opposite side of the lens; Figure 6 illustrates a plan view of the back surface of another embodiment of a lens design, which comprises a spherical front surface corresponding to the spherical, basic patient prescription and a toric posterior surface, consisting of ring, concentric ring ring surfaces, Figure 7 illustrates a preferred embodiment of the present invention, wherein the front surface of the lens comprises a simple toric curve in the optical zone, and the rear surface of the lens comprises spherical ring rings concentric, alternating, multiple; Figure 8 is a plan view of a preferred embodiment of a lens design, in which the optical zone of the lens is divided into three zones, an innermost zone, which is a spherical disc having the prescription Rx at a basic distance from the patient, a middle zone consisting of one or more annular rings having spherical and cylindrical optical powers, an outer zone consisting of one or more annular rings having predominantly cylindrical optical powers; Figure 9 is a plan view of the back surface of an exemplary embodiment of a lens, having a concentric multifocal back surface, either spherical or aspherical annular ring with either an aspheric or spherical front surface respectively; Figure 10 is a plan view of the front surface of an exemplary embodiment of a lens having a multifocal, concentric front surface, either with a spherical or aspherical annular ring, respectively with either an aspheric or spherical rear surface; Figure 11 shows a typical power profile for aspheric multifocal lenses and illustrates a graph of% spherical vision as a function of% pupil, in which greater percentages of the pupil correspond to greater radial distances from the optical zone of the lens .

DETAILED DESCRIPTION OF THE DRAWINGS Figures 1 and 2 illustrate, respectively, front and side plan views of a first embodiment of a concentric annular ring lens 10, designed in accordance with the teachings of the present invention, which comprises: a. a front, spherical concentric ring ring surface 12; b. a toric rear surface 14; c. features 16 of prism ballast and block displacement on the front surface. At first, the two spherical, optical powers X and Y of the ring, X, and Y rings, concentric of the frontal surface, alternating, can include first concentric annular rings that have spherical power that corresponds to the prescription Rx at basic distance of the patient and second rings spherical rings that correspond to the patient's cylindrical Rx prescription, which may correspond to a portion of the patient's cylindrical prescription. The resulting toric lens is rotationally desensitized in the same way as if the front surface were aspherical with a depth of field effect as described in Published Patent Application WO 93/03409. Figures 3 and 4 illustrate, respectively, front and side plan views of a second embodiment of an annular ring lens 20, concentric according to the present invention, similar to the first embodiment 10, in which, in addition to the two powers X and Y spherical, optical, spherical optical power rings I, intermediate are also included in the design of the lens. The following example is illustrative of the principles of the operation of the present invention, in the invention in the embodiments of Figures 1-4. For a patient with an Rx prescription of -3.00 / - 1.50 X 180 (where -3.00D is the patient's basic remote optical power correction, -1.50D is the correction of the patient's basic cylindrical optical power, with the cylindrical shaft specified at 180 °), the power on the axis of 90 ° -270 ° is -4.50D (which is the sum of -3.00D and -1.50D cylindrical, complete, available on this axis), while that the power on the 0-180 ° axis is -3.00D (the cylindrical surface does not contribute anything on this axis). For the first mode, the following are optical, spherical power values for x and y: x = -3.00D, y = -4.50D For the second mode, x = -3.00D, y = -4.50D and I = 3.75 D For In most patients, visual acuity is acceptable even if the refractive lens is displaced by 0.5D of the measured refractive power. Therefore, in the previous example, the effective ranges of the spherical optical powers are: In the first modality: -2.50D < x < -3.50D; -4.00D < and < -5.00D.

In the second modality: -2.50D < X < -3.50D; -4.00D < and < -5.00D; -3.25D < I < -4.25D.

It is recognized in the prior art that the brain of a patient has the ability to accommodate the acceptance of an image in focus while not considering the images out of focus. Recognizing the basic accommodation capabilities of the patient, the above prescriptions should provide acceptable visual acuity despite some misalignment (10 ° -20 °) of the axis of the toric lens. It is known that for astigmatic individuals, an astigmatic eye will form an image, which contains three main regions: 1. the spherical power will occur as a line; 2. The cylindrical power will also have focus as a line, perpendicular to the line of the spherical image. 3. a circular image will be focused between the two focal lines known as the "circle of least confusion", which is in an intermediate optical power, intermediate to the spherical and cylindrical optical powers. Figure 5 illustrates a plan view of the rear surface of a third embodiment of an annular ring lens 50, concentric according to the present invention, which eliminates the toric surface and also the characteristics of prism ballast and block displacement and uses a spherical or aspherical surface 52 on one side of the lens 50, preferably the front surface although the back surface can be used in alternative embodiments, combined with an annular, spherical, concentric multifocal ring surface 54 on the opposite side of the lens, preferably the back surface, although the front surface can be used in alternative modes. In this mode, the concentric ring rings in the optical zone of the lens provide at least three different optical powers: A - the spherical optical power of basic prescription, for the distance that exists along the cylindrical axis; B - the prescription of the cylindrical optical power (combined spherical and cylindrical powers); C - an intermediate optical power based on the best focal point or least confusing circle of a toric surface. This mode uses the principle of the adjustment of the equivalent, spherical optical power, together with the spherical and cylindrical optical powers. Various embodiments of the present invention achieve an increased depth of focus effect, without the use of aspheric surfaces and their concomitant complexities and disadvantages. Instead of spheres, concentric spheres or toric surfaces of small power difference between the alternating zones, they are used to provide an increased depth of focus effect. Figure 6 illustrates a plan view of the back surface of another embodiment of a lens design 60, which comprises a front, spherical surface 62 corresponding to the basic spherical distance prescription of the patient, a back surface 64, toric, consisting of concentric annular ring surfaces 66, having powers Pl and P2, alternating optics and a double block displacement feature 68 to stabilize the lens, either at a 90 ° or 180 ° axis position. The alternating concentric annular rings correspond to the prescription Rx of the patient and include first annular rings of power Pl corresponding to the prescription Rx at a distance of the patient and the second annular rings of a power P2 corresponding to the prescription Rx cylindrical of the patient, of preference a portion thereof. The difference in optical power between the annular, concentric, alternating annular rings Pl and P2 is not greater than 2.00D. This difference in power, small, provides a sufficient depth of focus effect to allow misalignment of the axis up to + or + 20 degrees from a reference, either as any of the 90 ° or 180 ° position. Figure 7 illustrates another preferred embodiment of the present invention, in which the front surface 72 of the lens 70, comprises a simple optical, toric zone 74, stabilized by a double block displacement feature 76 in the 90 ° position and 180 ° and the rear surface 78 of the lens comprises multiple alternating concentric spherical annular rings. The alternating concentric annular rings correspond to the prescription Rx of the patient and include first annular rings of power Pl that correspond to the prescription Rx of distance of the patient and second annular rings of a power P2 corresponding to the prescription Rx cylindrical of the patient, preferably a portion of it. Again, the difference in the power of the concentric, alternating spherical annular rings of the back surface is not greater than 2.00D, which allows misalignment of the axis up to + or + 20 degrees from the reference prescription position. In any of the two previous modalities, the number of units maintained in deposit per base curve, maintained in the inventory is reduced to 160 (40 spherical powers X 2 cylindrical powers X 2 axes -90 °, 180 °). In addition, the depth of focus effect provided by the concentric annular ring lenses allows axial misalignments without significant loss of visual acuity. Various embodiments of the present invention function by alternating spherical power with cylindrical power to provide adequate levels of both powers for the retina of the eye. The actual cylindrical power may be the full cylindrical power or any fraction thereof, in the range of 25% to 100% of the total refractive cylindrical power. In some preferred embodiments, the annular, concentric ring structures are placed on the back of the contact lens, with the basic spherical distance power on a disc at the center thereof. The following TABLE I illustrates various functionalities of the pupil, proposed for this type of multifocal annular ring lens design in which each zone may include a plurality of annular rings. The pupil of the individual is divided into three zones and the innermost zone is preferred as spherical.

TABLE I - Functions of the Preferred Pupil Inner Zone Middle Zone Outer Zone Type A: Sphere Equal Sphere (50/50 division) Type B: Equal Cylinder Sphere Type C: Equal Sphere Equal Type D: Sphere Cilindrica Sphere Type E: Equal Cylindrical Sphere In this table, cylindrical means a spherical optical power that corresponds to the cylindrical prescription (more spherical cylindrical powers), or a portion of it. Figure 8 is a plan view of this type of the design 80 of the lens, in which the optical zone of the lens, which corresponds to a pupil contracted or enlarged under various lighting conditions, is divided into three zones, one innermost zone 82, a middle zone 84, an outer zone 86, which are also illustrated in the embodiments of Figures 9 and 10. The innermost zone 82 is a spherical disc having the prescription Rx of the patient's basic distance. The middle zone 84 consists of one or more annular rings according to the above table, and the outer zone 86 also consists of one or more annular rings according to the table. Figure 8 illustrates a designed, exemplary embodiment of a lens design 100 of type B in the table, according to the present invention, having: an inner spherical zone S, surrounded by an intermediate zone having respective annular rings CSCS , surrounded by an outer zone having only cylindrical power, with a distance radius of 8.4 mm; a radius of near curve of 8.51173 mm; an intermediate curve radius of 8.39209 mm; and a peripheral curve radius of 9.832 mm.

The present invention relates to annular ring lens designs, concentric for the correction of astigmatism, which provides increased and improved visual acuity. Several of these lens designs have been clinically evaluated on an experimental basis and have been found to be effective in most cases up to cylindrical powers of -1.50 DC, with some positive effect up to -2.00 DC. The effectiveness of these lens designs can also be increased in the range of -1.50 DC to -2.00 DC by combining those annular ring lens designs, concentric with aspherical optical surfaces.

TABLE II - Types of Design Frontal surface Posterior surface Asfera Concentric spherical rings; Sphere Concentric aspherical rings; Spherical concentric rings; Concentric sphere aspherical rings Figure 9 is a plan view of the back surface of an exemplary embodiment of a lens 90, as listed in Table II, having either a spherical or aspheric, multifocal, concentric ring ring surface 92 with respectively, either an aspheric or spherical frontal surface 94. Figure 10 is a plan view of the front surface of an exemplary embodiment of a lens 100 as listed in Table II, having either a spherical or aspheric, multifocal, concentric annular ring surface 102, respectively, either with an aspherical or spherical posterior surface 104. The previous modalities of the present, divide the optical zone of the lens (which corresponds to different sizes of pupils) in discrete concentric zones with alternating cylindrical and alternating optical powers. The arrangement of these power zones could be placed to provide an optimal division between the spherical and cylindrical optical powers, obtained when the central portion of the lens has remote optical power, the pupils of intermediate size have an almost equal division and the sizes larger pupils that have an optical power at a distance, increased. The aspheric surfaces can be described by the following general equation, which is a general conical equation, which describes all the cones, including spheres, parabolas, ellipses and hyperbola: y = r + a - (+ l) ** where k = 0 for a sphere, k = -1 for a parabola, 0 > k > -1 for an ellipse, k < -1 for a hyperbola.

A lens with a front surface having an asphere combined with a back surface having concentric annular spherical rings is a preferred embodiment, since it is easy to design and implement. Most of the correction of the power difference for astigmatism is made by the design of the concentric annular ring lens and therefore, the asphere provides only a slight reinforcement that is required to improve visual acuity. To achieve this, a small aspheric K value is required. The K value is less than that required to reduce the diameter of the fuzzy circle (circle of least confusion) for both of the spherical and cylindrical powers by themselves. An optical form is an elliptical shape, with a K value between -0.05 and -0.5. In this way, the ellipses used in the present are only slightly separated from the spheres. In the case of the aspherical rings, either the spherical rings or the cylindrical rings, or both, can be aspherized. In this case, the K values also remain between -0.05 to -0.5. The present invention can also replace concentric, discrete annular bands with a uniform aspheric function. Aspheric in this sense may indicate a conical asphere, a conical asphere with variable eccentricity or a polynomial function, which simulates the discrete, functional power division. Figure 11 shows a typical power profile, as derived by such an aspherical surface, which could be either on the front or rear surface of the lens. Figure 11 illustrates a graph for aspheric multifocal lenses of% distance vision of sphere as a function of% of pupil, in which greater percentages of the pupil correspond to greater radial distances up to a radius that defines the outer circumference of the optical zone of the lens. Although various embodiments and variations of the present invention for concentric lens designs for astigmatism are described in detail herein, it should be apparent that the descriptions and teachings of the present invention will suggest many alternative designs for those skilled in the art. technique.

Claims (48)

NOVELTY OF THE INVENTION CLAIMS

1. An annular ring lens, concentric, of multiple focus for astigmatic patients, characterized because it comprises: a. the lens having a front surface of an opposite posterior surface; b. one of the front and rear surfaces defines a toric curve; c. the other of the front and back surfaces, defines a plurality of concentric, spherical annular rings, having at least one first spherical annular ring corresponding to the basic, remote, spherical prescription Rx of the patient and at least one second annular ring spherical corresponding to the basic cylindrical prescription Rx of the patient, in such a way that the multiple focus toric lens is rotationally desensitized, due to the increased depth of field, provided by the plurality of concentric annular rings.

2. The concentric annular ring lens of multiple focus for astigmatic patients according to claim 1, characterized in that the difference between the optical powers of the first and second spherical annular rings is less than 2.0 diopters.

3. The concentric ring lens of multiple focus for astigmatic patients according to claim 1, characterized in that at least one second spherical annular ring corresponds to a portion of the cylindrical, complete prescription Rx.

4. The ring-shaped, concentric, multi-focus annular lens for astigmatic patients according to claim 1, further characterized in that it includes at least a third spherical annular ring corresponding to an intermediate optical power, which is intermediate to the optical powers of the first and second ring rings.

5. The concentric annular ring lens of multiple focus for astigmatic patients according to claim 1, characterized in that the concentric annular rings surround a central disc having the prescription Rx at a basic spherical distance of the patient.

6. The multi-focus, concentric annular ring lens for astigmatic patients according to claim 1, characterized in that the concentric annular rings are on the posterior surface of the lens.

7. The multi-focus, concentric, annular ring lens for astigmatic patients according to claim 1, further characterized in that it includes an aspherical surface superimposed on the toric curve to increase the depth of field effect of the lens.

8. The ring, concentric, multi-focus ring lens for astigmatic patients according to claim 1, characterized in that the lens is a contact lens, such as a soft hydrogel contact lens.

9. The multi-focus, concentric, annular ring lens for astigmatic patients according to claim 1, characterized in that the lens is an intraocular lens.

10. The concentric annular ring lens, of multiple focus for astigmatic patients, characterized in that it comprises: a. the lens has a front surface and an opposite back surface; b. one of the front and rear surfaces defines a spherical or aspheric curve; c. the other of the front and rear surfaces defines a plurality of concentric, spherical annular rings, having at least a first spherical annular ring corresponding to the prescription Rx of basic distance of the patient and at least a second spherical annular ring, which corresponds to the cylindrical Rx prescription of the patient.

11. The multi-focus, concentric annular ring lens for astigmatic patients according to claim 10, characterized in that at least a second spherical annular ring corresponds to a portion of the full, cylindrical prescription Rx.

12. The multi-focus, concentric annular ring lens for astigmatic patients according to claim 10, further characterized in that it includes at least a third spherical annular ring corresponding to an intermediate optical power, which is between the optical powers of the first and second ring rings.

13. The multi-focus, concentric, annular ring lens for astigmatic patients according to claim 10, characterized in that the difference between the optical powers of the first and second spherical annular rings is less than 2.0 diopters.

14. The ring-shaped, concentric, multi-focus annular lens for astigmatic patients according to claim 13, characterized in that at least a first annular ring includes a central disc having the prescription Rx at a spherical, basic distance from the patient, at least a third annular ring surrounds the central disk and at least a second annular ring surrounds the third annular ring.

15. The multi-focus, concentric, annular ring lens for astigmatic patients according to claim 10, characterized in that the concentric annular rings are on the posterior surface of the lens.

16. The concentric ring lens of multiple focus for astigmatic patients, according to claim 10, characterized in that a surface defines an aspheric curve to increase the depth of field effect of the lens.

17. The multi-focus, concentric, annular ring lens for astigmatic patients according to claim 10, characterized in that the lens is a contact lens.

18. The multi-focus, concentric, annular ring lens for astigmatic patients according to claim 18, characterized in that the lens is a soft hydrogel contact lens.

19. The multi-focus, concentric, annular ring lens for astigmatic patients according to claim 1, characterized in that the lens is an intraocular lens.

20. An annular ring lens, concentric, of multiple focus for astigmatic patients, characterized because 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 curve; c. the other of the front and back surfaces, defines a plurality of concentric, aspherical annular rings, having at least one first aspherical annular ring corresponding to the remote, basic Rx prescription of the patient and at least one second aspheric ring which corresponds to the prescription cylindrical Rx of the patient.

21. The multi-focus, concentric, annular ring lens for astigmatic patients according to claim 20, characterized in that the lens has a central portion with a remote optical power, an intermediate portion with a substantially equal division of the optical power at a distance. and cylindrical and an outer portion with increased distance optical power.

22. The multi-focus, concentric, annular ring lens for astigmatic patients according to claim 20, characterized in that the spherical curve is on the front surface.

23. The multi-focus, concentric annular ring lens for astigmatic patients according to claim 20, characterized in that the optical powers between the first and second annular rings is not greater than 2.00 diopters.

24. The ring-shaped, concentric, multi-focus annular lens for astigmatic patients according to claim 22, characterized in that each aspheric ring has an elliptical shape with a K value between -0.05 and -0.5, such that the ellipses are only slightly separated from the spheres.

25. The multi-focus, concentric, annular ring lens for astigmatic patients according to claim 20, characterized in that at least one second annular ring corresponds to a portion of the complete cylindrical prescription Rx.

26. The ring-shaped, concentric, multi-focus ring lens for astigmatic patients according to claim 20, characterized in that the concentric annular rings surround a central disc having the prescription Rx of basic spherical distance of the patient.

27. The multi-focus, concentric, annular ring lens for astigmatic patients according to claim 20, characterized in that the lens is a contact lens.

28. The multi-focus, concentric, annular ring lens for astigmatic patients according to claim 27, characterized in that the contact lens is a soft hydrogel contact lens.

29. The multi-focus, concentric annular ring lens for astigmatic patients according to claim 20, characterized in that the lens is an intraocular lens.

30. The ring lens, concentric, multiple focus 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 an aspheric curve; c. the other of the front and back surfaces, defines a plurality of concentric, spherical annular rings, having at least a first spherical annular ring corresponding to the prescription Rx of the basic distance of the patient and at least a second spherical annular ring which corresponds to the prescription cylindrical Rx of the patient.

31. The multi-focus, concentric, annular ring lens for astigmatic patients according to claim 30, characterized in that the lens has a central portion with a remote optical power, an intermediate portion with a substantially equal division of the optical power at a distance. and cylindrical and an outer portion with remote optical power, increased.

32. The ring-shaped, concentric, multi-focus ring lens for astigmatic patients according to claim 30, characterized in that the aspheric curve is on the front surface.

33. The multi-focus, concentric annular ring lens for astigmatic patients according to claim 30, characterized in that the optical powers between the first and second annular rings is not greater than 2.00 diopters.

34. The ring-shaped, concentric, multi-focus annular lens for astigmatic patients according to claim 32, characterized in that each aspheric ring has an elliptical shape with a K value between -0.05 and -0.5, such that the ellipses are only slightly separated from the spheres.

35. The multi-focus, concentric ring annular lens for astigmatic patients according to claim 30, characterized in that at least one second annular ring corresponds to a portion of the complete cylindrical prescription Rx.

36. The ring-shaped, concentric, multi-focus ring lens for astigmatic patients according to claim 30, characterized in that the concentric annular rings surround a central disc having the prescription Rx of basic spherical distance of the patient.

37. The multi-focus, concentric, annular ring lens for astigmatic patients according to claim 30, characterized in that the lens is a contact lens.

38. The multi-focus, concentric, annular ring lens for astigmatic patients according to claim 37, characterized in that the contact lens is a soft hydrogel contact lens.

39. The multi-focus, concentric annular ring lens for astigmatic patients according to claim 30, characterized in that the lens is an intraocular lens.

40. The ring lens, concentric, multiple focus 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 an aspheric surface corresponding to the patient's basic spherical distance prescription; c. the other of the front and back surfaces, defines a plurality of concentric toric annular rings, having at least a first toric annular ring corresponding to the prescription Rx of the basic spherical correction of the patient and at least a second annular ring toric corresponding to the cylindrical, basic prescription of the patient.

41. The multi-focus, concentric annular ring lens for astigmatic patients according to claim 40, characterized in that the difference in optical power between the first and second concentric, alternating toric annular rings is not greater than 2.00D, which provides a sufficient depth of focus effect to allow axial misalignment of up to + or - 20 degrees from the reference axial position.

42. The multi-focus, concentric annular ring lens for astigmatic patients according to claim 41, characterized in that at least a second toric annular ring corresponds to a portion of the complete, cylindrical prescription Rx.

43. The multi-focus, concentric, annular ring lens for astigmatic patients according to claim 40, characterized in that the front surface defines the spherical surface and the back surface defines the plurality of toric annular rings.

44. The multi-focus, concentric ring annular lens for astigmatic patients according to claim 40, characterized in that at least a second toric annular ring corresponds to a portion of the complete cylindrical prescription Rx.

45. The ring-shaped, concentric, multi-focus ring lens for astigmatic patients according to claim 40, characterized in that the concentric annular rings surround a central disc having the prescription Rx of basic spherical distance of the patient.

46. The ring-shaped, concentric, multi-focus ring lens for astigmatic patients according to claim 40, characterized in that the optical powers between the first and second annular rings is not greater than 2.00 diopters.

47. The ring-shaped, concentric, multi-focus annular lens for astigmatic patients according to claim 40, characterized in that each toric annular ring has an aspheric curve having an elliptical shape with a K value between -0.05 and -0.5, in such a way that the ellipses are only slightly separated from the spheres.

48. The concentric ring lens of multiple focus for astigmatic patients according to claim 40, characterized in that the lens is a contact lens, such as a soft hydrogel contact lens. DESIGNS OF ANULAR RING LENS, CONCENTRIC FOR ASTIGMATISM SUMMARY OF THE INVENTION Annular, concentric ring lens designs for astigmatic patients are described, particularly lens designs which reduce the patient's sensitivity to misalignment of the toric axis, thus reducing the required number of units held in stock in the inventory for a toric product. Several of the concentric annular ring lens designs comprise a concentric, multifocal annular ring design on either the front or rear surface and a toric curve on the reverse surface to correct astigmatism. The alternating concentric annular rings divide the optical zone of the contact lens into regions having at least two optical powers, a first optical power corresponding to the retracting spherical component of a basic Rx prescription of the patient and a second corresponding optical power. to the cylindrical power of the basic prescription Rx of the patient, or a portion thereof, with a third intermediate, optional optical power, such that the multiple focus toric lens is rotationally desensitized due to the increased depth of focus, provided by the plurality of concentric annular rings. Some embodiments of the present invention have a spherical front or rear surface, wherein the opposite surface has a plurality of toric annular rings. Some embodiments of the present invention eliminate a toric surface, the properties of prism ballast and block displacement and provide spherical optical powers in the spherical power Rx of basic prescription, the prescription Rx of cylindrical power and an intermediate optical power, intermediate to the optical powers spherical and cylindrical.