MXPA96001679A - Multifocal lens designs with opticalintermed powers - Google Patents

Abstract

A concentric, multi-focus annular ring lens in which one of the front and rear surfaces of the lens defines a central area comprising a circular disk having a spherical surface, corresponding to a remote, spherical optical power of basic prescription Rx. A plurality of annular rings surround the central area and have alternating spherical remote and near optical powers and at least one annular ring of intermediate optical power is located in the middle or outer region of the optical zone of the lens and its optical power is intermediate to the remote optical powers. and close, to provide visual acuity at intermediate distances. The ring of intermediate optical power can be placed on either side in the middle or outer region of the optical zone of the lens and can be the second annular ring from the outer edge of the optical zone of the lens, or it can be the outermost annular ring which defines the outer circumference of the optical zone of the lens. The lens can be a contact lens to be used on the cornea of the eye, such as a soft hydrogel contact lens or it can be an intraocular lens.

Description

MULTIFOCAL LENS DESIGNS WITH INTERMEDIATE OPTICAL POWERS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to multifocal lens designs, with intermediate optical powers and more particularly belongs to the designs of the multifocal lens with intermediate optical powers, which provides visual acuity at intermediate distances by adding one or more annular rings of power optical, intermediate for a concentric, multifocal annular ring lens. 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. 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 presbyopia in the past have been based on glasses or other lenses that have many different regions with different optical powers, to which the user can shift his vision to find the appropriate optical power for the object. objects on which the observer wishes to focus. With the goggles of the process it involves shifting one's field of view from typically a portion of the far superior power lens to a portion of the lower lens of near power. However, with hydrogel or soft contact lenses, this approach has been less than satisfactory. The contact lens, working together with the natural lens, forms an image on the retina of the eye focusing the incident light on each part of the cornea of different field angles on each part of the retina to form an image. This is demonstrated by the fact that as the pupil contracts in response to brighter light, the image on the retina does not contract, but instead, light comes through a smaller area of the lens to form the complete image. Similarly, for a person who has had the natural lens of the eye removed, due to the condition of cataracts and an inserted intraocular lens as a replacement, the ability to adjust the lens (accommodate) to the distance of the object being observed, It is totally absent. In this case, the usually provided lens establishes a focal power of individual infinite distance and the glasses are used to provide the additional positive optical power needed for the closest vision in focus. For such a patient, the functional multifocal lens would be particularly useful. It is also known in the art that under certain circumstances, the brain can discriminate between competing images separately, accepting an image in focus and rejecting an out-of-focus image. An example of this type of lens used for the correction of presbyopia providing simultaneous near and far vision is described in U.S. Patent 4,923,296 to Erickson. This patent describes a lens system, which comprises a pair of contact lenses, each having equal areas of near and distant optical power, with the lens for an eye having a close upper half and a distant lower half and the lens for the other eye that has a distant upper half and a lower lower half nearby. Together they can provide at least clear, partial images in both eyes and by suppressing blurry images by the brain, allowing the alignment of clear images to produce an image in focus. U.S. Patent 4,890,913 to Carie discloses a bifocal contact lens, which comprises many annular zones having different optical powers. The object in the design of this lens is to maintain, all the times without considering the diameter of the pupil, an approximately equal division between the near and distant powers, which requires between six and twelve total zones on the lens. Another attempt to provide a bifocal contact lens is described in U.S. Patent 4,704,016 to Carie. Again, this lens tries to maintain, at all times without considering the diameter of the pupil, an approximately equal division between the near and distant powers. Patent Application Serial No. 07 / 988,088 (file of the proxy VTN 56), entitled PUPIL TUNED MULTIFOCAL OPHTHALMIC LENS, describes a concentric, multifocal ophthalmic lens for presbyopic patients constructed with three general annular lens portions in a multifocal design. A central circular portion of the lens has only corrective power of the patient's distance and is surrounded by a first inner annular portion, which consists of multiple annular rings having an inner radial portion, which improves the close focal power of the surrounded patient by radial portions of substantially equal cumulative amounts of remote and near optical power focal correction for the patient. This is surrounded by a second annular, outer portion which also consists of one or more annular rings having additional, distant focal power near the periphery of the optic surface area of the ophthalmic lens. Each annular ring has either near or distant optical power and works in combination with other portions of the lens to produce the desired focal ratio in that portion of the lens. Trifocal eyeglasses are also known in the prior art, in which a portion of the eyeglass lens, upper has a prescription for far vision, a portion of the lens of the eyeglasses, lower has a prescription for near vision and A portion of the eyeglass lens, intermediate positioned between the portions of the upper and lower lens, has a prescription for intermediate vision. In addition, mixed trifocal and multifocal spectacles are also known, in which a portion of the upper lens has a prescription for far vision and a portion of the lower lens has a prescription for near vision and a portion of the lens, intermediate it has a mixed prescription which changes gradually from the optical power for the upper portion to the optical power for the lower lens portion. However, these concepts are not easily extended to contact or intraocular lenses, since a user can not shift their vision through different upper and lower areas of a contact or intraocular lens. The only change that the eye makes with respect to a contact or intraocular lens is an involuntary control in the diameter of the pupil, which decreases in bright light and increases in weak light.

BRIEF DESCRIPTION OF THE INVENTION Therefore, an object of the present invention is to provide an ophthalmic lens for a presbiope that produces improved visual acuity in general and in particular, meets the focal requirements of intermediate distance conditions. The present invention provides a contact or intraocular lens, which couples the distribution of near, intermediate and distance focal vision corrections for the type of human activity normally carried out under various lighting conditions. The present invention also couples the particular dimensions of a contact lens to suit the size of the user's pupil as a function of the intensity of illumination. The ophthalmic lens is designed to provide predominantly remote correction under high illumination, remote and near corrections almost evenly divided under moderate illumination and provide intermediate vision correction under low to moderate illumination levels. The lens is also specifically designed to match the size of the user's pupil as a function of the level of illumination and in preferred embodiments, it can also apply the parameters of the pupil size as a function of the user's age. Accordingly, it is a principal object of the present invention to provide multifocal lens designs with intermediate powers, which address the problem of optical, intermediate distance vision by adding one or more annular rings of optical power, intermediate to a ring lens. annular, concentric, multifocal. A preferred intermediate optical power is substantially 50% of the aggregate difference between the remote power and the near power, otherwise it could be chosen to be any optical power between the optical powers of distance and near.

In accordance with the teachings herein, the present invention provides a multi-focus, concentric annular ring lens in which one of the front and back surfaces of the lens defines a central area, comprising a circular disk having a surface spherical that corresponds to a remote optical power, spherical, of basic Rx prescription. A plurality of annular rings that surround the central area and have close optical powers, spherical and remote optical powers, alternating spherical and at least one annular ring of intermediate optical power. The annular ring of intermediate optical power can be located in the outer region of the optical zone of the lens and its optical power is intermediate to the optical powers at a distance and near, to provide visual acuity at intermediate distances. In more detail, the annular annular ring or rings of intermediate optical power, may be placed in the outer radial portion of the optical zone, where an annular ring may be in that portion, or it may consist of the outer, full radial portion or it may be placed in the middle radial portion, where it is preferably placed on its outer edge, or it can be placed on any other side in that portion. The lens can be a contact lens for use in the cornea of the eye, such as a soft hydrogel contact lens or it can be an intraocular lens. The central area and the plurality of annular rings are preferably formed on the rear surface of a contact lens, to minimize reflection and brightness problems. In addition, the widths of the individual annular rings may be different to generate a power profile, which varies to generate different optical power ratios at distance to intermediate and near optical power.

BRIEF DESCRIPTION OF THE DRAWINGS The objects and advantages mentioned in the foregoing of the present invention, for designs of the multifocal lens with intermediate optical powers, can be more easily 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 like elements are designated by identical reference numbers in all the various views, and in which: Figure 1 is a plan view of a first embodiment of a multifocal lens design having an intermediate optical power, in which an annular ring of intermediate optical power is the outermost annular ring in the middle portion of the optical zone of the lens; Figure 2 is a plan view of a second embodiment of a multifocal lens design, having an intermediate optical power, in which the annular ring of intermediate optical power is the outermost annular ring in the optical zone of the lens.

DETAILED DESCRIPTION OF THE DRAWINGS With reference to the drawings in detail, Figure 1 illustrates a preferred type of embodiment of a lens 10 designed in accordance with the teachings of the present invention, wherein a central area 12 is a circular disk containing the distance power. Rx spherical prescribed, basic and is surrounded by a plurality of ring rings 14, 16, 18 and 20 of spherical near power and alternating spherical distance power. In the first embodiment of Figure 1, an annular ring 22 of intermediate optical power, having an optical power intermediate to the optical powers at a distance and close, is added as a second outer annular ring. The annular ring 22 of intermediate optical power is encompassed by an annular ring 24 of remote optical power, outermost.

A preferred intermediate optical power is 50% of the difference between the remote and near optical powers, but could be chosen to be any optical power between the remote and near optical powers. A preferred position for the annular ring of intermediate optical power is in the outer region of the optical zone 26 of the lens, preferably the second annular ring 22, more exterior from the outer edge of the optical zone 26 of the lens. The entire area covered by the outer circumference of the outermost ring 24 defines the optical zone 26 of the lens 10, which includes the areas of 12, 14, 16, 18, 20, 22 and 24. The optical zone 26 is surrounded by a peripheral zone 28, which is a non-optical area of the lens, which is beveled at 30 to the outer circumference 32 of the lens. In more detail, in an exemplary designed embodiment, the central disk 12 and the annular rings 16, 20 and 24 have a radius of distance of 8.4 mm, while the annular rings 14 and 18 have a radius of closeness of 8.69443 mm, the annular ring 22 has an intermediate bend radius of 8.3803 mm and the radius of the peripheral e is 9.832 mm. The central toroidal disc 12 has a diameter of 2.15 mm, the annular ring 14 has a diameter of 3.30 mm, the annular ring 16 has a diameter of 3.60 mm, the annular ring 18 has a diameter of 4.30 mm, the annular ring 20 it has a diameter of 4.80 mm, annular ring 22 has a diameter of 5.35 mm, annular ring 24 has a diameter of 8.00 mm, annular lenticular area 28 has a diameter of 13.0 mm for the beginning of beveled area 28 and circumference The exterior of the lens has a diameter of 14.0 mm. Figure 2 is a plan view of a second embodiment of a multifocal lens design having intermediate optical power, in which the annular ring 44 of intermediate optical power is the outermost annular ring 44 in the optical region 46 of the lens. Similar to the first embodiment, a central area 32 is a circular disk containing the spherical distance power, basic prescribed Rx and is surrounded by a plurality of annular rings 34, 36, 38, 40 and 42, of spherical distance power and of near power, alternating spherical. The annular ring of intermediate optical power is the outermost annular ring 44 within the optical zone 46 of the lens. The combined areas of the spherical, central disk 32 and the surrounding annular rings 34 to 44 comprise the optical, active area 46 of the lens, which is surrounded by a peripheral (non-optic) area 48, which is bevelled in its outer circumference at 50 to an outer circumferential edge 52.

The area of the intermediate power portion preferably does not exceed 25% of the total area of the entire optical zone. It should be noted that the intermediate power is distinctive and different from the intermediate peripheral curve and is preferably a sphere. By varying the widths of the individual annular rings, a power profile can be created which generates different ratios of optical power at a distance to the near and intermediate optical powers with an increase in distance from the center of the lens. The size of a person's pupil is a function, which is dependent on the intensity of light and is an important parameter in the design of ophthalmic lenses, particularly contact lenses and intraocular lenses. Reliable data are obtained from people in four different age groups. Those with less than 20 years of age, those between 20 and 40 years of age, those between 40 and 60 years of age and those over 60 years of age. These measurements of the pupil are made in test individuals at three different luminance levels, 250, 50 and 2.5 candelas per square meter (cd / cm2). The level of 250 cd / m2 corresponds to extremely bright lighting, usually outdoors in bright sunlight. The level of 50 cd / m2 is a mixed level, which is found in both indoor and outdoor. Finally, at the 2.5 cd / m2 level it is most typically found outdoors at night, usually in a situation of uneven lighting such as night driving. The results of these studies are given in the following Table I, which also includes the average pupil diameter at three different illumination levels, the standard deviation in the diameter and the range associated with them.

TABLE I SIZE OF THE HORIZONTAL PUPIL LESS THAN 20 YEARS OF AGE Illumination Diameter of the Deviation (candelas / m2) Average Pupil (mm) Standard () 2. 5 6.5962 0.9450 50 4.3499 0.5504 250 3.4414 0.3159 FROM 20 TO 40 YEARS OF AGE Illumination Diameter of the Deviation (candelas / m2) Pupil Average (mm) Standard (1? 2. 5 6.4486 0.8259 50 4.4843 0.6342 250 3.5040 0.4217 FROM 40 TO 60 YEARS OF AGE Illumination Diameter of the Deviation (candelas / m2) Pupil Average (mm) Standard (1 S 2. 5 5.4481 0.9787 50 3.6512 0.5692 250 3.0368 0.4304 MORE THAN 60 YEARS OF AGE Illumination Diameter of the Deviation (candelas / m2) Pupil Average (mm) Standard (1?) 2.5 4.7724 0.6675 50 3.4501 0.5106 250 2.8260 0.3435 Taken in combination with these data, are the determinations that have • been made with respect to human activity in the real world, typically found under different levels of illumination. At very high lighting levels, such as that represented by 250 cd / m2, human activity is normally carried out outdoors in bright sunlight and requires distant vision tasks. At an illumination level of 50 cd / m2, activity usually occurs indoors and outdoors and typical human activity is represented by near and distant visual tasks. Finally, at low illumination levels represented by 2.5 cd / m2, the activity that is carried out is usually outdoors at night and usually involves distant vision tasks, such as driving a car. The corrective powers as a function of the distance from the center of the lens, must be a function of the pupil diameter measured specifically, the patient at varying levels of illumination, or can be easily determined from the above information based on the age of the patient . In addition, in vivo image quality measurement devices. Ocular can be used to optimize the quality of the ocular image in ring-shaped, concentric ring designs to produce even more improved designs. This is done using an in vivo image quality measurement device, such as an aberroscope or an MTF point extension measuring device., to measure and decrease the sum of the aberrations of the combination of the lens and the eye system. Obviously, many different embodiments of the present invention are possible, with alterations in the number of annular rings, the widths and arrangement of the annular rings and the optical powers assigned to each of the annular rings. Although various embodiments and variations of the present invention for multifocal lens designs with intermediate powers 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. The technique.

Claims (12)

NOVELTY OF THE INVENTION CLAIMS

1. A concentric, multi-focus annular ring lens characterized in that it comprises: a. the lens having a front surface and an opposite rear surface, wherein one of the front and rear surfaces defines a central area, comprising a circular disk having a spherical surface corresponding to a basic prescription Rx of optical distance power , spherical; b. a plurality of annular rings surrounding the central area and having alternately close optical, spherical and spherical remote optical powers; and c. at least one ring annular of optical power, intermediate, located in the outer region of the optical zone of the lens, which has an intermediate optical power, intermediate to the optical power at a distance and the near optical power, to provide visual acuity to intermediate distances.

2. The concentric annular ring lens of multiple focus according to claim 1, characterized in that the annular ring of intermediate optical power is the second annular ring of the outer edge of the optical zone of the lens.

3. The concentric annular ring lens of multiple focus according to claim 1, characterized in that the annular ring of intermediate optical power is the outermost annular ring which defines the outer circumference of the optical zone of the lens.

4. The concentric annular ring lens of multiple focus according to claim 1, characterized in that the annular ring of intermediate optical power is an annular ring in the outer radial portion of the optical zone of the lens.

5. The concentric annular ring lens, of multiple focus according to claim 1, characterized in that the annular ring of intermediate optical power, consists of the outer radial, complete portion of the optical zone of the lens.

6. The concentric annular ring lens of multiple focus according to claim 1, characterized in that the annular ring of intermediate optical power is an annular ring in the middle radial portion of the optical zone of the lens.

7. The concentric annular ring lens of multiple focus according to claim 6, characterized in that the annular ring of intermediate optical power is near the outer edge of the middle radial portion of the optical zone of the lens.

8. The concentric ring lens of multiple focus according to claim 1, characterized in that the lens comprises a contact lens to be used on the cornea of the eye.

9. The multi-focus, concentric annular ring lens according to claim 8, characterized in that the contact lens comprises a soft hydrogel contact lens.

10. The concentric annular ring lens, of multiple focus according to claim 1, characterized in that the lens comprises an intraocular lens.

11. The concentric annular ring lens of multiple focus according to claim 1, characterized in that the widths of the individual annular rings are different to generate a power profile, which varies to generate different optical power ratios at distance to optical power intermediate and close.

12. The multi-focus, concentric annular ring lens according to claim 1, characterized in that the central area and the plurality of annular rings are formed on the rear surface of the lens to minimize reflection and brightness problems. DISE OS TJB LENS MU T1 ÜCAL COK OPTICAL OIMLIAS JLNTM1MEDIAS SUMMARY OF THE INVENTION A multi-focus, concentric annular ring lens in which one of the front and rear surfaces of the lens defines a central area comprising a circular disk having a spherical surface, corresponding to a remote optical power, spherical basic prescription Rx. A plurality of annular rings surround the central area and have spherical, alternating, remote and near optical powers and at least one annular ring of intermediate optical power. The annular ring of intermediate optical power is located in the middle or outer region of the optical zone of the lens and its optical power is intermediate to the optical powers at distance and near, to provide visual acuity at intermediate distances. The annular ring of intermediate optical power can be placed on either side in the middle or outer region of the optical zone of the lens and can be the second annular ring from the outer edge of the optical zone of the lens, or it can be the ring annular plus exterior which defines the outer circumference of the optical zone of the lens. The lens can be a contact lens for use in the cornea of the eye, such as a soft hydrogel contact lens or it can be an intraocular lens.