MXPA00005132A - Optical lens - Google Patents

Abstract

A lens element adapted for mounting in eyewear, the lens element having a spherical surface with a radius of curvature less than about 35 mm, said lens element being adapted for positioning such that a center of curvature of the lens element is located at the centroid of rotation of the eye, wherein the lens element is sufficiently large to provide a field of view greater than 55°in the temporal direction from the forward line of sight.

Description

OPTICAL LENS DESCRIPTION OF THE INVENTION The present invention relates to ophthalmological lens elements,. improved ophthalmic products, including prescription lenses, glasses, sunglasses, safety glasses and frames for them. Most conventional prescription lenses have relatively flat base curves. Such lenses provide a limited field of vision due to peripheral distortion and / or physical size limitations. Their relatively flat shapes limit the magnitude of eye protection achieved by the lenses, particularly near the temples. A product has been developed for the use of curved tissue in an attempt to provide wider fields of vision and greater eye protection. The curved design also allows different styles, and sometimes surprising styles for the product for ophthalmological use. However, the product for curved ophthalmic use is typically not prescribed. These products also typically have flat base curves between 6 and 10 D. Bending (and sometimes deviation from the vertical) is achieved by rotating and / or moving the optical axis of the lens in the orientation used. See, for example, U.S. Patent No. 1,741,536 to Rayton; U.S. Patent No. 5,689,323 to Houston et al. This causes the line of sight of the user to deviate from the optical axis, and the optical performance is frequently significantly decreased. Typically, peripheral vision is poor. Already very early in the history of ophthalmological science, prescription lenses curved sharply had been described, although not as vehicles to provide greater field of vision or eye protection. A relationship between curvature and step power is shown in the so-called "Tscherning" ellipse. Described for the first time 100 years ago, it attempts to identify combinations of lens and power curvature and lens that have minimal aberration. The general shape of the Tscherning ellipse is shown in Figure 1. Figure 1 is given for typical values assumed for lens parameters such as refractive index, vertex distance, lens thickness, etc. The Tscherning ellipse retains its ellipsoid shape and inclined orientation for several assumed values of lens parameters, while the precise location of points on the ellipse may change. The ellipse of Figure 1 is established from the corrected von Rohr equation (according to Morgan) for distance vision (zero astigmatism) of focal point. The lower portion 10 of the ellipse is the so-called "Ostwalt section" which describes a selection of relatively flat front surfaces for lens powers typically used in conventional prescription ophthalmological lenses. The upper portion 12 of the curve, referred to as the "ollaston section," describes much more pronounced curved lenses which have not gained acceptance as lens forms, although there are historical instances of attempts to make such objects (e.g. Wollaston himself). See "The Principles of Ophtalmic Lenses" by M. Jalie, p. 464 (4th edition, London, 1994). Due to manufacturing difficulties, these first lenses were probably of small aperture and, consequently, perhaps, considered unacceptable for cosmetic reasons and because of their limited field of vision. Modern lenses have been made with sharply curved front spherical surfaces for the treatment of aphakia (absence of natural lenses of the eye as in the case of surgical removal of lenses). The general shape of these lenses is shown in Figure 2. See M. Jalie on page 151. Such lenses serve essentially as an ocular lens replacement and are characterized by a large thickness and high positive power (greater than + 5 D and typically + 12 D or greater). The opening A of these lenses is of small size, for example, 26 or 28 mm in diameter. Typically such aphakic lenses have a flat radial flange 14. Currently, the vast majority of conventional prescription lenses are relatively flat, simple-vision, Ostwalt section meniscus lenses, which are polished like window cloths within flat-frame spectacle frames. Applicants have studied the properties of sharply curved lenses and considered series of lenses having commonly prescribed positive or negative step powers. The applicants observed that such lenses could, in principle, provide a wide field of vision and eye protection. However, certain problems will interfere with the practical implementation of such wide-field lenses. Generally, there are manufacturing distortion problems, and problems producing a range of common positive and negative potency recipes with or without common available astigmatism correction or "easy" recipe. A more subtle problem is presented by the wide range of frontal surface powers which would be required to provide a range of common recipe powers. For the lens assumption of Figure 1, for example, the Wollaston section would be understood to show a variation in front surface power of from about 15 D to about 20 D for a range of line pitch power of product from + 5 D to + 8 D. This corresponds to a variation in the radius of curvature of the front surface from about 29 to about 39 mm, which represents a large variation in the size and overall shape for lenses large enough to provide a wide field of vision. Such lenses can not be shrouded like window cloths in a single frame size, in fact, each prescription in itself would dictate its own size and specialized frame style. While such unique styles have value, they are incompatible with providing ophthalmological mass marketing product with a consistent appearance. It is an object of the present invention to overcome, or at least alleviate, one or more of these difficulties and deficiencies of the prior art. Generally, the present invention relates to ophthalmological products and ophthalmic lens elements for this purpose. The ophthalmological lens elements may include, according to the context, carved or sharpened ophthalmological lenses, semi-carved lenses, lens blanks or molds therefor. Wafers are also included to form laminated lenses or lens blanks. Accordingly, in a first aspect of the present invention, there is provided a lens element adapted to mount to products for ophthalmological use, the lens element having a spherical surface with a radius of curvature of less than about 35 mm, said lens element to locate such that a center of curvature of the lens element is located in the centroid of rotation of the eye, in which the lens element is large enough to provide a field of view greater than 55 ° in the direction temporary from the forward line of sight. Preferably, the lens element is a single-vision lens element selected from a series of lens elements having pitch powers of from at least about +2 D to -2 D and about the same radius of curvature. It will be recognized that the increased field of vision allows the manufacture of products for ophthalmological use whose temporal border is not visible to the user (apparent absence of border). Other advantages include providing the designer of products for ophthalmological use with options hitherto unattainable in a lens having good peripheral vision properties in various recipes. These include the ability to use smaller contour lenses, interesting lens edges and eyeglasses curved three-dimensionally topologically and cosmetically, and edge thicknesses which are easily hidden from view, particularly in the temporal region. The present invention is exemplified with reference to Figure 3 which illustrates some geometric aspects of the concentric lens, sharply curved, of the present invention. Figure 3 shows a horizontal cross section of left and right eyes (20 and 22 respectively). Each eye is shown to have a centroid of rotation, 24 and 26. The centroid of rotation can be understood as a volume inside the eyeball, having a CD diameter of about 1-2 mm, around which the eye seems to rotate as the direction of contemplation varies. As shown in Figure 3, the left and right lenses 28 and 30 curved sharply are located around the eye. In the figure, the optical axis of each lens is co-linear with the line of sight of each eye and is represented by lines 32 and 34 for each eye. These lines also represent the z-axis of coordinate systems used later in the text to describe certain lens surfaces (the x-plane being normal and the plane of the Figure). The lenses 28 and 30 can be described in the same way as spherical or spherical base. In preferred embodiments, the front surface is spherical, having a fixed radius of less than about 35 mm for all recipe values in the series. In other embodiments, the lens is best described as having a spherical posterior side, such as containing a reference sphere or as lying within a defined spherical shell. In each case, the radius of the reference sphere or shell and the location of the lens as in use is such that the center of the reference sphere or shell lies near, or within, the centroid of rotation of the eye. The case in which the frontal surface is a sphere of radius R centered on the centroid of rotation of the left eye, is illustrated for the left eye in Figure 3. The selection of a spherical base of a radius die centered on, or near of, the centroid of rotation of the eye, places a restriction on the vertex distance d. , illustrated for the left eye of Figure 3 as the distance between the plane of the pupil 36 and the posterior surface 38 of the lens. The front surface radius and the back surface shape, in conjunction with other design parameters such as the lens thickness and the refractive index of the lens material, determine the optical properties of the lens as described in detail below. Applicants have found that the lens design of the present invention can be analyzed and described by a data arrangement of a type illustrated in Figure 4. The diagram is called a "Morris-Spratt" diagram according to two of the inventors. In the diagram, each spot is in the center of a graphical representation of ray trace, theoretical from a lens having properties of the network point in the center of the spot, the "y" axis on the right gives the surface power Front of the lens in diopters (normalized for refractive index of n = 1,530). The "x" axis at the bottom shows the power of the lens at its center.

This corresponds to the prescription of positive or negative power of the lens. For these Figures, it is assumed that each lens is made of polycarbonate (n = 1,586) and has a center thickness of 1.8 mm in negative power lenses, and a center thickness in positive lenses determined individually for each recipe so that the minimum total lens thickness is 1 mm at the periphery of a lens blank with a diameter of 58 mm. Each lens is located in relation to the eye such that the front surface is 33.1 mm from the center of rotation of the eye, which is concentric for lenses having a front surface power of 16.0 diopters. At each individual network point, a beam trace result appears for rotation angles of up to 40 degrees. The black area at each network point represents the region of each lens that has less than 0.125 diopters of RMS power error (root mean square) relative to the prescription and that allows up to 0.375 diopters of accommodation. The power error RMS (root mean square) is defined mathematically below. It is believed that this criterion is a good indicator of lens performance. The fully filled circles in Figure 4 represent lenses with less than 0.125 diopters of RMS power error (root mean square) over 40 degrees of eye rotation in either direction. For spots with rings around them, the power error RMS (root mean square) rises above 0.125 diopters for some intermediate eye rotation angles then falls below that threshold again for some small angular region. The elliptical contour of the locally larger spots corresponds approximately to the Tscherning ellipse generated for the special case of lens parameters selected by the applicants. Conventional common sense dictates that spherical lens front surfaces (lenses with spherical surfaces on the front and back) must follow the Tscherning ellipse to produce high quality lenses. However, the Morris-Spratt diagram illustrates that for an appropriate selection of lens parameters there is an almost horizontal region in this diagram where it is possible to produce excellent lenses. It is known that spherical flat lenses with high quality optics can be manufactured by extending over a wide range of front surface bends (a fact which is indicated by the vertical line of large spots near zero pitch power). Many such lenses are currently available in the market. The novel idea illustrated in the Morris-Spratt diagram is that it is also possible through an appropriate selection of lens parameters, to fabricate high-quality spherical lenses over a wide range of recipes using a single sharply curved front surface or surface or spherical reference shell. Note that regions of low power error RMS (root mean square) for lenses using a front surface power of 16 diopters (network points on line 40) have wide angular extent (full or nearly complete circles) over a range of at least -6 to +4 diopters. More than 95% of all recipes fall within this range. Therefore, it is possible to produce high-quality ophthalmological spherical lenses over a wide range of useful recipes using a single, appropriately selected, high-power front surface or base curve, and, as clarified in Figure 4, some small deviations from simple power or exact concentricity while providing good lens quality and a sufficiently consistent lens shape to use the same frame style Figure 5 illustrates a series of lenses of good optical quality of a preferred embodiment of In this embodiment, the front surface is selected to be around 16 D ± around M D. This range lies between horizontal lines 50 and 52. Particularly preferred embodiments provide lens series having a prescription in the range of -2 D to +2 D (area 54), -6 D to +4 D (areas 54 and 56), or -8 D to +5 D (areas 54, 56 and 58).

For comparison purposes, a portion of the Wollaston section of the Tscherning ellipse 60 for this special case has been superimposed on the diagram of Figure 6. The Figure shows that the front curve and pitch power ranges represented in the blocks horizontals are inconsistent with the Tschernig ellipse showing what would indicate a 5 D variation on the front surface for power from -8 D to +5 D and a much steeper curvature at the center of the step power range. In a preferred aspect of the present invention, a series of ophthalmological lens elements are provided, each lens element having a spherical front surface which is approximately concentric with the centroid of rotation of the eye in the position of use; approximately the same radius of curvature which is essentially a single value selected from the series in the range of 25 to 50 mm ± 1 mm; and in which the lens elements of the series have several common recipe step powers. More preferably, the lens elements have pitch powers of from about +4 D to -6 D. Advantageously, the series of lens elements are provided with the appropriate prescribed power and correctness. In the embodiment where the front surface is spherical, the rear surface is configured to provide adequate pitch power and correctness. In a preferred embodiment, a series of lens elements would include power to pass through the above ranges in increments of D. Deposit lens elements would be provided for each power with each of the various common astigmatism prescriptions, for example , OD up to -2 D in increments of Vi D. It will be understood that by the spherical symmetry of the lens element, the angle of the. Correct correction can be selected by appropriate rotation of the lens element during edge forming and carving. The conventional astigmatism correction is based on toroid surfaces frequently described in terms of the main meridian, that is, orthogonal meridian centered on the optical axis of the lens, representing the site of maximum and minimum curvatures. Barrel toroids and thread toroids have been used to provide easy corrections. As described below, applicants have developed novel astigmatism correction surfaces for sharply curved lenses, whose surfaces can be described as lying between a barrel toroid and a screw toroid each having the same principal meridian and the same power as the long of the main meridian. Two such surfaces are the "all-circular meridian" surface and the "averaged toroid" surface described in detail below.

Accordingly, in a preferred embodiment, the back surface lies between a barrel toroid and a screw toroid, both having the same principal meridian and the same power along said main meridian. More preferably, the surface astigmatism of said back surface at any point outside the main meridian is less than the larger surface astigmatism of the barrel toroid or the screw toroid at the same point. Alternatively, the back surface is defined such that the surface height Z of the lens element from a fronto-parallel plane at any point on the back surface is a linear combination of the height of a barrel toroid, ZB and the height of the thread toroid, Z being limited by the values of ZB and Zt. In another preferred aspect, the cross section of the rear surface of the lens element along any meridian is circular. Preferably, the curvature of each circular meridian is equal to the instantaneous curvature of a corresponding meridian in the center of a conventional toroid given by the recipe. The posterior surface astigmatism correction is given by the surface height function z (r,?) Where *** * (r,?) * R (?) - (? J * and where R (0) R (90) (?) R (0) sep2? + R (90) cos2? is the radius of curvature along the meridian ,2 . "2 and the values R (0) and R (90) are the radii d curvature along the main meridian, - alternatively, the posterior surface, together with the frontal surface provide a non-zero power and the posterior surface is defined by the equation: * -fc-SOA.j-S0.2_cwjxk- The shape of the lenses of the present invention will now be described. The term "pronounced curvature" is used in this context to describe the global shape of the reference sphere or shell. In particular examples the curvature can be quantified as an average radius curvature of a surface or spherical shell lying inside of the outside of the lens or containing a surface of the lens. Accordingly, in another aspect of the present invention, an ophthalmological lens element is provided having a surface which lies within a spherical shell defined by two concentric spheres having spokes whose lengths differ by no more than 2 mm, the smallest being of the spokes no more than 50 mm long and in which at least two points 0 and Q on the edge of the surface subtend an angle OPQ greater than 80 ° with respect to a center of the shell P. Preferably, the small of the spokes is between 25 and 35 mm and the difference in length of the spokes is around 0.1 mm or less. More preferably, the surface has a radius of about 33 mm ± 2 mm. The lenses of the present invention are also generally characterized by their large angular field of view, often expressed as an angle between the optical axis and the more temporal and nasal ends of the edges. According to preferred embodiments of the present invention, the lens subtends an angle centered at the center of a frontal spherical surface, the angle being greater than 80 ° and in preferred embodiments greater than 100 °. It will be understood that such angles are indications of the field of view of the lens assuming, of course, that the lens is optically usable in these peripheral regions. The unique topological shape of the lenses of the present invention can also be characterized by the sagittal depth or depth of "hollow" which are generally a measure of the three-dimensionality of the lens at the lens edge. These depths refer to the distance between the fronto-parallel plane of the lens and the more temporal edge point, as described below. According to preferred embodiments of the present invention, lenses with an average radius of not more than 50 mm centered on the centroid of rotation of the eye and having a depth of cavity of at least 8 mm are provided. In a particularly preferred embodiment the radius of the front surface is about 33 mm ± about 1 mm and the depth d is at least 10 mm. In another aspect of the present invention, there is provided an ophthalmological lens element including a spherical front surface which is approximately concentric with the center of rotation of the eye and having a base curve of 16 ± approximately V? D and exhibiting relatively low error d RMS power (root mean square) about 40 degrees of eye rotation. Preferably, the lens element is such that foveal vision torque the power error RMS (root mean square) is less than 3/8 D for eye rotation angles less than 30 °. The present invention also includes methods for providing prescription ophthalmic products. Accordingly, in yet another aspect of the present invention, it provides a method of providing prescription ophthalmic products including the steps of providing a lens element having a front surface which lies within a spherical shell of a thickness no greater than about 2 mm and a radius of no more than about 35 mm; and a rear surface configured such that the lens element has a prescribed step power and a prescribed astigmatism correction; and locating the lens element on the user so that the center of the spherical shell lies approximately at the center of rotation of the eye. Preferably, the lens element is located by carving the lens element within a frame having a standard aperture corresponding to a radius of a spherical shell common to a plurality of lens elements having different pitch power, including the prescribed pitch power. More preferably, the lens element is provided with a rear surface which has a circular cross section along any meridian through its origin, and whose curvatures along these meridians are identical to the central curvatures of the toric. equivalent conventional.

The present invention also includes specially designed spectacle frames. In a preferred embodiment, a spectacle frame suitable for use with a series of ophthalmological lenses is provided, each having a spherical surface of a single radius between 25 and 35 mm, and a second surface selected to provide in conjunction with the surface Spherical diverse common recipes. The frame can be adapted to support left and right lenses on the user so that the centers of the spherical surfaces are located at or near the centroids of rotation of the left and right eyes, respectively. The goggle frame may include temples and edge portions to engage the left and right lenses. The edge portion that engages each lens can be formed in the form of a closed curve lying on a reference sphere having a radius approximately equal to the radius of said spherical surface. In such spectacle frames, the most nasal point and the most temporary point of the closed curve can subtend an arc greater than 90 ° with a vertex at the center of the spherical surface. Eyeglass frames may include a left leg, a right leg and a nose bridge. In a preferred embodiment, the nose bridge is of adjustable length to allow adjustment of the lens spacing to locate the centers of the spherical surfaces at the centroids of the eyes. In other embodiments, hingeless goggle glasses are provided to support the lugs, the hinges being adapted for direct attachment to the reference spherical surface at the temporal edges of the respective lens. The foregoing is intended only as a summary of the invention, being within the scope of the invention determined by the literal language of the claim and equivalents thereof. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a drawing of a Tscherning ellipse; Figure 2 is a cross-sectional view of a positive high-power "rotoid" lens of the prior art; Figure 3 is a cross-sectional top view of a pair of human eyes, and lenses configured in accordance with a preferred embodiment of the present invention; Figure 4 is a Morris-Spratt diagram illustrating properties of series of lens elements made in accordance with teachings of the present invention; Figure 5 is a diagram of ranges of front curves and step power selected in accordance with the present invention, with a portion of the Tscherning ellipse for this special case superimposed thereon; Figures 6 (a), (b) and (c), 7, 8 and 9 are schematic diagrams illustrating various aspects of the geometries of the lens elements of embodiments of the present invention; Figure 10 presents a comparison of fields of vision for an example of a conventional base 6 lens and a lens and lens element of the present invention; Figures 11 (a) and (b) illustrate surface astigmatism of a conventional toric and barrel imposed on a sharply curved spherical lens having a main meridian, shown in Figure 11 (c); Figures 12 (a) - (d) are power graphics of tangential and sagittal surfaces as a function of a polar angle for the toric and barrel toric of Figure 11; Figures 13 and 14 are graphs of tangential and sagittal surface power as a function of the polar angle for the all-circular meridian and the averaged toric surfaces of the present invention; Figures 15 and 16 are graphical contour representations of surface astigmatism for lens element surfaces employing the teachings of the present invention; Figures 17 (a), (b) and (c) illustrate a network object of images thereof; Figure 18 is a cross-sectional side view of a mold that can be used to make lens elements of embodiments of the present invention; Figure 19 contains graphical representations of RMS power error (root mean square) and distortion and a ray tracing network calculated for three conventional low base lens and three sharply curved lens elements according to the present invention; Figure 20 contains graphical representations of RMS power error (root mean square) and distortion and a ray tracing network calculated for a sharply curved lens with a conventional toric back and for a back part of a full circular meridian; Figures 21 and 22 are graphical contour representations comparing a conventional 6 D base progressive lens with a 16 D base progressive lens according to the present invention; Figures 23, 24, 25 and 25 (a) illustrate various aspects of the appearance, sharpening and polishing of lens elements of the present invention and spectacle frames for use with them. Scheme I Basic lens geometry. II Correction of astigmatism. III Reduction of effects of increase and distortion. IV Manufacture of lens. V Calculated performance of lens design examples. VI Lenses polished and frames of glasses. I Basic Lens Geometry First, the basic geometry of lenses made in accordance with the present invention will be discussed. Figures 6 (a), 6 (b) and 6 (c) respectively illustrate front, side and top views of a sharp lens 100 according to the present invention. The origin 102, in Figure 6 (a), at the location of the optical center of the lens and the design location of the center of the pupil when in use. The contour 104 of the sharp lens is indicated from a front view perspective in Figure 6 (a). In Figure 6 (b) the temporal border 106 and the nasal rim 108 of the lens are shown. In Figure 6 (c) the upper edge 110 and the lower edge 112 of the lens are shown. In the lens embodiment of Figure 6, the front surface of the lens is a pronounced spherical curve, the extension to the right of which is indicated by line 114. The pronounced spherical curvature of embodiments of the present invention may be designed on the lens in a variety of ways. In the preferred embodiment, discussed above, the front surface of the lens elements is a single radius sphere centered at, or near, the centroid of rotation of the eye. Alternatively, the back surface of the series of lens elements can be a sharply spherical surface centered on or close to the centroid of rotation. In these embodiments, the other surface is of variable curvature, the curvature being selected to provide at least the appropriate passing power for the user. For example, if a spherical surface of 16 D is selected for the lens element series, a back surface with a curvature of 20 D over its major meridian and 18 D over its minor meridian can be used to provide a step power of 4D with a -2 D cyl. Alternatively, if the constant radius surface of the lens element is placed on the back surface, then the corresponding surface selected for the particular recipe can be placed on the front surface. In other alternatives, the lens element or a surface is constrained to lie within a spherical shell. This geometry is illustrated in Figure 7. Two concentric spheres 154 and 156 are defined by a center at Point P and two radii t1 and r2 where r2 > rx. Together the spheres define a shell S. A lens 158 is shown having a nasal end edge point Q and a temporary end edge point O. A front surface 160 of the lens lies within the shell S. A front surface of the lens Optical lens element according to the present invention may be spherical, toric or a rotationally symmetric spherical surface. To improve the vision even more, the front and / or back surface of the optical lens element according to the present invention can deviate from a spherical shape to provide improved optical performance and / or cosmetic appearance. The front and / or back surface, as described above, can be "established by solving the optimization problem to minimize a selected merit function by representing a measure of optical aberrations seen by the lens user. or in addition, to improve the cosmetic appearance of the lens element Alternatively, the surface inside the shell may be a progressive mui-focal lens as described in more detail below In a preferred embodiment, the lengths of the radii Rx and r2, they differ by no more than 2 mm, and in a more preferred embodiment one of the spokes is about 33 mm and the difference in the lengths of rx and r2 is about 0.1 mm or less. OPQ angle greater than 75 °, preferably greater than 90 ° and more preferably greater than 100 ° This angle is a measure of the wide field of view provided by the lens. The lens may be defined to lie entirely within a shell defined in a manner similar to the shell S of Figure 7, where the difference in length of r1 and r2 is less than 6 mm. Additionally and alternatively, the lens may be defined as containing a portion of a pronounced curved sphere such as the portion OQ of the sphere having radius r1 in Figure 7. The reference sphere may be a sphere lying intermediate between the front surfaces and Rear of the lens element. In embodiments of the present invention this pronouncedly curved sphere may define butt surfaces of two other lens wafers made in accordance with U.S. Patent No. 5,187,505 which is incorporated herein by reference. In such a case, the ophthalmic lens lens blank is formed as a back and front wafer laminate. Since the top surfaces of the wafers are spherical, it will be understood that the wafers can be rotated to achieve the desired orientation of a correct correction applied to one of the surfaces. This is particularly useful in providing progressive lenses. Other aspects of the novel geometry of the lens elements of the present invention are illustrated in Figure 8. A lens 170 is shown, with a pronounced spherical curve, approximately concentric with the centroid 172 of rotation of the eye. The fronto-parallel plane P is tangent to a spherical front surface 174 of the lens. The optical axis 176 of the lens is normal to the plane P and passes through the centroid of rotation of the eye. A back surface is identified by the number 178. The lens extends in a temporary direction to a temporary edge 180. The novel geometry of the lens is defined in part by a depth of hollow ZH, which is the perpendicular distance between the surface rear 178 of the lens on the optical axis and the edge 180. A related dimension ZF, is the distance between the fronto-parallel plane P and the edge 180. It is instructive to consider the peripheral optical properties of the lenses of the present invention, such as distortion. In such cases, reference can be made, as shown in Figure 9, to lens properties lying in or out of a semi-angle cone f centered on an optical axis 0. In Figure 9,? It is shown as an angle of 30 °. In a preferred embodiment of the present invention, the lens element of the series has a surface astigmatism of less than 0.125 D through a cone defined by an angle? of at least 25 °. A lens element of the present invention may be such that for foveal vision the RMS Power Error (root mean square) (defined below) is less than 3/8 d for eye rotation angles of less than 30 °. Likewise, the lens element can be such that for foveal vision the RMS Power Error (root mean square) is less than M D for eye rotation angles greater than 30 ° and less than 40 °. Finally, the lens element may be such that for foveal vision the RMS Power Error (root mean square) is less than 3A D for eye rotation angles greater than 40 ° less than 50 °. In preferred embodiments, the lens element can be configured such that for peripheral vision where the eye is rotated and fixed at an angle of 30 ° temporarily the RMS Power Error (root mean square) is less than 3/8 D for angles ± 5 ° from the set position; the RMS Power Error (root mean square) is less than 0.65 D for angles ± 10 ° from the set position; and the RMS Power Error (root mean square) is less than 1.0 D for angles ± 30 ° from the set position. Certain features of the present invention and a comparison with a conventional lens are illustrated in Figure 10. Figure 10 (a) illustrates a selected plan view contour for a conventional lens and a sharply curved spherical lens of the present invention. A conventional base lens 200 D is shown in Figure 10 (b) and a base lens 202 D in accordance with the present invention in Figure 10 (c), both having the same flat contour as in Figure 10. (to) . The apparent field of vision is measured between edge rays centered on the center C of the pupil in the pupillary plane. The conventional base 6 lens has an apparent field of view of about 105 ° while the lens 202 has an apparent field of view of about 130 °. If a larger lens blank and a larger flat contour is used, a base lens 16 D of the approximate size of FIG. 10 (d) can be produced. Such a lens can extend horizontally from the nasal margins 206 to the temporal margins 208 of the orbital region producing an apparent field of view of about 170 °. Such a lens would not have a temporal edge that could be seen by the user when looking forward. Also, the lens temporal edge thickness 210 would not be easily observed by another person because it curves in a posterior direction, thus improving the cosmetic appearance of the lens. Finally, the posterior surface 212 of the lens will clear the normal length lashes for a wide range of recipes. II Correction of Astigmatism The sharply curved spherical lenses according to the present invention present particular problems when a correct correction is part of the user's recipe. Common toric posterior surfaces may not provide acceptable performance. In particular, O-rings do not work well on the periphery of sharply curved lenses. The ideal posterior surface for a Rx cyl (neglecting things like lightning obliquity) would have a constant surface astigmatism appropriate for the recipe. There is no such surface. The toric surfaces are an approximately manufacturable to this ideal. There are two standard types of toric surfaces, sometimes referred to as toric and toric ores. Each one is made by sweeping a circular arc around a fixed axis. If the radius of the circle is smaller than its maximum distance the fixed axis is then a toric thread, otherwise it is a barrel toric. Both types of toric have circular cross sections along the two main meridians, so (and symmetry) the tangential power is correct everywhere along these meridians, and each type of toric has a "preferred" meridian. "where the sagittal power is correct." For the toric toric it is the lowest tangential power meridian, for the barrel toric it is the highest tangential power meridian.Short tangential and zero sagittal means that the surface astigmatism is identically zero Along the preferred meridian, examples of conventional torics in sharply curved lenses are shown in Figures 11 (a) and 11 (b) Both examples have tangential power of 18 diopters (@ n = 1,530) over the equatorial meridian of 180 degrees and 20 diopters at 90 degrees, for a nominal 2. The graphic representations are 45 mm in diameter and have r level curves of 0.1 diopters. The southern circular major curvatures Cl and C2 intersect at a central point at the P pole at an angle of 90 °. It will be understood that other "non-main" meridians can be defined radially from the central point. The preferred axis is obvious from the graphical representations of Figure 11. The tangential and sagittal surface power for angles of 0 to 90 degrees around the radii 0, 10 and 20 mm from the center are threaded in Figures 12 (a) - (d). From the figures it can be noted that both the toric and barrel toric have the correct tangential power at 0 and 90 degrees for all radii. The thread toric has the correct sagittal power at 0 degrees, but an error at 90 degrees that increases with the radius. The barrel toric has the correct sagittal power at 90 degrees and errors that increase with the radius at 0 degrees. There is something obviously asymmetric about both of these torics; each of them has a preferred meridian. However, there are functions that preserve the correct tangential powers along major meridians, but treat the sagittal powers more symmetrically. One way to build a function with the desired tangential behavior is to force the cross section along any meridian to be circular. The function would have the form z (r,?) R (?) - VR (?) 2-t2 'Where R (?) Is the radius of curvature along the meridian?, And r = ^ x2 + y2. The values of R (0) and R (90) are set by the desired tangential powers and the powers at intermediate angles are determined by interpolating between these end values. One way to interpolate comes from recognizing that the shape of the power profiles above are almost sinusoidal. Then a good first approximation for the R (?) Would be P (?) = P (0) + P. (90) - P (0)) (lcos2?) / 2, and R (?) = (Nl) / P (?) Where P is the tangential power and n is the refractive index to convert power into curvature. To add more control over sagittal behavior, more Fourier terms could be added to the interpretation. For more control over the tangential behavior one could make the polynomial power in r. For a simple surface, additional degrees of freedom would not be required. The graphical representations of Figure 13 show the tangential and sagittal powers as a function of the angle as shown above for the torics. Note that tangential errors at intermediate angles are less than the thread and greater than barrel torics. Note also that the sagittal potential is corrected at 0 ° and 90 ° for r = 0, but starts to get lost on both meridians, more or less symmetrically, as the radius increases. For a surface that is not axially symmetric there is a weak contribution of angular behavior on the tangential curvature. This is because the normal vector is in the same plane as the circular cross section. Another way to produce an "undifferentiated" cylindrical correction surface is to average conventional toroidal and barrel toric couplings together. Doing this gives results that are similar to those for the surface constructed from circular meridians. The angular graphical representations for the averaged torics are shown in Figure 14 in which Z = aBZB + (1 - aB) ZD where Z is the surface height of the lens, ZB is the surface height of a conventional barrel toric; ZD is the surface height of a conventional thread toric; and aB is a weighting factor such that 1 > aB > 0. Figure 14 shows the specific case for aB = 0.5. It is difficult to say from the graphical representations of Figure 14, but there are significant differences in the angular behavior of the tangential and sagittal powers for these circular meridians and averaged toric surfaces. The graphical contour representations of Figure 15 compare the surface astigmatism of the averaged toric and the circular meridian functions. The graphic representations have the same level curves of 0.1 diopters and 45 mm in diameter as before. Astigmatism behaves more simply for the circular meridian surface than for the averaged toric. To show the effect of adding Fourier terms to the angular interpolation, an additional coefficient can be adjusted to "round" the level curves that look elliptical. The results are shown in Figure 16. Note that the meridians still all have circular cross sections, only the angular interpolation has been slightly changed. The averaged circular and toric meridian surfaces have additional properties to notice. The surface astigmatism of the surface at any point outside the main meridian is' less than the largest of the surface astigmatism of the barrel toric or the toric of the same point. In addition, the averaged toric or circular meridian surfaces lie between (have an intermediate Z value) between the barrel toric and the toric toric of the same recipe. While the preceding torics are preferred for use as backsheets for lenses of preferred embodiments of the present invention, it is possible to use conventional or toric generalized torics to provide the lens.

Alternatively, the surface correction for lens elements of the present invention can be provided by producing a back surface according to the following mathematical description of a symmetric polynomial: k-Q, 2 ~ j.0.2-. A number of measurements of optical aberrations of a lens are defined as follows (EMP) = [(ff11 - ^ 22) 2 + 4fff2] l Error of RMS potential error (RMS blur) (emp) + - (error where e is the focal error matrix and you can write where e12 = e21 by the choice of the orthonormal base set. Where these terms are calculated by specifically considering the optical properties of the lens, the terms Optical Medium Power Error, Optical Cil Error and RMS Optical Power Error are applied. The merit function (s) can (s) be selected from the following functions depending on the specific application of the optimized lens: I M1 < = ^ (rms blur) 2 M2 =? [(? Mp) 2 + (error c -ni1) 2 3 =? (^ (Emp) 2 + (error cyl) 2 horizontal Vírtics!, Or - ^ bli¡c, u-o,, 4 =? ("); + S (**) \ +? (? Mp) M, -? (emp) 2 + - (error c) 2 16 'where the summations are about a rotation number? of eye of sample. In the case of M4, are there different defocusing measures used depending on whether the sample point? represents a horizontal, vertical or oblique rotation from the right forward position. This mode can provide some generalization of the "tangential error" design strategy 'minimum' spherical.

Modes M3 and M5 represent, respectively, strategies of "minimal astigmatic error" and "minimum average power error". In another embodiment, a term may be included in the merit function representing the lens cosmetics. For example, instead of using M alone, a modified merit function can be defined by: M * = M +? A? 2 V • > pr where? e denotes the number of rotations? of sample eye considered in M, r is a specified lens radius, and V is the lens volume outside the radius r. The factor ? it is seen as being a weighting of the average lens thickness. III Reduction of Magnification and Distortion Glasses either reduce or increase objects seen through them. This occurs because the main planes of conventional spectacle lenses are located near the lens and do not coincide with the pupil of the eye. In general, positive power lenses make things look bigger, and negative power lenses make things look smaller. The magnification also changes the perceived direction of objects in the peripheral field, and causes the apparent field of view to differ from the true field of view through the lens.

In addition to magnification, spectacle lenses also distort the shape of the objects seen through them. For an eye looking straight ahead, the negative lens creates the so-called "barrel distortion" in which the rectangular objects appear compressed in the periphery so that the squares look like barrels. Conversely, lenses with positive power create "pad distortion" which stretches out the corners of the squares. The two effects add up to degrade the perception of the size, shapes and position of the object. Textbooks on ophthalmic ophthalmology teach that it is not practical to correct distortion in glasses, and silence about the desirability of reducing the effects of magnification. But one of the advantages of contact lenses exaggeratedly praised is that the close fit of the lens to the eye reduces the magnification and distortion effects, allowing a more natural correction of vision. It would seem desirable to reduce the magnification and distortion of the spectacle lenses is possible. Relative Gap Increase For a distant object, the magnifying effect is defined by the following equation: Increase in relative glasses where d (dv in Figure 3) is the distance from the posterior surface of the lens to the pupil of the eye, Fv is the posterior vertex power in diopters, t is the thickness in meters, n is the refractive index , and Fx is the frontal surface power in diopters. The part of the equation that is inside the first set of parentheses is often called "Power Factor" because it shows how much increase is due to the lens power. If d could be equal to zero, then the power factor would be equal to l. In other words, a lens in contact with the eye would have very little increase due to its power, and this is what happens with contact lenses. Eyeglasses are located away from the eye to avoid contact with the eye, eyelids, or eyelashes, so this term is greater than 1 for positive lenses and less than 1 for negative lenses. In other words, positive-power glasses tend to increase and negative lenses tend to shrink. According to the context, the term "augmentation effects" is used both to describe increase and decrease. The part of the equation inside the second set of parentheses is usually called "Form Factor" because it shows how the increase varies with the thickness and curvature of the lens. If the lenses did not have thickness, then t would be equal to zero and this term would be equal to 1.

The ideal "thin lens" of third-grade optics would have no magnifying effect due to shape. Contact lenses come close to this condition because they can be made extremely thin. Glasses have a significant thickness to avoid breakage and always have positive frontal surface curvatures, so this term is greater than 1. In other words, all positive meniscus glasses lenses tend to increase due to their shape. To eliminate the effects of increase, the equation must be adjusted equal to 1, then the product of the power and shape factors must be equal to 1. As both, the power factor and the form factor in positive lenses are each one greater than one, your product can not be the same. to 1, then no positive lens in a positive meniscus can ever be free of magnification. On the other hand, negative lenses have power factor less than 1 and a form factor greater than 1, so it is possible to force these factors to cancel. To do this, we must solve this equation to increase unity. After doing so, we obtain the following relation: ndPv t = - (D ^ v) This equation specifies the lens thickness that eliminates spectacle magnification effects. It works by placing the second main plane of the lens in the pupil of the eye. Achieving this in a practical thickness requires two things: a negative lens power and very pronounced curves. Distortion According to third-order theory, distortion can only be eliminated within lenses so pronouncedly curved that it is impractical. "The Principles of Ophtalmic Lenses" by M. Jalie, 4th edition, page "461. The theory of third order fact requires posterior surface curves of more than 35 Diopters, which would be concentric around the entrance pupil of the eye; such surfaces would really be impractical.A truly concentric lens design that has both concentric surfaces around the eye's entrance pupil would have no distortion at all because the symmetry of the lens would ensure that all beam beams from oblique objects found the same slopes of When concentrically around the entrance pupil requires extremely sharp curves, we have found that slightly flatter curves also drastically reduce distortion when combined with lenses that have the principal planes near the pupil of the central pupil. This occurs with lenses designed to reduce increase in negative power lenses, and results in lenses that are closer to concentric around the eye's centroid of rotation. In fact, it is highly desirable to make the lens concentric around the center of rotation of the eye because this will improve the symmetry of the lens for the eye as it rotates to see objectives in the peripheral field, resulting in improved resolution. If we strictly require that a lens surface be concentric around the centroid of rotation of the eye, we can establish a thickness that virtually eliminates distortion. In this case, a special form of the equation is required for the lens thickness. For example, in a lens that has its concentric frontal surface around the centroid of rotation of the oo, we can solve for t in terms of the radius of the frontal surface, the distance adjustment, the refractive index, the posterior vertex power and the distance of the entrance pupil from the center of rotation of the eye. In this case where is a lens shape factor, rx = front surface radius; df = distance from the front lens surface to the plane of the input pupil; and KT is the distance from the center of rotation of the eye to the entrance pupil of the eye as shown in Figure 3. Figures 17 (a) - (c) show the advantage of this type of design. Figure 17 (a) is a representation of a large network to be viewed from a great distance, such that the network extends 45 degrees to the left and to the right - of the observer. "Figure 17 (b) is a calculated image of what a person using a conventional lens of -5.00 D would see, the network seems smaller and distorted in shape Figure 17 (c) shows the calculated image seen by a person using a lens designed to eliminate the distortion according to the present invention The image looks almost identical to the original object IV Lens Fabrication The ophthalmological lens elements according to the present invention can be formulated from any suitable material.A polymeric material can be used.The polymeric material it can be of any suitable type The polymeric material can include a thermoplastic material such as polycarbonate or thermoset material such as glycol diallyl carbonate type, for example, can be e use CR-39 (PPG Industries).

The polymeric article can also be formed of crosslinkable polymer melt compositions, for example, as described in US Patent No. 4,912,155 or US Patent Application No. 07 / 781,392, all of the disclosures of which are incorporated in the present for reference. The polymeric material can include a dye, including for example, a photochromic dye, which can be added to the monomer formula used to produce the polymeric material. The optical lens element according to the present invention may further include standard additional coatings to the front or back surface, including electrochromic coatings. The front lens surface may include an anti-reflection coating (AR), for example, of the type described in the Patent North American No. 5,704,692, the entire disclosure of which is incorporated herein by reference. To make sunglasses or to provide a desired cosmetic effect, a partially reflective coating can be applied to the lens. The front surface of the lens may include, alternatively or additionally, an abrasion resistant coating, for example of the type described in US Patent No. 4,954,591, the entire disclosure of which is incorporated herein by reference.

The front and rear surfaces may further include one or more surface treatments conventionally used in casting compositions such as inhibitors, dyes including thermochromatic and photochromatic dyes, for example, as described above, polarizing agents, UV stabilizers and materials capable of modify the refractive index. Figure 18 illustrates a mold suitable for making a lens element according to the teachings of the present invention. The mold includes a front mold portion 300, a back mold portion 302 and a closure flange portion 304. The lens element can be formed in the cavity 306 between the mold halves by injecting liquid lens material through the mold. orifice 308. Air escapes through orifice 310. When the lens element is hard, the mold halves are separated. It will be noted that the lens element when leaving the mold will have a radial flange 312, which can be removed in a further processing. V Calculated Performance of Lens Design Examples Example 1 Table 1 shows a comparison of the calculated performance of a polycarbonate lens according to the present invention and a conventional low base curve lens.

E xemployment 2 Figure 19 illustrates a calculated comparison between a series of sharply curved spherical lens elements of -6 D, -3 D and +3 D power (Figures 19 (a), (c) and (e) respectively ) with corresponding Sola Perma-Poly® low base curve reservoir lenses (Figures 19 (b), (d) and (f), respectively). The sharply curved spherical lens elements have essentially identical spherical face surfaces of 16 D as shown in the lens cross sections 400. Generally the sharply curved spherical lens elements provide superior peripheral distortion. The lenses of Figures 19 (a) and 19 (C) also exhibit reduced RMS power error in the negative recipes. Example 3 Figure 20 illustrates a calculated comparison between two sharply curved spherical lens elements with a pitch power of -3 D of front surface of 16 D and a cyl correction of -2 of rear surface. The lens of Figure 20 (a) has a conventional thread back; of the lens of Figure 20 (b) has a circular meridian rear part of the type described above. The latter exhibits superior RMS power error and slightly improved distortion. Example 4 The last set of examples (Figures 21 and 22) is a calculated comparison between a progressive conventional base curve lens and a progressive lens according to the present invention. Figure 21 compares remote viewing properties of a conventionally curved Sola XL progressive lens, with a lens in which a similar progressive shape is placed on a lens element with a steeply curved base curve (16 D). - Figure 22 compares near vision properties of the Sola XL progressive lens with the sharply curved lens of Figure 21. Generally speaking, progressive lenses made in accordance with the present invention are characterized by a sphere or spherical shell of reference sharply curved approximately concentric with the centroid of rotation of the user in the position of use. Such lenses have a superior vision zone for distance vision; a lower vision zone, having greater power than the upper vision zone for near vision and an intermediate zone connecting the upper and lower zones, with variable power between the upper and lower zones, including a relatively low surface astigmatism corridor. In one embodiment, the sharply curved reference sphere corresponds to the front surface of the central part of the upper vision zone. In another embodiment, the progressive surface is on the front surface of the lens and lies within a sharply curved spherical shell of less thickness than about 2 mm. In both embodiments the radius of curvature of the reference shell may be less than 50 mm, preferably between about 30 and 35 mm, most preferably about 33 mm ± about 2 mm. Front surface designs suitable for progressive lenses are illustrated for example in the patent application of the Applicant Series No. 081782493 filed July 10, 1997, now US Patent No. 5861935 A. VI Lenses polished and goggle frames The spectacle frames for use in the present invention are adapted to hold lenses of the present invention in the approximate position shown in Figure 3. The spectacle frame may be without edge, with partial edge or with full edge In preferred embodiments, the lenses when they are mounted on the spectacle frame, they essentially do not exhibit an angle of decline or inclination The spectacle frame may include an adjustable mechanism for altering the positions of the optical axis of the lens so that it corresponds to the axis of vision in front of the user.

Figure 23 is a perspective view of product for ophthalmological use 400 including lenses 402 and 404 and spectacle frames of the present invention. The lens shape creates a cosmetically interesting object. The spectacle frame of Figure 23 is shown with a portion of edge 406 and lugs 408 and 410. The edge of the goggle frame surrounding each lens is adapted to correspond to a closed curve lying on, or near, the reference sphere curved sharply from the lens. For the consistency of this curvature through a range of recipes, a single frame or frame design can be calculated to any recipe in the range. Figure 24 is a side elevational view of the product for ophthalmological use of Figure 23 on the face of the user. The figure illustrates another aspect of the visual appearance of the product for ophthalmological use due to the pronounced curvature of the lens and the complex three-dimensional shape of the lens edge. L-r figure also illustrates that a lens of relatively small size provides a wide field of vision and good eye protection. Figure 25 is a front drawn view of the product embodiment for ophthalmological use 412 according to the present invention illustrating certain mechanical aspects of the invention. The spectacle frames of the embodiment of Figure 25 include a nose bridge 414 and hinged legs 416 and 418. Together, these components comprise a three-piece edgeless spectacle frame. The pins 416 and 418 include hinges 420 and 422, mounting tabs 424 and 426. In a preferred embodiment, the tabs 424 and 426 are surfaces mounted on the spherical front surfaces of the lenses. It will be understood that these mounting surfaces will have a consistent position and an angular relationship with respect to the frame, regardless of the prescribed pitch power and the correct lens correction. In a similar manner, the appendices 428 and 430 of the nose bridge 414 may be surfaces mounted on the respective front surface edges of the lens. The nose bridge 414 is shown in cross section in Figure 25 (a). Advantageously, the nose bridge can be made in an adjustable length to compensate for different pupil distances (PD in Figure 3) commonly found in different users. This adjustable feature allows the optical axis of the lenses to be adjusted with the viewing axes of both user's eyes. A suitable mechanical structure for producing this adjustable feature is shown in Fig. 25 (a), it being understood that other combinations of movable or flexible structures could be adapted for the purpose. In the embodiment of Figure 25 (a), each of the appendages 428 and 430 is carried by members 432 and 434, respectively, which are inserted into opposite ends of a tube 436.

Adjusting screws 438 and 440 hold members 432 and 434 in position. The adjustment screws can be loosened to allow the adjustment of the length of the nasal bridge by sliding the members 432 and 434 inside the tube to different positions. Accordingly, high-quality, novel optical lens elements, with pronounced spherical curvature, with pitch power correction and prescribed lens, and mounted on goggle frames adapted for use with them, are provided. The present invention has been described in connection with various embodiments and examples. However, the invention to be protected is defined by the following claims and equivalents thereof recognized in the law.

Claims (49)

1. CLAIMS 1. A lens element adapted to be mounted on products for ophthalmological use, the lens element having a spherical surface with a radius of curvature of less than about 35 mm, said lens element being adapted to be positioned such that a center The curvature of the lens element is located in the centroid of rotation of the eye, in which the lens element is large enough to provide a field of view, greater than 55 ° in the temporal direction from the forward line of sight and has a penetration power in the range of at least about +4 D to ~ 6 D.
2. 2. The lens element according to claim 1, characterized in that the lens element is a selected single-vision lens element. a series of lens elements having penetrating power from at least about +2 D to -2 D and about the same radius of curvature.
3. 3. A series of ophthalmological lens elements, each lens element having a spherical front surface which is approximately concentric with the centroid of rotation of the eye in the position of use; approximately the same radius of curvature which is essentially a single value selected from the series in the range of 25 to 50 mm + 1 mm; and in which the lens elements of the series have several powers of penetration of common prescription.
4. 4. The series of ophthalmological lens elements according to claim 3, characterized in that the lens elements have penetration powers of at least about +4 D to -6 D.
5. 5. The series of ophthalmological lens elements in compliance with claim 3 or 4, characterized in that the lens elements of the series are lens blanks or cut lenses having a back surface such that the lens element has a prescribed astigmatism correction and penetration power.
6. 6. The series of ophthalmological lens elements according to any of claims 3 to 5, characterized in that the rear surface lies between a barrel toroid and a screw toroid, both having the same main meridian and the same power throughout of said main meridian.
7. 7. The series of ophthalmological lens elements according to claim 6, characterized in that the surface astigmatism of said posterior surface at any point outside the main meridian is less than the larger surface astigmatism of the barrel toroid or the toroid screw in the same point.
8. 8. The series of ophthalmological lens elements according to claim 5, characterized in that the rear surface is defined such that the surface height Z of the lens element from a fronto-parallel plane at any point on the rear surface is a combination linear of the height of a barrel toroid, ZB, and the height of the thread toroid, Z being limited by the values of ZB and Zt.
9. 9. The series of ophthalmological lens elements according to claims 6 to 8, characterized in that the barrel toroid and the screw toroid each have a main meridian defined by a user recipe cyl.
10. 10. The series of ophthalmological lens elements according to claim 5, characterized in that the cross section of the posterior surface of the lens element along any meridian is circular.
11. 11. The series of ophthalmological lens elements according to claim 10, characterized in that the curvature of each circular meridian is equal to the instantaneous curvature of a corresponding meridian in the center of a conventional torus given by the recipe.
12. 12. The series of ophthalmological lens elements according to claim 10, characterized in that the posterior surface astigmatism correction is given by the surface height function z (r,?) Where and where R (0) R (90) R (?) F (0) sep? + R (90) cos2? is the radius of curvature along the meridian and the values R (0) and R (90) are the radii of curvature along the principal meridian.
13. 13. The series of ophthalmological lens elements according to claim 5, characterized in that the rear surface, together with the front surface, provide a non-zero penetration power and the rear surface is defined by the equation:
14. 14. An ophthalmological lens element having a surface that lies within a spherical shell defined by two concentric spheres having spokes whose lengths differ by no more than 2 mm, the smallest of the spokes being no more than 50 mm in length and in the which at least two points O and Q on the edge of the surface subtend an angle OPQ greater than 80 ° with respect to a center of the shell P.
15. 15. The ophthalmological lens element according to claim 14, characterized in that the The smallest of the spokes is approximately between 25 and 35 mm.
16. 16. The ophthalmological lens element according to claim 14 or 15, characterized in that the surface has a radius of about 33 mm ± about 2 mm.
17. 17. The ophthalmological lens element according to claims 14 to 16, characterized in that the length difference of the spokes is about 0.1 mm or less.
18. 18. The ophthalmological lens element according to claim 14, characterized in that the angle OPQ is greater than 90 °.
19. 19. The ophthalmological lens element according to claim 18, characterized in that the angle OPQ is greater than 100 °.
20. 20. The ophthalmological lens element according to any of claims 14 to 19, characterized in that the surface is the front surface of the lens element, and the rear surface is configured such that the lens element has a selected penetrating power. from ± 4 D to -6 D and a selected astigmatic correction.
21. 21. The ophthalmological lens element according to claims 14 to 20, characterized in that the lens element is mounted on a product for ophthalmological use so that the center of the lens is located approximately in the eye rotation centroid when the product for Ophthalmological use is in use.
22. 22. The ophthalmological lens element according to any of claims 14 to 21, such that for foveal vision the RMS Power Error is less than 3/8 D for eye rotation angles less than 30 °.
23. 23. The ophthalmological lens element according to claim 22, such that for foveal vision the RMS Power Error is less than D for eye rotation angles less than 40 °.
24. 24. The ophthalmological lens element according to claim 23, such that for foveal vision the RMS Power Error is less than% D for eye rotation angles greater than 40 ° and less than 50 °.
25. 25. The ophthalmological lens element according to any of claims 14 to 21, such that for peripheral vision where the eye is rotated and fixed at an angle of 30 ° temporarily, the RMS Power Error is less than 3/8 D for angles of ± 5 ° from the fixed position.
26. 26. The ophthalmological lens element according to claim 25, such that for peripheral vision where the eye is rotated and fixed at an angle of 30 ° temporarily the RMS Power Error is less than 0.65 D for angles of +10 of the fixed position.
27. 27. The ophthalmological lens element according to claim 26, such that for peripheral vision where the eye is rotated and fixed at an angle of 30 ° temporarily the RMS Power Error is less than 1.0 D for angles of ± 30. of the fixed position.
28. 28. An ophthalmological lens element including a spherical front surface which is approximately concentric with the center of eye rotation and having a base curve of 16 D ± approximately VL D and exhibiting relatively low RMS power error over approximately 40 degrees of eye rotation.
29. 29. The ophthalmological lens element according to claim 28, such that for foveal vision the RMS Power Error is less than 3/8 D for eye rotation angles less than 30 °.
30. 30. The ophthalmological lens element according to claim 29, such that for foveal vision the RMS Power Error is less than A D for eye rotation angles less than 40 °.
31. 31. The ophthalmological lens element according to claim 30, such that for foveal vision the RMS Power Error is less than% D for eye rotation angles greater than 40 ° and less than 50 °.
32. 32. The ophthalmological lens element according to claim 28, such that for peripheral vision where the eye is rotated and fixed at an angle of 30 ° temporarily, the RMS Power Error is less than 3/8 D for angles of + 5 ° of the fixed position.
33. 33. Product for prescribed ophthalmic use including a pair of ophthalmological lenses in which each lens will contain a sphere extending to the edges of the lens having average radii of no more than about 35 mm centered approximately e. the centroid of rotation of the respective eye, and has a maximum depth of cavity of at least about 8 mm.
34. 34. The product for ophthalmological use according to claim 33, characterized in that the maximum depth of cavity of each lens is at least about 10 mm.
35. 35. The product for ophthalmological use according to claim 33 or 34, characterized in that the front surface of each lens is generally spherical with a radius of curvature of no more than 35 mm and the rear surface is configured so that the lenses have selected penetration power of at least about +4 D to -6 D and prescribed astigmatic correction.
36. 36. The product for ophthalmological use according to claim 33, characterized in that the product for ophthalmological use further comprises a frame and in which each lens is selected from a series of lenses having penetrating power and astigmatic corrections commonly prescribed and in which the The radius of curvature of each element of the series is sufficiently similar to allow the use of any element of the series in the same spectacle frame.
37. 37. The product for ophthalmological use according to any of claims 33 or 36, characterized in that the radius of curvature of both lenses is around 33 mm.
38. 38. A series of negative-power ophthalmological lens elements having a surface lying within a spherical shell of a thickness no greater than 2 mm and a radius of no more than 50 mm, the lens elements of the series having thicknesses in its geometric centers which increase with the magnitude of the absolute value of the power.
39. 39. The series of negative power lenses according to claim 38, characterized in that the element has a thickness t at its center given by the function "B, (l-dFv) where n is the refractive index of the lens material, d is the distance from the back surface of the lens to the eye pupil, Fv is the posterior surface optical power, and Fj. is the front surface optical power defined as
40. 40. The product for prescribed ophthalmic use including a lens having a generally spherical curvature approximately centered on the centroid of rotation of the eye in which the lens extends horizontally from the nasal margins of the orbital region to the temporal margins of the orbital region, having said lens a concave posterior surface which clears the eyelashes and a penetrating power from the temporal edge to the nasal lens, varying by no more than 0.5 D of the prescribed power.
41. 41. A method for providing a product for prescribed ophthalmic use including the steps of providing a lens element having a front surface which lies within a spherical shell of a thickness no greater than about 2 mm and a radius of no more than about 35 mm. mm; and a rear surface configured such that the lens element has a prescribed penetration power and a prescribed astigmatism correction; and locating the lens element on the user so that the center of the spherical shell lies approximately at the center of rotation of the eye.
42. 42. The method according to claim 41, characterized in that the lens element is located by carving the lens element within a frame having a standard aperture corresponding to a radius of a spherical shell common to a series of lens elements having different penetration power, including the prescribed penetration power.
43. 43. The method according to claim 41 or 42, characterized in that the lens element is provided with a rear surface having a circular cross-section along any meridian that passes through its origin, and whose curvatures a long of those meridians are identical to the central curvatures of the. equivalent conventional toric.
44. 44. A spectacle frame suitable for use with a series of ophthalmological lenses, having a spherical surface of radius R between about 25 and 35 mm, and each lens of the series having the same R value, and a second surface selected to provide , in conjunction with the spherical surface, a range of common recipes, said frame supporting left and right lenses in the position of use so that the centers of the spherical surfaces are located approximately at the center of rotation of the left and right eyes, respectively.
45. 45. The spectacle frame according to claim 44, characterized in that it comprises tabs and edge portions for hooking the left and right lenses, in which the edge portion that hooks each lens is formed in the form of a closed curve lying on a sphere having a radius approximately equal to the radius of said spherical surface.
46. 46. The spectacle frame according to claim 45, characterized in that the most nasal point and the most temporal point of the closed curve subtend an arc greater than 90 ° with a vertex in the center of the spherical surface.
47. 47. The spectacle frame according to any of claims 44 to 46, characterized in that it includes a left leg, a right leg and a nose bridge.
48. 48. The spectacle frame according to claim 47, characterized in that the nose bridge is of adjustable length to allow horizontal adjustment of the lens spacing to locate the centers of the spherical surfaces in the centroids of the eyes.
49. 49. The spectacle frame according to claim 48, characterized in that it also includes hinges to support said lugs, said hinges being adapted to engage the spherical surface at the temporal edges of the respective lent-e.