MXPA99009764A - Methods for producing progressive addition lenses - Google Patents

Abstract

There is provided a process, for producing a progressive addition lens for a lens wearer, comprising the steps of:a) providing an optical preform;b) providing a mold for casting a surface onto the optical preform;and (c) positioning the preform in relation to the mold in order to provide the resulting lens with a cylinder axis desired for the lens wearer, wherein:either the optical preform or the mold has a predetermined first cylinder axis, a predetermined cylinder power and a predetermined first near vision zone position;and either the mold or the optical preform, respectively, has a second near vision zone position that is aligned with the lens wearer's near viewing pupil location.

Description

METHODS TO PRODUCE PROGRESSIVE ADDICTION LENSES FIELD OF THE INVENTION The present invention relates to multifocal ophthalmic lenses. In particular, the invention provides progressive addition lenses in which the undesirable lens astigmatism is reduced without compromising the functionality of the distance and channel widths through the intermediate and near vision zones, as compared to the progressive addition lenses. conventional BACKGROUND OF THE INVENTION The use of ophthalmic lenses for the correction of ametropia is well known. For example, multifocal lenses, such as progressive addition lenses ("PAL") are used for the treatment of presbyopia. The surface of a PAL provides far, intermediate and near vision in a continuous and gradual progression of dioptric increase that increases vertically from the far focus to the near focus, or from the top to the bottom of the lens. PALs are attractive to the user because PALs are free from visible edges between the different dioptric augmentation zones found in other multifocal lenses, such as bifocal and trifocal lenses. However, an inherent disadvantage in PAL lenses is the undesirable astigmatism of the lens, or the astigmatism introduced or caused by one or more of the lens surfaces. Generally, the undesirable astigmatism of the lens is located on either side of the near vision zone of the lens and at, or near, its approximate center, it reaches a maximum level corresponding approximately to the added dioptric increase of near lens vision . Generally, a PAL with an aggregate magnification of 2.00 diopters and a channel length of 15 mm will have a maximum localized unwanted astigmatism of approximately 2.00 diopters. The channel width of the lens will be approximately 6 mm in which the unwanted astigmatism is less than or equal to a threshold value of 0.75 diopters. A variety of lens designs have been tried in an attempt to reduce unwanted astigmatism or to increase the minimum channel width or both. However, the current most advanced progressive addition lenses provide only a minimal decrease in unwanted astigmatism while having larger areas in the peripheries of lenses that can not be used due to unwanted astigmatism. Therefore, there is a need for a PAL that reduces the maximum localized unwanted astigmatism, and that at the same time, provides an increase in the minimum channel width.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 a is a side view of a lens of the invention. Figure 1b is an astigmatism map of the lens of the Figure 1 a. Figure 2a is a side view of a lens of the invention. Figure 2b is an astigmatism map of the lens of the Figure 2a. Figure 3 is a side view of a lens of the invention. Figure 4a is a side view of a lens of the invention. Figure 4b is an astigmatism map of the lens of the Figure 4a. Figure 5a is a side view of a lens of the invention. Figure 5b is an astigmatism map of a progressive surface of the lens of Figure 5a. Figure 5c is an astigmatism map of a progressive surface of the lens of Figure 5a. Figure 5d is an astigmatism map of the lens of Figure 5a.

DESCRIPTION OF THE INVENTION AND ITS PREFERRED MODALITIES The present invention provides progressive addition lenses, as well as methods for their design and production, in which the maximum localized unwanted astigmatism is reduced, which is associated with a certain added diopter increase compared to the lenses of the prior art. Additionally, the width of distance, or width around the optical center of the lens that is free of 0.50 diopters or more of unwanted astigmatism and a minimum width of lens channel, are suitable for use by the lens user. For purposes of the invention, with "channel" is meant the vision corridor that is free of astigmatism of approximately 0.75 diopters or greater when the user's eye is scanning from the distance zone to the near and back zone. By "lens" or "lens" is meant any ophthalmic lens including, without limitation, eyeglass lenses, contact lenses, intraocular lenses and the like. Preferably, the lens of the invention is a lens for spectacles. It is a discovery of the invention that the maximum localized astigmatism can be reduced by combining two or more progressive addition surfaces each providing an added dioptric increase that is combined with that of the other surface or surfaces to produce a lens with a higher added dioptric increase than that of the individual surfaces. By "added dioptric increase" is meant the amount of dioptric increase difference between the near and far vision zones of a progressive addition surface. The lens of the invention exhibits less localized unwanted maximum astigmatism and a wider channel than would be expected by producing a lens with the same added dioptric magnification using only a progressive addition surface. Furthermore, it is a discovery of the invention that the use of more than one progressive addition surface ensures that the dioptric distance increase and the total added dioptric increase necessary to correct the user's vision are not compromised. It is even another discovery of the invention that when the areas of added dioptric magnification of the progressive surfaces are misaligned with respect to each other, the resulting total unwanted localized maximum astigmatism of the lens is less than the sum of the localized maximum unwanted astigmatism supplied by the individual added dioptric increases of each of the surfaces of progressive addition. By the term "progressive addition surface" is meant a continuous imperfect spherical surface having far and near vision zones and a zone of increasing dioptric magnification connecting the far and near vision areas. By the term "localized unwanted astigmatism" is meant the highest measurable level of astigmatism in an area of unwanted astigmatism on a surface of a lens. In one embodiment, the lens of the invention consists, consists essentially of, and consists of: a) a first progressive addition surface having one or more areas of localized unwanted maximum astigmatism, and a first added dioptric increase; and b) a second progressive addition surface having one or more areas of localized unwanted maximum astigmatism and a second added dioptric increase, the progressive addition surfaces being disposed in relation to each other so that a portion or all of the areas of maximum localized unwanted astigmatism are not aligned and where the added diopter lens magnification is the sum of the first and second aggregate dioptric increases. In another embodiment, the invention provides a method for producing a lens consisting of, consisting essentially of and, consisting of the steps of: a) supplying at least first and second progressive addition surfaces, having the first addition surface progressive one or more areas of undesired localized maximum astigmatism and a first added dioptric increase, and the second progressive addition surface having one or more areas of unforeseen maximum localized astigmatism and a second added dioptric increase and b) disposing the first and second surfaces of progressive addition such that a portion or the total of the unforeseen localized maximum astigmatism areas are not aligned and the added dioptric magnification of the lens is the sum of the first and second aggregate dioptric increases. By the term "misaligned" is meant that the surfaces, and therefore the areas of unwanted astigmatism, are positioned or arranged one in relation to the other so that a portion or the total of the areas of maximum astigmatism are not desired location of a surface does not substantially coincide with one or more of the unwanted maximum astigmatism areas located on the other surface. Preferably, the misalignment is such that none of the areas of maximum unwanted astigmatism located on one surface substantially coincide with those on the other surface. The progressive addition surfaces used in the lens of the invention can be misaligned by any of a number of methods. For example, the optical centers of the surfaces can be displaced, one with respect to the other, either laterally or vertically, or both. By "optical center" is meant the point on a surface intersected by the optical axis of the lens. One skilled in the art will recognize that, if the optical centers are displaced laterally, the minimum channel width is reduced by the same degree of displacement. Therefore, a progressive addition lens design using a lateral displacement preferably uses progressive addition surfaces with wider channel widths to compensate for the decrease in channel width caused by the displacement. Alternatively, if the optical centers of the surfaces are displaced vertically, the length of the channel will increase. By "channel length" is meant the distance along the central meridian of the surface between the optical center and the upper end of the near vision zone. Therefore, a design using such a displacement preferably uses progressive addition surfaces with shorter channel lengths to compensate. As another alternative, by keeping the optical centers of the progressive surfaces coincident with one another, the centers can be rotated with respect to each other. In a preferred embodiment, each surface is designed to be asymmetric around the center line of its channel. In this case, the areas of maximum unwanted localized astigmatism of the surfaces do not substantially coincide when rotating the optical axes around an axis joining the optical centers of the surface. By "asymmetric" it is meant that the magnification and astigmatism maps of the surface are asymmetric around the central meridian of the surface. The lateral and vertical displacements are made in such a way that dioptric increases in distance and close vision of the lenses are conserved. To properly take the introduction of the prismatic lens magnification, the displacements must be presented so that the optical center of a progressive addition surface moves along a curve that is parallel to the distance curve of the other progressive addition surface. In the case of rotations, the surfaces are rotated around their optical centers so that the distance and near increases are not substantially affected. One skilled in the art will recognize that the rotational misalignment may be in addition to the misalignment performed for purposes of reducing unwanted astigmatism. The amount of misalignment, or vertical displacement, lateral displacement or rotation of the optical centers, is a sufficient amount to prevent substantial overlap, or coincidence, of the areas of undesired maximum localized astigmatism of the progressive addition surfaces. More specifically, it is believed that the misalignment leads to an inequality in the direction of the astigmatic vectors associated with a surface relative to the corresponding astigmatic vectors of the other surface which results in the maximum unwanted localized total astigmatism for the final lens being less than if the vectors were aligned. The lateral or vertical displacement may be from about 0.1 mm to about 10 mm, preferably from about 1.0 mm to about 8 mm, more preferred from about 2.0 mm to about 4.0 mm. The rotational displacements may be from about 1 to about 40 degrees, preferably from 5 to 30 degrees, more preferred from 10 to about 20 degrees. As another additional alternative for misalignment, each surface can be designed so that the channel length of the surfaces is of different lengths. In this modality, the areas of maximum unwanted localized astigmatism of the surfaces do not align when the optical centers of the surfaces are aligned. As a result, unwanted astigmatism is reduced compared to a lens of the same total added dioptric increase. The greater the difference between the channel lengths, the greater the reduction in the maximum unwanted localized astigmatism. However, the channel lengths should not be so large as to produce an inequality in the near vision zones so that the close view of the lens user is not compromised. The lenses resulting from this modality will have a channel length that falls between the length of each surface and which depends on the added dioptric increase with which each surface contributed for the total aggregate dioptric increase of the lens. The difference in channel length between the surfaces may be from about 0.1 mm to about 10 mm, preferably from 1 mm to about 7 mm, more preferably from 2 mm to about 5 mm. Each of the progressive addition surfaces can be independently on the convex or concave surface of the lens or in a layer between the outer concave surface and the outer convex surface of the lens. Other surfaces, such as spherical and toric surfaces, designed to adapt the lens to the ophthalmic prescription of the lens user may be used in combination with, or in addition to, one or more of the progressive addition surfaces. For example, one of the progressive addition surfaces, preferably a concave surface, may be combined with a toric surface to provide a progressive toric surface having an added dioptric increase and a cylindrical increase in a particular axis. In the case of a concave toric progressive surface, the convex surface is preferably a non-toric surface. To provide the desired added dioptric increase and correct the astigmatism of the lens user, each of the near vision zones of the surfaces can be aligned with the position of the user's pupil during close observation, and the cylinder axis of the toric progressive surface can be placed to correspond with the user's prescription.

However, this method requires that a progressive toric surface be provided in each of the possible orientations of the 180-degree cylinder axes to provide a full prescription prescription scale. It is yet another discovery of this invention that the added dioptric increase decreases slowly by moving horizontally from the center of the near vision zone to the periphery of the surface. Given this fact, rotary misalignment of the near vision zones of the surfaces of + or - about 1 to about 25, preferably + or - about 1 to about 15, more preferably + or - about 1 to about 13 - can be used. degrees, as long as the desired aggregate dioptric increase of the lens is achieved. This discovery allows to limit the number of positions of the axis of the cylinder and the near vision zone used, so that it is not necessary to provide a progressive toric surface in each degree of the axis of the cylinder.

More specifically, a preferred method for producing a lens with a progressive toric surface is as follows. An optical preform is selected, the preform having a concave surface with a predetermined cylindrical increase, predetermined axis of the cylinder and a predetermined position of the near vision zone. By "optical preform" or "preform" is understood to mean an optically transparent shaped article capable of refracting light and having a convex surface and a concave surface, and which is suitable for use in producing eyeglass lenses. The increase of the cylinder is preferably the increase required by the lens user. The predetermined axis of the cylinder can be any axis of the cylinder, but is preferably within a set number of degrees of the axis of the cylinder required by the user of the lens. The cylinder axis of the preform may be within about 0 to about 25 degrees, preferably about 0 to about 20 degrees, more preferably about 0 to about 1 1 degrees of the required cylinder axis desired by the user of the lens. Preferably, the orientation of the selected cylinder axis is one of a group of orientations that is smaller than the 180 possible orientations, more preferably the axis being one of a group of approximately 20 orientations, most preferably the orientation is +1 1.25, +33.75, +56.25, +78.75, +101.25, +123.75, +146.25 and +168.75 degrees compared to the position of the three clock hours in the preform.

The near vision zone of the concave surface of the preform can be provided in any convenient position, but is preferably located so that its center is along the axis of the preform. 270 degrees of the preform. In a more preferred embodiment, the cylinder axes of the preform are provided at +11.25, +33.75, +56.25, +78.75, +101.25, +123.75, +146.25 or +168.75 degrees with respect to the position of the three clock hours on the preform, and the center of the near vision zone is located along the axis of 270 degrees, the position of the six hours of the clock. A convex surface for the lens is provided using a suitable mold to empty the surface onto the preform. Preferably, the mold is suitable for emptying a progressive surface. The near vision zone of the mold can be provided in any convenient position, but is preferably in a position that is aligned with the position of the close observation pupil of the lens user. Typically, this position will be on either side of the 270-degree axis, the six-hour position of the mold clock, depending on whether the right or left lens is being manufactured. Preferably, the position is within about 0 to about 20, more preferably about 5 to about 15, most preferably about 8 to about 10 degrees on either side of the 270 degree axis. The selected preform is placed or rotated in relation to the selected mold, so that the axis of the resulting lens cylinder will be that required by the user of the lens. For example, if the axis of the cylinder required by the user of the lens is 180 degrees for the left eye, and the cylinder increase of the optical preform is on the axis of 1.25 degrees, with the viewing area close to 270 degrees. , the preform is rotated, so that the axis of its cylinder falls along the axis of 180 degrees of the mold. This aligns the cylinder axis of the preform with respect to the cylinder axis required by the user. It will be recognized that the rotation of the preform relative to the mold also produces a rotating misalignment of the preform and near vision zones of the mold. However, this rotational misalignment is tolerable to approximately + or -25 degrees for the purposes of achieving the desired added diopter lens magnification. Thus, in yet another embodiment, the invention provides a method for producing a progressive addition lens for the user of the lens, and lenses produced by the method which comprises, consists essentially of, and consists of: a) providing a preform optics comprising at least one surface having a first predetermined axis of the cylinder, a predetermined cylindrical increase and a predetermined position of the first near vision zone; b) providing a mold for emptying a surface on the optical preform, the mold comprising a second position of near vision zone that is aligned with the position of the close observation pupil of the lens user; and c) positioning the preform relative to the mold to provide the resulting lens with a desired cylinder axis for the lens user.

In an alternative embodiment of the method, an optical preform is provided with at least one surface, preferably the convex surface, having a near vision zone, preferably a progressive addition surface. The near vision zone of this surface is aligned with the position of the close observation pupil of the lens user. A suitable mold is used to empty a toric surface on the preform, the mold having a predetermined axis of the cylinder, increase of the cylinder, and position of the near vision zone as described above. Thus, in an alternative embodiment, a method is provided for producing a progressive addition lens for the user of the lens, and lenses produced by the method which comprises, consists essentially of, and consists of: a) providing an optical preform which comprises at least one surface having a first position of the near vision zone which is aligned with the position of the close observation pupil of the lens user; b) providing a mold for pouring a surface onto the optical preform, the mold comprising a predetermined first axis of the cylinder, a predetermined cylindrical rise and a predetermined position of the second near vision zone; and c) positioning the preform relative to the mold to provide the resulting lens with a desired cylinder axis for the lens user. The person skilled in the art will recognize that any number of a wide variety of predetermined cylinder axes and positions of the near vision zone can be used. However, it is preferred that the predetermined cylinder axes and the positions of the near vision zone are selected from those shown in Table 1 for the prescribed prescription requirements of the lens cylinder axis.

TABLE 1 For the lenses and methods of the invention, the added dioptric increase of each of the progressive addition surfaces used in the invention is selected so that the sum of their added dioptric increases is substantially equal to the value needed to correct the sharpness of close view of the lens user. Additionally, the aggregate dioptric increase of each surface is selected in view of the maximum localized unwanted astigmatism associated with a determined near dioptric increase. Each of the added dioptric increases of the progressive addition surface can be independently from +0.01 diopter to approximately +3.00 diopter, preferably +0.25 diopter to approximately +2.00 diopter, more preferred from around +0.50 to approximately +1.50 diopter. Similarly, the distance and near dioptric increases for each surface are selected, so that the sum of the increases is the value needed to correct the near and distance vision of the user. Generally, the dioptric distance increase for each surface will be within the range of approximately 0.25 diopters to approximately 8.50 diopters. Preferably, the dioptric increase of the distance zone of the concave surface can be + or - from about 2.0.0 to about 5.50 diopters and for the convex surface + or -approximately 0.5 to 8.00 diopters. The dioptric increase of near vision for each of the surfaces will be approximately 1 .00 diopters to approximately 12.00 diopters. In embodiments in which cylindrical gain is used, the cylindrical increase can be from about -0.125 to about -6.00 diopters, preferably from about -0.25 to about -3.00 diopters. The progressive addition surfaces and lenses of the invention can be formed by any convenient method such as, without limitation, thermoforming, molding, polishing, casting or the like. In a preferred method, an optical preform having a progressive addition surface is used and a second progressive addition surface is emptied onto the preform. In a more preferred method, a preform of the concave surface is used which is a progressive addition surface with a spherical base increase and a cylindrical increase and a progressive addition surface is formed on the front surface by any convenient method, preferably by pouring and more preferably by surface casting. The invention will be further clarified by consideration of the following non-limiting examples.

EXAMPLES EXAMPLE 1 Referring to Figure 1 a, the lens 10 of the invention having a convex progressive addition surface 1 1 and a concave progressive addition surface 12 is shown. The surface 1 1 has a zone 13 of distance with a curvature of 6.00 diopters and a zone 18 close with a curvature of 7.00 diopters. The surface 12 has a distance zone 19 with a curvature of 6.00 diopters and a near zone 21 with a curvature of 5.00 diopters. The resulting distance increase of the lenses is 0.00 diopters and the added diopter lens increase is 2.00 diopters, with 1.00 diopters contributed by each of the surfaces 1 1 and 12. As shown in figure 1 a, the centers optic 16 and 17 convex and concave respectively, are displaced one with respect to the other by 4.0 mm.

Figure 1b is an astigmatism map of the lens 10 illustrating the misalignment of the surfaces. Areas 22 and 23 are those of unwanted astigmatism for surfaces 1 1 and 12 respectively. The locations 14 and 15 of the maximum localized astigmatism do not overlap and, therefore, are not additive. The value of 1.90 D of maximum unwanted astigmatism located for this lens is shown in Table 1 and is significantly less than the value of 2.20 D found in a conventional PAL of the same nearby dioptric increase.

TABLE 1 EXAMPLE 2 A lens with two surfaces of progressive addition, whose misalignment is 8.00 mm is used. The misalignment results in a maximum unwanted localized astigmatism reduction of 0.30 D compared to the prior art lens of Table 1.

EXAMPLE 3 As shown in Figures 2a and 2b, the lens 20 is shown with a concave progressive addition surface 25. Surface 25 has curvatures of the near and distance zone of 6.00 and 5.00 diopters, respectively. The convex surface 24 is also shown with curvatures of distance zone and close of 6.00 and 7.00 diopters. The optical center 27 of the surface 25 is rotated by an amount of 10 degrees with respect to the optical center 26 of the convex progressive surface 24. In Figure 2b, the astigmatism map of the lens 20 is shown. The areas 31 and 32 show areas of unwanted astigmatism for surfaces 24 and 25, respectively. Areas 28 and 29 of localized unwanted maximum astigmatism for surfaces 24 and 25, respectively, are also shown. Table 2 shows that the resulting lens has a localized unwanted maximum astigmatism of 1.90 diopters compared to 2.10 diopters for a prior art lens.

TABLE 2 EXAMPLES 4-6 The concave progressive addition surface of a lens is rotated 20, 30, and 40 degrees around its optical center with respect to the convex progressive addition surface. The rotations result in maximum unwanted localized astigmatisms of 1.85, 1.75 and 1.41 diopters, respectively, as shown in Table 2.

EXAMPLE 7 Figure 3 shows a concave progressive addition surface 34 positioned between the surfaces 33 and 35 of the lens 30. The lens 30 is made of an optical preform 38 having a refractive index of 1.60 and a pouring layer 39 having an index of refraction of 1.50. The convex surface 33 of the preform 38 has the optical center 36, a curvature of distance of 6.50 diopters and a near curvature of 8.50 diopters. The concave surface 34 of the preform 38 has an optical center 37, a distance curvature ("DC") of 6.50 diopters and a near curvature ("NC") of 0.50 diopters obtained with the formula: NC = DC - added increase xn? _ - 1.00 ni - n2 where neither is the refractive index of the optical preform 38 and n2 is the refractive index of the layer 39. The optical center 37 is displaced vertically downwards 4 mm with respect to the optical center 36. The concave surface 35 of the layer 39 includes a cylindric increase of -2.00 D to correct the astigmatism of the user. The lens 30 has an increase in distance of 0.00 diopters, a total dioptric aggregate increase of 3.00 diopters, which is reached by the added dioptric increase of 2.00 diopters of surface 33 and the added dioptric increase of 1.00 diopters of surface 34 combined. The maximum localized unwanted astigmatism is less than that of a conventional lens with an added dioptric increase in 3. 00 diopters.

EXAMPLE 8 In Figure 4a the lens 50 having a convex surface 51 and a concave surface 52 is shown. Surface 51 is a progressive addition surface with optical center 53. Surface 52 is a combination of toric progressive addition surface having an optical center 54 displaced vertically down 4 mm with respect to the optical center 53. Figure 4b shows the astigmatism map for the lens 50 showing the displacement. Areas 55 and 56 are the areas of unwanted astigmatism, with 57 and 58 being their respective localized maximum unwanted astigmatism areas, respectively, for surfaces 51 and 52. II is the toric axis for surface 52. The overlap of Progressive addition surfaces is such that although the near and distance vision zones are conserved, the location of the maximum astigmatism 57 and 58, located unwanted of each surface po coincide, and therefore, its effect is not additive .

EXAMPLE 9 The lens 60 is shown in Figure 5a in which a convex progressive-facing surface 61 is shown oriented to the left in combination with a concave progressive addition surface 62 oriented to the right. Each surface is shown individually in Figures 5b and 5c, respectively. The optical centers 63 and 64 of each of the surfaces are rotated so as to be optically aligned. In Figure 5d it is shown that the left and right orientation of the surfaces provide misalignment of areas 65 and 66 of unwanted astigmatism of surfaces 61 and 62, respectively. The maximum unwanted astigmatism located for the lenses 60 is 1 .70 diopters is indicated in Table 3.

TABLE 3 EXAMPLE 10 An optical preform is produced containing a spherical convex surface with a curvature of 6.00 diopters. The concave surface of the preform is a progressive toric surface with a base spherical curvature of 6.00 diopters, a cylindric increase of -2.00 diopters on an axis of 1.25 degrees, and a near vision zone with an added diopter increase of 1.00 diopters. The near vision zone is centered along the 270-degree axis of the preform. A progressive addition glass mold for a left lens is provided to surface-flush a layer of UV curable resin on the convex surface of the preform using conventional surface casting techniques. The mold has a base curvature of 6.00 diopters and an added diopter increase of 1.00 with the near vision zone along the axis of 262 degrees of the mold (8 degrees counterclockwise from the vertical). The preform is rotated counterclockwise with respect to the 11.25 degrees of the glass mold, so that the cylinder axis falls on the 0 degree axis of the mold, the desired axis for the lens. The rotating misalignment of the concave surface and the convex surface near the viewing areas will be 11.25 - 8 = 3.25 degrees. The resulting lens has a distance increase of 0.00 diopters, a cylindrical increase of -2.00 diopters on the 0 degree axis, and an added diopter increase of 2.00 diopters.

Claims (32)

NOVELTY OF THE INVENTION CLAIMS

1. - A method for producing a progressive addition lens for the user of the lens, characterized in that it comprises the steps of: a) providing an optical preform comprising at least one surface having a predetermined first axis of the cylinder, a predetermined cylindrical increase and a predetermined position of the first near vision zone; b) providing a mold for emptying a surface onto the optical preform, the mold comprising a second near vision zone that is aligned with the position of the close observation pupil of the lens user; and c) positioning the preform relative to the mold to provide the resulting lens with a desired cylinder axis for the lens user.

2. The method for producing a progressive addition lens for the user of the lens, further characterized in that it comprises the steps of: a) providing an optical preform comprising at least one surface having a first position of the near vision zone which is aligned with the position of the close observation pupil of the lens user; b) providing a mold for pouring a surface onto the optical preform, the mold comprising a predetermined first axis of the cylinder, a predetermined cylindrical rise and a predetermined position of the second near vision zone; and c) positioning the preform relative to the mold to provide the resulting lens with a desired cylinder axis for the lens user.

3. The process according to claim 1 or 2, further characterized in that the mold is a suitable mold to empty a progressive addition surface on the preform.

4. The method according to claim 1, further characterized in that the axis of the cylinder of the optical preform is within about 0 to about 25 degrees of the cylinder axis of the lens user.

5. The method according to claim 1, further characterized in that the surface of the optical preform is the concave surface.

6. The method according to claim 2, further characterized in that the surface of the optical preform is the convex surface.

7. The method according to claim 1, further characterized in that the near surface viewing area of the optical preform is located so that its center is along the 270-degree axis of the preform.

8. The method according to claim 1, further characterized in that the axis of the cylinder of the optical preform is provided in one of a group that is smaller than the 180 possible orientations of the axis.

9. The method according to claim 1, further characterized in that the axis of the cylinder of the optical preform is provided in one of +1 1.25, +33.75, +56.25, +78.75, +101.25, +123.75, +146.25 or +168.75 degrees with respect to the position of the three hours of the optical preform clock.

10. The method according to claim 8, further characterized in that the center of the near vision zone of the surface of the optical preform is located along the axis of 270 degrees of the optical preform.

11. The method according to claim 9, further characterized in that the center of the near vision zone of the surface of the optical preform is located along the axis of 270 degrees of the optical preform.

12. The method according to claim 1, further characterized in that the casting layer is poured on the convex surface of the optical preform.

13. The method according to claim 1, further characterized in that the near vision zone of the mold is in a position that is on either side of the 270 degree axis of the mold.

14. The method according to claim 13, further characterized in that the position of the near vision zone is within about 0 to about 20 degrees of the axis of 270 degrees.

15. The method for producing a progressive addition lens for the user of the lens, further characterized in that it comprises the steps of: a) providing an optical preform comprising a concave surface having a predetermined first axis of the cylinder, a predetermined cylindrical increase and a predetermined position of the first near vision zone; b) providing a mold for pouring a surface onto the convex surface of the optical preform, the mold comprising a second near vision zone that is aligned with the position of the close observation pupil of the lens user; and c) positioning the preform relative to the mold to provide the resulting lens with a desired cylinder axis for the lens user.

16. The process according to claim 15, further characterized in that the mold is a suitable mold to empty a progressive addition surface on the preform.

17. The method according to claim 15, further characterized in that the cylinder axis of the optical preform is within about 0 to about 25 degrees of the cylinder axis of the lens user.

18. The method according to claim 15, further characterized in that the near surface viewing area of the optical preform is located such that its center is along the 270 degree axis of the preform.

19. The method according to claim 15, further characterized in that the axis of the cylinder of the optical preform is provided in one of a group of approximately 20 possible orientations of the axis.

20. The method according to claim 15, further characterized in that the cylinder axis of the optical preform is provided in one of +1 1.25, +33.75, +56.25, +78.75, +101.25, +123.75, +146.25 or +168.75 degrees with respect to the position of the three hours of the optical preform clock.

21. The method according to claim 19 or 20, further characterized in that the center of the near vision zone of the surface of the optical preform is located along the 270-degree axis of the optical preform.

22. The method according to claim 15, further characterized in that the near vision zone of the mold is in a position that is on either side of the 270 degree axis of the mold.

23. The method according to claim 22, further characterized in that the position of the near vision zone is within about 0 to about 20 degrees of the axis of 270 degrees.

24. - The method for producing a progressive addition lens for the user of the lens, further characterized in that it comprises the steps of: a) providing an optical preform comprising a concave surface having a first predetermined axis of the cylinder that is within about 0 at about 25 degrees from the axis of the lens user's cylinder, a predetermined cylindrical rise and a predetermined position of the first near vision zone that is located so that the center of the near vision zone is along the axis of 270 optical preform grades; b) providing a mold for emptying a progressive addition surface onto the convex surface of the optical preform, the mold comprising a second near vision zone that is aligned with the position of the close observation pupil of the lens user; and c) positioning the preform relative to the mold to provide the resulting lens with a desired cylinder axis for the lens user.

25. The method according to claim 24, further characterized in that the first predetermined axis of the cylinder is within approximately 1 1 degrees of the cylinder axis of the lens user.

26. The method according to claim 24, further characterized in that the cylinder axis of the optical preform is one of +11.25, +33.75, +56.25, +78.75, +101.25, +123.75, +146.25 or +168.75 degrees. with respect to the position of the three hours of the clock of the optical preform.

27. - The method according to claim 26, further characterized in that the first predetermined axis of the cylinder is within approximately 1 1 degrees of the cylinder axis of the lens user.

28. The method according to claim 24, further characterized in that the near vision zone of the mold is in a position that is on either side of the 270 degree axis of the mold.

29. The method according to claim 28, further characterized in that the position of the near vision zone is within about 0 to about 20 degrees of the axis of 270 degrees.

30. The progressive addition lens produced by the method according to claim 1. 31.- The progressive addition lens produced by the method according to claim 15. 32.- The progressive addition lens produced by the process in accordance with claim 24.