Title of Invention

A PROGRESSIVE ADDITION LENS AND A METHOD FOR FABRICATED A PROGRESSIVE ADDITION LENS

Abstract This invention relates to a progressive addition lens, comprising at least one surface, wherein said at least one surface is a composite of a progressive surface and a regressive surface.
Full Text Field of the Invention
The present invention relates to multifocal ophthalmic lenses. In particular,
the invention provides progressive addition lens designs and lenses in which
unwanted lens astigmatism is reduced as compared to conventional progressive
addition lenses.
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's"), are
used for the treatment of presbyopia. The progressive surface of a PAL provides far,
intermediate, and near vision in a gradual, continuous progression of vertically
increasing dioptric power from far to near focus, or top to bottom of the lens.
PAL's are appealing to the wearer because PAL's are free of the visible
ledges between the Zones of differing dioptric power that are found in other
multifocal lenses, such as bifocals and trifocals. However, an inherent disadvantage

in PAL's is unwanted astigmatism, or astigmatism introduced or caused by one or
more of the lens' surfaces. In hard design PAL's, the unwanted astigmatism borders
the lens channel and near vision zone. In soft design PAL's, the unwanted
astigmatism extends into the distance vision zone. Generally, in both designs the
unwanted lens astigmatism at or near its approximate center reaches a maximum that
corresponds approximately to the near vision dioptric add power of the lens.
Many PAL designs are known that attempt to reduce unwanted astigmatism

with varying success. One such design is disclosed in United States Patent No.
5,726,734 and uses a composite design that is computed by combining the sag
values of a hard and a soft PAL design. The design disclosed in this patent is such

that the maximum, localized unwanted astigmatism for me composite design is the
sum of the contributions of the hard and soft designs areas of maximum, localized
unwanted astigmatism. Due to this, the reduction in the maximum, localized
unwanted astigmatism that may be realized by this design is limited. Therefore, a
need exists for a design that permits even greater reductions of maximum, localized
unwanted astigmatism than in prior art designs.
Brief Description of the Accompaying Drawings
Fig. is an illustration of the distortion area of a progressive lens.
Fig. 2a is a cylinder contour of the progressive surface used in the lens of
Example 1.
Fig. 2b is a power contour of the progressive surface used in the lens of
Example 1.
Fig. 3 a is a cylinder map of the regressive surface used in the lens of
Example 1.
Fig. 3b is a power map of the regressive surface used in the lens of Example
1.
Fig. 4a is a cylinder contour of the composite surface of Example 1.
Fig. 4a is the power contour of the composite surface of Example 1.
Fig. 5 is the cylinder contour of the concave progressive surface of Example
2.
Fig. 6a is the cylinder contour of the lens of Example 2.
Fig. 6b is the power contour of the lens of Example 2.
Fig. 7a is the cylinder contour of a conventional lens.
Fig. 7b is the power contour of a conventional lens.
Fig. 8 is the cylinder contour of the concave progressive addition surface of
the lens of Example 3.
Fig, 9a is the cylinder contour of the lens of Example 3.
Fig. 9b is the power contour of the lens of Example 3.

Description of the Invention and its Preferred Embodiments
ID the present Invention, a composite surface is formed by combining the
designs of a progressive and a regressive surface. It is a discovery of the invention
that progressive lenses with reduced unwanted astigmatism may be constructed by
combining progressive addition and regressive surfaces into a composite surface.
In one embodiment, the invention provides a method for designing a
progressive addition surface comprising, consisting of, and consisting essentially of:
a.) designing a progressive surface having at least one first area of unwanted
astigmatism; b) designing a regressive surface having at least one second area of
unwanted astigmatism; and c.) combining the progressive surface and regressive
surface designs to form a composite progressive surface design, wherein the at least
one first and second areas of unwanted astigmatism are aligned. In another
embodiment, the invention provides a progressive addition lens comprising,
consisting essentially of, and consisting of a surface of the composite surface design
produced by this method.
By "lens" or "lenses" is meant any ophthalmic lens including, without
limitation, spectacle lenses, contact lenses, intraocular lenses and the like.
Preferably, the lens of the invention is a spectacle lens.
By "progressive addition surface" is meant a continuous, aspheric surface
having distance and near viewing or vision zones, and a zone of increasing dioptric
power connecting the distance and near zones. One ordinarily skilled in the art will
recognize that, if the progressive surface is the convex surface of the lens, the
distance vision zoni curvature will be less than that of the near zone curvature and if
the progressive surface is the lens' concave surface, the distance curvature will be
greater than that of the near zone.

By "area of unwanted astigmatism" is meant an area on the lens surface
having about 0.25 diopters or more of unwanted astigmatism.
By "regressive surface" is meant a continuous, aspheric surface having zones
for distance and neariviewing or vision, and a zone of decreasing dioptric power
connecting the distance and near zones. If the regressive surface is the convex
surface of the lens, the distance vision zone curvature will be greater than that of the
near zone and if the regressive surface is the lens' concave surface, the distance
curvature will be less than that of the near zone.
By "aligned" in relation to the areas of unwanted astigmatism is meant that
the areas of unwanted astigmatism are disposed so that there is partial or
substantially total superposition or coincidence when the surface are combined to
form the composite surface.
A number of optical parameters conventionally are used to define and

optimize a progressive design, These parameters include areas of unwanted
astigmatism, areas of maximum, localized unwanted astigmatism, channel length
and width, distance and reading zone widths, reading power width, and normalized
lens distortion. Normalized lens distortion is the integrated, unwanted astigmatism
of the lens below the optical center, primary reference point, divided by the dioptric
add power of the lens. Referring to Fig. 1, for progressive addition lenses, the
normalized lens distortion, DL can be calculated by the equation:

wherein: AL is the liens area; Nw is the near width; MA is the maximum;
localized, unwanted astigmatism (the highest, measurable level of astigmatism in an
area of unwanted astigmatism on a lens surface); and AP is the dioptric power of the

lens at y - -20 mm below the primary reference point. A1 is the area of the
intermediate zone where the unwanted astigmatism is less than 0.5 diopters and is
calculated by the equation:

where: Iw is width of the intermediate zone where the unwanted astigmatism is less
than 0.5 diopters; Dw and Nw are the widths of the distance (at y = 0) and near (at y
= -20 mm) viewing zones, respectively, where the unwanted astigmatism is less man
about 0.5 diopters; and IL is the length along the center of the channel between the
prism reference point and the narrowest width in the intermediate zone.
For purposes of Equation II, the near width and intermediate widths are not
synonymous with reading and channel width. Rather, whereas reading and channel
width are defined based on clinically relevant threshold for good vision, the near and
intermediate widths of Equation II are based on a 0.5 diopter astigmatic threshold.
In the lenses of the invention, the normalized lens distortion is significantly
reduced compared to conventional progressive addition lenses. Thus, in a preferred
embodiment, the invention provides progressive addition lenses comprising,
consisting essentially of, and consisting of at least one progressive addition surface
having a normalized lens distortion of less than about 300.
In the lenses of the invention, the dioptric add power, or the amount of
dioptric power difference between the distance and near vision zones, of the
progressive surface! design is a positive value and that of the regressive surface
design, a negative Value. Thus, because the add power of the composite surface is
the sum of the progressive and regressive surface designs' dioptric add powers, the

regressive surface design acts to subtract dioptric add power from the progressive
surface design.
It is known that a progressive addition surface produces unwanted
astigmatism at certain areas on the surface. The unwanted astigmatism of an area
may be considered a vector quantity with a magnitude and axis of orientation that
depends, in part, on the location of the astigmatism on the surface. A regressive
surface also has areas of unwanted astigmatism, the magnitude and axis of the
regressive surface astigmatism are determined by the same factors that are
determinative for the progressive surface astigmatism. However, the axis of the
regressive surface astigmatism typically is orthogonal to that of the progressive
surface astigmatism. Alternately, the magnitude of the regressive surface
astigmatism may be considered to be opposite in sign to that of the progressive
surface astigmatism at the same axis.
Thus, combining a progressive surface design with an area of unwanted
astigmatism with a regressive surface design with a comparably located area of
unwanted astigmatism reduces the total unwanted astigmatism for that area when the
two designs are combined to form a composite surface of a lens. The reason for this
is that the unwanted astigmatism of the lens at a given location will be the vector
sums of the unwanted astigmatisms of the progressive and regressive surface
designs. Because me magnitudes of the progressive addition and regressive surface
designs' astigmatisms have opposite signs, a reduction in the total unwanted
astigmatism of the composite surface is achieved. Although the axis of orientation
of the unwanted astigmatism of the regressive surface design need not be the same

as that at a comparable location on the progressive surface design, preferably the
axes are substantially the same so as to maximize the reduction of unwanted
astigmatism.

At least one area of astigmatism of the progressive surface design must be
aligned with one area of astigmatism of the regressive surface design to achieve a
reduction of unwanted astigmatism in the composite surface. Preferably, the areas
of maximum, localized unwanted astigmatism, or the areas of highest, measurable
unwanted astigmatism, of each of the surface designs are aligned. More preferably,
all areas of unwanted astigmatism of one surface design are aligned with those of the
other.
In another embodiment, the surfaces' distance and near zones, as well as the
channels are aligned. By aligning the surfaces in such a manner, one or more areas
of unwanted astigmatism of the progressive surface design will overlap with one or
more such areas on the regressive surface design. In another embodiment, the
invention provides a surface of a lens comprising, consisting essentially of, and
consisting of one or more progressive addition surface designs and one or more
regressive surface designs, wherein the distance vision zones, near vision zones and
channels of the progressive and regressive surface designs are substantially aligned.
In the lenses of the invention, the composite surface may be on the convex,
concave, or both surfaces of the lens or in layers between these surfaces. In a
preferred embodiment, the composite surface forms the convex lens surface. One
or more progressive addition and regressive surface designs may be used in the
composite surface, but preferably only one of each surface is used. In embodiments
in which a composite surface is the interface layer between the concave and convex
surfaces, preferably the materials used for the composite surface is of a refractive
index that differs at least about 0.01, preferably at least 0.05, more preferably at
least about 0.1

One ordinarily skilled in the art will recognize that the progressive addition
and regressive surface designs useful in the invention may be either of a hard or soft
design type. By hard design is meant a surface design in which the unwanted
astigmatism is concentrated below the surface's optical centers and in the zones
bordering the channel. A soft design is a surface design in which the unwanted
astigmatism is extended into the lateral portions of the distance vision zone. One
ordinarily skilled in the art will recognize that, for a given dioptric add power, the
magnitude of the unwanted astigmatism of a hard design will be greater than that of
a soft design because the unwanted astigmatism of the soft design is distributed over
a wider area of the lens.
In the lens of the invention, preferably, the progressive addition surface
designs are of a soft design and the regressive surface designs are of a hard design.
Thus, in yet another embodiment, the invention provides a lens surface comprising,
consisting essentially of, and consisting of a one or more progressive addition
surface designs and one or more regressive surface designs, wherein the one or more
progressive addition surface designs are soft designs and the one or more regressive
surface designs are hard designs. More preferably, the progressive addition surface
design has a maximum unwanted astigmatism that is less in absolute magnitude than
the surfaces' dioptric add power and, for the regressive surface design, is greater in
absolute magnitude.

The composite progressive surface of the invention is provided by first
designing a progressive addition and a regressive surface. Each of the
surfaces is designed so that, when combined with the design of the other surface or
surfaces to form the composite progressive surface, substantially all of the areas of
maximum, localized unwanted astigmatism are aligned. Preferably, each surface is

designed so that the maxima of the unwanted astigmatism areas are aligned and
when the surfaces' designs are combined to obtain the composite surface design, the
composite surface exhibits maximum, localized unwanted astigmatism that is at least
less than about 0.125 diopters, preferably less than about 0.25 diopters, than the sum
of absolute value of the maxima of the combined surfaces.
More preferably, each of the progressive and regressive surfaces is designed
so that, when combined to form the composite surface, the composite surface has
more than one area of maximum, localized unwanted astigmatism on each side of
the composite surface's channel. This use of multiple maxima further decreases the
magnitude of the areas of unwanted astigmatism on the composite surface. In a
more preferred embodiment, the areas of maximum, localized unwanted astigmatism
of the composite surface form plateaus. In a most preferred embodiment, the
composite surface has more than one area of maximum, localized unwanted
astigmatism in the form of plateaus on each side of the composite surface's channel.
Designing of the progressive and regressive surfaces used to form the
composite surface design is within the skill of one of ordinary skill in the art using
any number of known design methods and weighting functions. Preferably,
however, the surfaces are designed using a design method that divides the surface
into a number of sections and provides a curved-surface equation for each area as,
for example, is disclosed in United States Patent No. 5,886,766, incorporated herein
in its entirety by reference.
The surface designs useful in the lenses of the invention may be provided by
using any known method for designing progressive and regressive surfaces. For
example, commercially available ray tracing software may be used to design the
surfaces. Additionally, optimization of the surfaces may be carried out by any
known method.

In optimizing the designs of the individual surfaces or the composite
surface, any optical property may be used to drive the optimization. In a preferred
method, the near vision zone width, defined by the constancy of the spherical or
equivalent spherocylindrical power in the near vision zone may be used. In another
preferred method, the magnitude and location of the peaks or plateaus of the
maximum, localizod unwanted astigmatism may be used. Preferably, for purposes
of this method, the location of the peaks and plateaus is set outside of a circle having
an origin at x = 0, y = 0, or the fitting point, as its center and a radius of 15 mm.
More preferably, the x coordinate of the peak is such that x > 12 and the y mm.
Optimization may be carried out by any convenient method known in the art.
Additional properties of a specific lens wearer may be introduced into the design
optimization process, including, without limitation, variations in pupil diameter of
about 1.5 to about 5 mm, image convergence at a point about 25 to about 28 mm
behind the front vertex of the surface, pantoscopic tilt of about 7 to about 20
degrees, and the like, and combinations thereof.

The progressive and regressive surface designs used to form the composite
progressive surface may be expressed in any of a variety of manners, including and
preferably as sag departures from a base curvature, which may be either a concave
or convex curvature. Preferably, the surfaces are combined on a one-to-one basis
meaning that the sag value Z1 at point (x, y) of a first surface is added to the sag
value Z2 at the same point (x, y) on a second surface. By "sag" is meant the absolute
magnitude of the z axis distance between a point on a progressive surface located at

coordinates (x, y) and a point located at the same coordinates on a reference,
spherical surface of the same distance power.
More specifically in this embodiment, following designing and optimizing of
each surface, the sag values of the surfaces are summed to obtain the composite
surface design, the summation performed according to the following equation:

wherein Z is the composite surface sag value departure from a base curvature at
point (x, y), Z1 is the sag departure for the ith surface to be combined at point (x, y)
and a are coefficient? used to multiply each sag table. Each of the coefficients may
be of a value between about -10 and about +10, preferably between about -5 to
about +5, more preferably between about -2 and about +2. The coefficients may be
chosen so as to convert the coefficient of highest value to about + or -1, the other
coefficients being soiled appropriately to be less than that vaiue.
It is critical to perform the sag value summation using the same coordinates
for each surface so that the distance and near powers desired for the composite
surface are obtained; Additionally, the summation must be performed so that no
unpreacribed prism is induced into the composite surface. Thus, the sag values must
be added from the coordinates of each surface using the appropriate coordinate
systems and origins; Preferably, the origin from which the coordinate system is

based will be the prism reference point of the surface, or the point of least prism. It
is preferable to calculatc the sag values of one surface relative to the other along a
set of meridians by a constant or a variable magnitude before performing the
summation operation. The calculation may be along the x-y plane, along a spherical
or aspherical base curve, or along any line on the x-y plane. Alternatively, the

calculation may be a combination of angular and linear displacements to introduce
prism into the lens.
The distance and near vision powers for the progressive and regressive
surface designs are selected so that, when the designs are combined to form the
composite surface, the powers of the lens are those needed to correct the wearer's
visual acuity. The dioptric add power for the progressive addition surface designs
used in the invention each independently may be about +0.01 to about +6.00
diopters, preferably about +1.00 diopters to about +5.00 diopters, and more
preferably about +2.00 diopters to about +4.00 diopters. The dioptric add power of
the regressive surface designs are each independently may be about -0.01 to about
-6.00, preferably about -0.25 to about -3.00 diopters, and more preferably about -
0.50 to about-2.00 diopters.
In the case in. which more than one composite progressive surface is used to
form the lens, or the composite surface used in combination with one or more
progressive surface, the dioptric add power of each of the surfaces is selected so that
the combination of their dioptric add powers results in a value substantially equal to
the value needed to correct the lens wearer's near vision acuity. The dioptric add
power of each of the surfaces may be from about + 0.01 diopters to about +3.00

diopters, preferably from about +0.50 diopters to about +5.00 diopters, more
preferably about +1.00 to about +4.00 diopters. Similarly, the distance and near
dioptric powen for each surface are selected so that the sum of the powers is the

value needed to correct the wearer's distance and near vision. Generally, the
distance curvature for each surface will be within the range of about 0.25 diopters to
about 8.50 diopters.) Preferably, the curvature of the distance zone of a concave
surface may be about 2.00 to about 5.50 diopters and for a convex surface, about 0.5
to about 8.00 diopters. The near vision curvature for each of the surfaces will be

about 1.00 diopters to about 12.00 diopters.

Other surfaces, such as spheric, toric, aspheric and atoric surfaces, designed
to adapt the lens to the ophthalmic prescription of the lens' wearer may be used in
combination with, or in addition to, the composite progressive addition surface.
Additionally, the individual surfaces each may have a spherical or aspberical
distance vision zone. The channel, or corridor of vision free of unwanted
astigmatism of about 0.75 or greater when the eye is scanning from the distance to
the near zone and back, may be short or long. The maximum, localized unwanted
astigmatism may be closer to the distance or near viewing zone. Further,
combinations of any of the above variations may be used.
In a preferred embodiment, the lens of the invention has a convex composite
and concave progressive addition surfaces. The convex composite surface may be a
symmetric or asymmetric soft design with an aspherical distance viewing zone and a
channel length of about 10 to about 20 mm. The maximum, localized unwanted
astigmatism is located closer to the distance than the near viewing zone and
preferably is on either side of the channel. More preferably, the maximum, localized
unwanted astigmatism is superior to the point on the surface at which the dioptric
add power of the surface's channel reaches about 50 percent of the surface's dioptric
add power. The distance viewing zone is aspherized to provide additional plus
power to the surface of up to about 2.00 diopters, preferably up to about 1.00
diopters, more preferably up to about 0.50 diopters. Aspherization may be outside
of a circle centered at the fitting point and having a radius of about 10 mm,
preferably about 15 mm, more preferably about 20 mm.
The concave progressive surface of this embodiment is an asymmetrical, and
preferably ao asymmetrical, hard design, with a spherical distance viewing zone and
channel length of about 12 to about 22 mm. The distance viewing zone is designed
to provide additional plus power of less than about 0.50 diopters, preferably less
than about 0.25 diopters. The maximum, localized unwanted astigmatism is located

closer to the near viewing zone, preferably on either side of the lower tow-thirds of
the channel,
In yet another, embodiment, the lens of the invention has a convex composite
surface and concave regressive surface. In still another embodiment, the lens has a
convex composite surface, a regressive surface as an intermediate layer, and a
spherocylindrical concave surface. In yet another embodiment, the convex surface
is the composite surface, a regressive surface is an intermediate layer and the
concave surface is a conventional progressive addition surface. In all embodiments
it is critical that the distance, intermediate and near viewing areas of all surfaces
align so as to be free of unwanted astigmatism.
The lenses of tic invention may be constructed of any known material
suitable for production of ophthalmic lenses, Such materials are cither
commercially available or methods for their production are known. Further, the
lenses may be produced by any conventional lens fabrication technique including,
without limitation grinding, whole lens casting, molding, thermoforming,
laminating, surface casting, or combinations thereof. Preferably, the lens is
fabricated by first producing an optical preform, or lens with a regressive surface.
The preform may be produced by any convenient means including, without
limitation injection or injection-compression molding, thermoforming, or casting,
Subsequently, at least one progressive surface is cast onto the preform. Casting may
be carried out by any means but preferably is performed by surface casting
including, without limitation, as disclosed fa United States Patent Nos. 5,147,585,
5,178,800, 5,219,497, 5,316,702, 5,358,672, 5,480,600, 5,512371, 5,531,940,
5,702,819, end 5,793,465 incorporated herein in their entireties by reference.
The invention will be clarified further by a consideration of the following,
non-limiting examples.

Examples
Example 1
A soft design, convex progressive addition surface was produced as a sag
table wherein Z1 denoted the sag value departure from a base curvature of 5.23
diopters for the distance zone. In Figs. 2a and 2b are depicted the cylinder and power
contours for this surface. The add power was 1.79 diopters with a channel length of
13.3 mm and maximum, localized, unwanted astigmatism of 1.45 diopters at x = - 8
mm and y = - 8 mm. The prism reference point used was x = 0 and y = 0 and the
refractive index ("RI") was 1.56.
A hard design regressive surface desiga was produced for a convex surface
as a sag table wherein Z2 denoted the sag value departure from a base curvature of
5.22 diopters for the distance zone. In Figs. 3a and 3b are depicted the cylinder and
power contours for this surface. The add power was -0.53 diopter, the channel
length was 10.2 mm and the maximum, localized unwanted astigmatism was 0.71
diopters at x= -10 ram and y = -10 mm. The prism reference point used was x = 0
and y = 0 and the RI was 1.56.
A convex composite surface design was produced using Equation IE wherein
a1 = a2 = 1 to generate the sag value departures, to FIG8. 4a and 4b are depicted the
cylinder and power contours for the composite surface, which surface has a base
curvature of 5.23 diopters and an add power of 1.28 diopters. The composite surface
contains a single maximum, localized unwanted astigmatism area located on either
side of the channel. The magnitude of this astigmatism maximum was 0.87 diopters
and the channel length is 13.0mm. The composite surface's area of astigmatism was
located at x =-10mm and y =-18mm. The maximum astigmatism and normalized
distortion of the composite surface was significantly lower, without compromise of
the other optical parameters, than that of comparable dioptric add power prior art

lenses. For example, a Varilux COMFORT® lens has a maximum astigmatism
value and normalized distortion of 1.41 diopters and 361, respectively
for a 1.25 diopter add power as shown in Table 2. For a composite surface lens the
maximum astigmatism is 0.87 diopters and the normalized lens distortion of the lens
is calculated to be 265.
Example 2
A concave progressive addition surface was designed using a material
refractive index of 1.573, abase curvature of 5.36 diopters and an add power of 0.75.
diopters. FIG. 5 depicts the cylinder contours of this surface. The maximum,
localized astigmatism was 0.66 diopters at x = -16mm and y = -9 mm. The prism
reference point used was at x = 0 and y = 0.
This concave surface was combined with the convex composite surface from
Example 1 to form a lens with a distance power of 0.08 diopters and an add power
of 2.00 diopters. In the Table is listed the key optical parameters of this lens
(Example 2), and in FIGs. 6a and 6b is depicted the cylinder and power contours.
The maximum astigmatism is 1.36 diopters, significantly lower than prior art lenses
shown in the Table 1 as Varilux COMFORT® (Prior Art Lens 1 and FIGs. 7a and
7b. The normalized lens distortion of the lens is calculated to be 287, significantly
less than the prior art lenses of Table 3. Additionally, none of the other optical
parameters are compromised.
Example 3
In order to demonstrate the capability of the design approach of the invention
to optimize specific optical parameters, specifically the reading power width, a
concave progressive addition surface was designed using a material RI of 1.573, a
base curvature of 5.4 diopters and an add power of 0.75 diopters. In FIG. 8 is
depicted the cylinder contour of mis surface. The maximum, localized astigmatism

was 0.51 diopters at x = -15mm and y = -9 mm. The prism reference point used was
at x = 0 and y = 0.
This concave surface was combined with the convex composite surface from
Example 1 to form a lens with a distance power of 0.05 diopters and an add power
of 2.00 diopters. In the Table is listed the key optical parameters of this lens
(Example 3), and in Figs. 9a and 9b is shown the cylinder and power contours. The
maximum astigmatism is 1.37 diopters, significantly lower than the prior art lens
shown in Table 1 as Varilux COMFORT® - (Prior Art Lens 1 and FIGs 7a and 7b.
The normalized lens distortion of the lens is calculated to be 289, which is
significantly less than the prior art lenses of Table 3. The lower astigmatism of the
concave surface smoothens out the astigmatic contours and increases the reading
power width from 7.4mm to 8.6mm. None of the other optical parameters are
compromised.






WE CLAIM
1. An ophthalmic lens with a progressive addition surface, comprising a
composite surface of a progressive surface and a regressive surface,
wherein the composite surface a maximum, localized unwanted
astigmatism that is at least less than about 0.125 diopters than the sum of
an absolute value of the maximum, localized astigmatism of each of the
progressive and regressive and regressive surfaces.
2. A method for designing an ophthalmic lens with a progressive addition
surface comprising the steps of :

a) designing a progressive surface comprising at least one first area of
unwanted astigmatism;
b) designing a regressive surface comprising at least one second area
of unwanted astigmatism; and
c) combining the progressive and regressive surface designs to form a
composite progressive surface design, wherein the at least one first
and second areas of unwanted astigmatism are substantially
aligned.
3. The method as claimed in claim 2, wherein each of the progressive and
regressive surface designs is one of a hard design, a soft design, or a
combination thereof.

4. The method as claimed in claim 2, wherein each of the progressive and
regressive surface designs are hard designs.
5. The method as claimed in claim 2, wherein each of the progressive and
regressive surface designs are soft designs.
6. The method as claimed in claim 2, wherein a surface formed from the
composite surface design exhibits maximum, localized unwanted
astigmatism that is less than about 0.125 diopters than the sum absolute
value of the maximum, localized unwanted astigmatism of each of the
progressive and regressive surfaces.
7. The method as claimed in claim 2, wherein the composite surface design
comprises more than one area of maximum, localized unwanted
astigmatism on each side of the composite surface's channel.
8. The method as claimed in claim 2, wherein the progressive and regressive
surface designs are expressed as sag departures from a base curvature.
9. The method as claimed in claim 8, wherein the base curvature is a
concave or a convex curvature.
10.The method as claimed in claim 2, wherein in step c.) is carried out by
summing the progressive surface and regressive surface design sag values
according to the following equation:


wherein Z is the composite surface sag value department from a base
curvature at point (x,y), Zi is the sag departure for the ith surface to be
combined at point (x,y) and ai are coefficients.

Documents:

1289-kolnp-2003-abstract.pdf

1289-kolnp-2003-assignment-1.1.pdf

1289-kolnp-2003-assignment.pdf

1289-KOLNP-2003-CLAIMS-1.1.pdf

1289-kolnp-2003-claims.pdf

1289-KOLNP-2003-CORRESPONDENCE-1.1.pdf

1289-KOLNP-2003-CORRESPONDENCE-1.2.pdf

1289-kolnp-2003-correspondence-1.3.pdf

1289-kolnp-2003-correspondence.pdf

1289-kolnp-2003-description (complete).pdf

1289-kolnp-2003-drawings.pdf

1289-kolnp-2003-examination report-1.1.pdf

1289-kolnp-2003-examination report.pdf

1289-kolnp-2003-form 1.pdf

1289-kolnp-2003-form 18-1.1.pdf

1289-kolnp-2003-form 18.pdf

1289-kolnp-2003-form 2.pdf

1289-kolnp-2003-form 3-1.1.pdf

1289-kolnp-2003-form 3.pdf

1289-kolnp-2003-form 5-1.1.pdf

1289-kolnp-2003-form 5.pdf

1289-kolnp-2003-form 6-1.1.pdf

1289-kolnp-2003-form 6.pdf

1289-KOLNP-2003-FORM-27.pdf

1289-kolnp-2003-gpa-1.1.pdf

1289-kolnp-2003-gpa.pdf

1289-kolnp-2003-granted-abstract.pdf

1289-kolnp-2003-granted-claims.pdf

1289-kolnp-2003-granted-description (complete).pdf

1289-kolnp-2003-granted-drawings.pdf

1289-kolnp-2003-granted-form 1.pdf

1289-kolnp-2003-granted-form 2.pdf

1289-kolnp-2003-granted-specification.pdf

1289-kolnp-2003-others.pdf

1289-KOLNP-2003-PETITION UNDER RULE 137.pdf

1289-kolnp-2003-reply to examination report-1.1.pdf

1289-kolnp-2003-reply to examination report.pdf

1289-kolnp-2003-specification.pdf


Patent Number 247737
Indian Patent Application Number 1289/KOLNP/2003
PG Journal Number 19/2011
Publication Date 13-May-2011
Grant Date 10-May-2011
Date of Filing 10-Oct-2003
Name of Patentee ESSILOR INTERNATIONAL (COMPAGNIE GENERALE D'OPTIQUE)
Applicant Address 147 RUE DE PARIS, F-94220 CHARENTON-LE-PONT
Inventors:
# Inventor's Name Inventor's Address
1 MENEZES EDGAR V 6558 HIDDEN WOODS DRIVE, ROANOKE, VA 24018
PCT International Classification Number G02C
PCT International Application Number PCT/US2002/07943
PCT International Filing date 2002-03-14
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 09/832,236 2001-04-10 U.S.A.