NL2008054C2 - A trifocal intraocular lens. - Google Patents

Description

P100049NL00 A trifocal intraocular lens 5 Field of the invention

The invention relates to an intraocular lens (IOL).

Background of the invention

In the art, many attempts are made to provide a IOL with concentric annular 10 optical zones for reading distance and or intermediate vision. Examples of these types of lenses may be seen in U.S. Pat. Nos. 4,636,049; 4,418,991; 4,210,391; 4,162,172; and 3,726,587, in patent application US 2006/0212117, and in EP0590025B1 and US6,126,286. A problem of those IOL designs is the dependency on pupil size. Another problem of annular concentric designed IOLs are the ghost images and blur 15 due to the light directed to the macula at the annular zone transitions. Another drawback of such an IOL is the loss of contrast sensitivity. Contrast sensitivity determines the lowest contrast level which can be detected by a patient for a given size target. Normally a range of target sizes are used. In this way contrast sensitivity is unlike acuity. Contrast sensitivity measures two variables, size and contrast, while 20 acuity measures only size. Contrast sensitivity is very similar to auditory testing, which determines a patient's ability to detect the lowest level of loudness of various sound frequencies. The patient is asked to depress a button when the tone is just barely audible and release the button when the tone can no longer be heard. This procedure is used to test auditory sensitivity to a range of sound frequencies. If auditory testing 25 were evaluated in a similar way to visual acuity, all the sound frequencies would be tested at one high level of loudness.

The problem of pupil dependency of simultaneous vision multifocal performance is claimed to be diminished by a further embodiment of simultaneous vision multifocals that operates under the principles of diffraction. Examples of these 30 types of lenses were presented in U.S. Pat. Nos. 4,641,934 and 4,642,112. Due to the nature of diffractive optics, it was found that in the designs disclosed in these documents, at least 20% of the incoming light will be lost and patients suffer from halos and glare.

2

To solve the pupil independency problem, several attempts have been made, such as disclosed in US 4,923,296 which describes a lens divided into a series of substantially discrete near and distant vision zones. Not clear from this disclosure is how these vision zones should be made and or joined together. WO 92/06400 5 describes a aspheric ophthalmic lens. The surface zones are defined three dimensionally, forming a junctionless, continuous and smooth surface in conjunction with one another. In general, such a lens will suffer a large decrease of optical quality. US4921496 describes a rotation symmetric, radially segmented IOL. ThatlOL has no junctions at the surface, since the materials for each segment should have different 10 refractive indices to create the different optical powers.

Furthermore, an optical lens with a distance part and a near part is described in EP0858613(B1), US6409339(B1) and EP2219065(A1) from the current inventor. These documents disclose contact lenses, but also refer to IOL’s. A lens of this type differs from other known lenses in that the reading part is located within the 15 (imaginary) boundary of the distance part: The reading part is on or within the imaginary radius of the outer boundary of the distance part (Rv). If a partial part is used this is preferably made as a sector which extends from the centre of the lens. A reading part is thus recessed with respect to a distance part. This lens proved to have many possibilities. There is, however, room for further improvement. One of the 20 problems of the known intra ocular lenses is the occurrence of halo’s and other visual artefacts that can occur at various light conditions, especially under low light conditions W02010095938A1 of applicant relates to an ophthalmic lens comprising a main lens part, a recessed part, an optical centre, and an optical axis through said optical 25 centre, said main lens part having at least one boundary with said recessed part, said main lens part having an optical power of between about -20 to about +35 dioptre, said recessed part positioned at a distance of less than 2 mm from said optical centre and comprising a near part having a relative dioptre of about+ 1.0 to about +5.0 with respect to the optical power of said main lens part, said boundary or boundaries of said 30 recessed lens part with said main lens part form a blending part or blending parts, are shaped to refract light away from said optical axis, and have a curvature resulting in a loss of light, within a circle with a diameter of 4 mm around said optical centre, of less than about 15%.

3

Summary of the invention 5 The current invention seeks to improve IOL vision.

Hence, it is an aspect of the invention to provide an intraocular lens (IOL) comprising a lens with a main lens part having a surface, a recessed part having a surface which is recessed with respect to said surface of said main lens part, an optical centre, and an optical axis (R) through said optical centre of said main lens part, said 10 main lens part further having an optical power of between -20 and +35 dioptre, said recessed part positioned at a distance of less than 2 mm from said optical centre, said lens further comprising a central part which has a relative optical power of -2.0 to +2.0 dioptre with respect to said main lens part, wherein said central part fits within a circumscribing circle which has its centre at the optical axis and which has a diameter 15 of about 0.1-1.80 mm, said recessed part comprising in a circumferential direction a first optical region having a relative dioptre of +0.5 to +2.0 with respect to the optical power of said main lens part, and a second optical region having a relative dioptre of +0.5 to +2.0 with respect to the optical power of said first optical region, and said first and second optical regions are neighbouring regions joined via a blending zone.

20 It was found that the specific design provides a more comfortable vision. A

trifocal optic as described in this invention is desirable to have a balanced vision at each distance for infinity, intermediate and near objects. Thus, for instance far vision, computer work and reading can be optimized. It was shown that the three focal depths is an optimal trade off between loss of light in each of the three focal planes and the 25 required number of focal depths that are needed for daily activities.

Furthermore, it was found that using two recessed focal areas requires less deep and wide blending zones.

In an embodiment, the first and second optical regions have a different relative dioptre with respect to one another, in an embodiment the relative dioptres differ +0.5 30 to +1.75 with respect to one another. In particular, the relative dioptres differ between +0.75 up to +1.25. The small difference leads to a narrow blending zone between these optical regions.

4

In an embodiment, said lens has a lens circumference, and said first and said second region each extend from said central part to said lens circumference.

In an embodiment, said recessed part is bounded at opposite ends by a first and second meridian line to result in a circle sector, said meridian lines having an angle of 5 between 90 and 260 degrees, and said first optical region is bounded by one of said first and second meridian lines and a third meridian line and which are at an angle of 50-130 degrees and the second optical region is bounded by the other of said first and second meridian lines and said third meridian line and which are at an angle of 50-130 degrees.

10 In an embodiment, the first and second optical region are joined together by a blending part, in an embodiment said blending part is located between meridian lines, in an embodiment said meridian lines are at an angle of 1-30 degrees, in particular at an angle of 5-20 degrees.

In an embodiment, the first and second region make up said recessed part.

15 In an embodiment, the boundary or boundaries of said recessed lens part with said main lens part form a blending zone or blending zones that is or are shaped to refract light away from said optical axis.

In an embodiment, said blending zone between said first and second optical region is shaped to refract light away from said optical axis.

20 In an embodiment, the lens has a circumference, wherein said circumference is defined by said main lens part including an imaginary boundary as if said recessed part were not present, and said recessed part in radial direction extends up to said circumference.

In an embodiment, the recessed part extends within a sector of a circle that 25 circumscribes said main lens part and which sector has an angle of between 120 and 260 degrees.

The invention further relates to an intraocular lens (IOL) comprising a lens with a main lens part having a surface, a recessed part having a surface which is recessed with respect to said surface of said main lens part, said main lens part further having 30 an optical power of between -20 and +35 dioptre, wherein a first optical region with a relative dioptre of +0.5 to +2.0 with respect to the optical power of said main lens part and a second optical region neighbouring said first optical region and having a 5 relative dioptre of +0.5 to +2.0 with respect to the optical power of said first optical region making up said recessed part.

In an embodiment of this IOL, said first and second optical region are height-matched together by a blending zone. Thus, the blending zone joins the two optical 5 regions. Further blending zones may join the optical regions to the main lens part. In this embodiment, the two optical regions, not taking into account possible blending xones, almost completely make up the recessed part.

The invention further relates to an IOL as an add-on lens for placement into the sulcus, said IOL having a convex front lens comprising a main lens, and a concave 10 rear lens comprising a rear main lens having a recessed part having two different optical regions having different focal planes.

In this respect, concave is defined as such by an observer looking at the lens from the rear side.

The front lens is on the front surface of the add-on IOL, and the rear lens is on 15 the rear surface of the add-on IOL. The add-on IOL will usually be placed into the sulcus, in front of an existing lens.

In an embodiment, the concave rear lens has a main radius of curvature, and the recessed part has a recessed part radius of curvature that is larger than the main radius of curvature. In fact, if the recessed part has two neighbouring optical regions, each 20 region will have a different radius of curvature, but both these radii of curvature will be larger than the main radius of curvature.

Usually, an add-on IOL will be between -6 to +6 dioptre in order to correct remaining optical deficiencies of an existing lens. The add-on IOL may thus have a main lens that is 0 dioptre, but has the recessed part for correcting near or intermediate 25 vision. Furthermore, it can be used for correction additional optical deficiencies in an existing lens. Usually, the recessed part will provide 0 up to +3 Dioptre addition.

Thus, in fact the rear main lens will have the same features with respect to the recessed part as the front of the IOL front lens described above and in the embodiments of the drawings. The recessed part in the concave rear lens will have the 30 same blending zones as described for a convex lens. As the radius of curvature of a recessed part (or, in this particular case, recessed part with two regions) is larger than the main radius of curvature, the surface of the recessed part will again lower than the 6 surface of the main lens. Again, when going from the centre to the circumference of the main lens, the depth will thus increase.

In an embodiment, the main lens of the convex front lens further comprises a toric curvature for correcting corneal astigmatism.

5 In particular, the recessed part has the features of the IOL described above.

The term “substantially” herein, will be understood by the person skilled in the art. The term “substantially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially may also be removed. Where applicable, the term “substantially” may also relate to 90% or 10 higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%. The term “comprise” includes also embodiments wherein the term “comprises” means “consists of’.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily 15 for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

It should be noted that the above-mentioned embodiments illustrate rather than 20 limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The 25 article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

30 The invention further applies to an apparatus or device comprising one or more of the characterising features described in the description and/or shown in the attached drawings. The invention further pertains to a method or process comprising one or 7 more of the characterising features described in the description and/or shown in the attached drawings.

The various aspects discussed in this patent can be combined in order to provide additional advantages. Furthermore, some of the features can form the basis for one or 5 more divisional applications.

Brief description of the drawings

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding 10 reference symbols indicate corresponding parts, and in which:

Figure 1 schematically depicts an embodiment of the IOL in perspective view; Figure 2 shows the back side of the IOL of figure 1;

Figure 3 shows a front view of the IOL of figure 1;

Figure 4 shows the IOL of figure 1, with a sector cut out; 15 Figure 5 shows schematically an alternative embodiment of an IOL in perspective view with a concave, partially circumferential blending zone at the circumference of the lens;

Figure 5A a height plot, not scaled, along the radial direction indicated in figure 5; 20 Figure 6 shows the IOL of figure 5 in perspective view with a sector cut out;

Figure 7 shows schematically an alternative embodiment of an IOL in front view with the main leans 4 continuing at the circumference of the recessed part;

Figure 8 shows schematically a height map of the IOL of figure 7 along the indicated dotted curved line; 25 Figure 9 shows a perspective view of figure 7, and

Figure 9A a height plot, not scaled, along the radial direction indicated in figure 9.

The drawings are not necessarily on scale 30 Description of preferred embodiments

Figures 1-4 schematically depict an embodiment of an IOL that has a lens 1 with a main lens part 4 and a recessed part, here shaped as a recessed sector. This recessed sector has two sector parts 7 and 9 that have a dioptre that differ mutually, and that 8 also differs from the dioptre of the main lens part 4. The lens further has a central part 6 that is indicated with a circle line. If the dioptre of this part is the same as the dioptre of the main lens part 4, there of course is no transition. The transition from the central part 6 to the recessed part usually is continuous. Often, there may be a transition part.

5 The first derivative of the curvature of this transition part allows a continuous first derivative transition from the central part 6 to the recessed part.

The main lens part 4 and the recessed sectors 7 and 9 are mutually height-matched using blending zones 10, 10’ and 10”. The possible shape of these blending zones 10, 10’ and 10” are in detail discloses in WO2010095938 of the patentee, 10 mentioned above and incorporated by reference as if fully set forth in this description.

In the embodiment of figures 1-4, the recessed parts 7, 9 in radial direction, this is the direction from the centre of the lens 1 to the circumference of the lens 1, continues all the way up to the circumference of the lens 1. In that way, no blending zone is required at that circumference. In this embodiment, the height of the lens is 15 adapted. The height is in particular selected in such a way that the total thickness of the lens is within manufacturing limits. In fact, the height and order of the recesses 7, 9 and the main lens part 4 are selected in such a way that the deepest recessed part of recessed parts 7, 9 at its circumference substantially fits the surface of haptic 2. In the embodiment shown, it can be seen in figure 1 that in this embodiment the 20 circumference of recessed part 7 is still a little higher than the surface of that haptic. In this embodiment, the height of recessed part 9 (almost) fits the height of the surface of haptic 2. If the lens, in particular near the haptic 2, becomes too thin (in other words, the surface of the recessed part 7 is too much below the surface of haptic 2), the IOL has insufficient structural integrity at that part. Again, in this embodiment of figures 25 1-6, the height is selected in such a way that the rim of recessed part 7 ends a little above the surface level of the haptic 2.

Figure 3 clearly shows a front view of the three blending zones 10, 10’, 10”. This view clearly shows that in this embodiment, the blending zones 10, 10’, 10” are not purely bounded by meridians that define the borders of the blending zones. It was 30 found, as also described in already mentioned W02010095938, that when tooling is used to produce the IOL, that the tooling speed allows the blending zone to be very narrow close to the centre where the height difference is still small, and that near the circumference, where the height difference is relatively larger, the width of the 9 blending zone is relatively wider. Thus, the resulting blending zones 10, 10’, 10” in fact have a shape that can be described as the shape of a sharks’ teeth. This shape can also be used when producing the IOL using other techniques.

In figures 1 and 3, the width of each of the recessed sectors is indicated with a 5 and p, respectively, a and p can be equal or almost equal. In practice, these will be about 50-130 degrees. Variation in angle a and P is useful to divide the amount of light energy either equally or in a certain ratio between the foci for distance, intermediate and near to optimize the visual function for each focus such that there remains enough light energy in the respective focal areas of main lens part 4, and 10 recessed parts 7 and 9 to allow good vision.

In figures 5-6, another embodiment of an IOL is presented. Here, at the circumference, the recessed parts 7, 9 for instance cannot easily match the desired total lens thickness. Thus, a concave, circumferential, blending zone 11 is provided. At the start of this blending zone 11, the surface of the recessed parts 7 or 9 (or parts 7 15 and 9) radially remote from the lens circumference is below the required height. Usually, this is at or even below the height of the surface of haptic 2. Thus, the concave blending zone 11 matches the surface of the recessed part(s) to the surface of the haptic 2. The perspective of figure 6 may be a little deceptive in this. In figure 5A, a height profile, not in scale, is shown along the radial line indicated in figure 5.

20 In figure 7, a perhaps more classical approach to the circumferential matching question is provided. In this embodiment, at the circumferential part 13, the surface of the main lens part 4 continuous. Thus, in fact, as the dioptre of the recessed parts 7, 9 differs as earlier indicated from the dioptre of the main lens part 4, the surface of the recessed parts 7, 9 will be further below the (imaginary) surface of the main lens when 25 going from the edge of the central part 6 in radial direction to the circumference of the lens. Thus, close to circumferential part 13, the surface of the recessed part will be at its deepest below the surface of the main lens part 4. A (usually very steep and thus very small in a radial sense) blending part will match that deep surface to the surface of the circumferential part 13. A disadvantage of this approach is that often the 30 circumferential part 13 will in radial direction be wide, leading to loss of light in particular in low light conditions. Furthermore, artefacts may appear in the field of vision.

10

Just for clarity, figure 8 shows a height map, not on scale, along the indicated dotted line of figure 7. This height map, in fact, may be the same for the earlier embodiments. The embodiments largely only differ at the circumferential zone (the radially outer region) of the recessed part of recessed region.

5 In figure 9, a perspective view of the IOL of figure 7 is shown. In figure 9A, a height profile, not scaled, along the line indicated in figure 9 is shown. The dotted line is the continuation of the curvature of the central part 6 and in fact the curvature of main lens part 4.

It is to be understood that the above description is included to illustrate the 10 operation of the preferred embodiments and is not meant to limit the scope of the invention. The scope of the invention is to be limited only by the following claims. From the above discussion, many variations will be apparent to one skilled in the art that would yet be encompassed by the spirit and scope of the present invention.

Claims (10)

An intraocular lens (IOL) comprising a lens with a main lens portion having a surface, a recessed portion with a surface recessed relative to the surface of the main lens portion, an optical center, and an optical axis (R) through the optical center of the main lens part, wherein the main lens part further has an optical strength of between -20 and +35 diopter, the sunken part is laid at a distance of less than 2 mm from the optical center, the lens further comprising a central part that has a relative optical strength from -2.0 to +2.0 diopter relative to the main lens portion, the central portion fitting into a defining circle centered on the optical axis and having a diameter of about 0.1-1.80 mm, the recessed part comprising in a circumferential direction a first optical region with a relative diopter of +0.5 - +2.0 with respect to the optical strength of the main lens part, and a second optical region o with a relative diopter of + 0.5 - +2.0 with respect to the optical power of the first optical region, and the first and second optical regions are adjacent regions that are interconnected via a transition zone. The IOL of claim 1, wherein the first and second optical regions have a different relative diopter relative to each other, in one embodiment, the relative diopters differ +0.5 to +1.75 relative to each other. The IOL of claim 1 or 2, wherein the lens has a lens circumference, and the first and second regions each extend from the central portion to the lens circumference. 4. The IOL according to one or more of the preceding claims, wherein the countersunk part is bounded at opposite ends by a first and second meridian line to result in a circular sector, the meridian lines making an angle of between 90 and 260 degrees, and the first optical region is bounded by one of the first and second meridian lines and a third meridian line and which make an angle of 50-130 degrees and the second optical region is bounded by the other of the first and second meridian lines and the third meridian line and which make an angle of 50-130 degrees. 5. The IOL according to one or more of the preceding claims, wherein the first and second optical regions are interconnected by the transition zone, in one embodiment the transition zone is located between meridian lines, in an embodiment that are meridian lines at an angle of 1-30 degrees, in particular they make an angle of 5-20 degrees. The IOL according to one or more of the preceding claims, wherein the first and second regions together form the sunken part. 7. The IOL as claimed in one or more of the preceding claims, wherein the boundary or boundaries of the recessed portion with the main lens portion form or form a transition zone or transition zones that is shaped so that it bends or deflects light away from the optical axis. 8. The IOL according to one or more of the preceding claims, wherein the transition zone between the first and second optical region is shaped so that it bends light away from the optical axis. 9. The IOL according to one or more of the preceding claims, wherein the lens has a perimeter, the perimeter being defined by the main lens portion with an imaginary boundary as if the sunken portion was not present, and the sunken portion extends in radial direction on the perimeter. The IOL according to one or more of the preceding claims, wherein the recessed portion extends in a sector of a circle defining the main lens portion, which sector has an angle of between 120 and 260 degrees. 30 -o-o-o-o-o-