JP2012093522A - Progressive multifocal contact lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a progressive multifocal contact lens designed to form two focuses for far sightedness and near sightedness on the retina of a human eye in a state in which a contact lens is put on the human eye.SOLUTION: A progressive multifocal contact lens 1 is constituted which has a lens optical part 2 having a far-sightedness part 3, a transition part 4, a near-sightedness part 5, and a near-sightedness auxiliary part 6 arranged concentrically from the center. The far-sightedness part 3 is arranged in the center of the lens optical part 2, and is an area for viewing a long distance. The transition part 4 is arranged at an outer periphery of the far-sightedness part, and has an optical power distribution continuously increasing from the optical power of the far-sightedness part 3. The near-sightedness part 5 is arranged at an outer periphery of the transition part 4, and is an area for viewing a short distance. The near-sightedness auxiliary part 6 is arranged at an outer periphery of the near-sightedness part 5, has an optical power distribution continuously decreasing the optical power of the near-sightedness part 5, and is provided so as to clearly obtain an image for near-sightedness. The image for near-sightedness can be clearly obtained since the near-sightedness auxiliary part 6 is formed.

Description

  The present invention relates to a contact lens, and more particularly to a progressive multifocal contact lens for both near and far.

  Conventionally, in a progressive multifocal contact lens used as a contact lens for presbyopia, a distance portion for viewing far and a near portion for viewing near are arranged in one optical portion (Patent Document 1). 2). FIG. 11 shows the configuration of a conventional progressive multifocal contact lens. As shown in FIG. 11, in the conventional progressive multifocal contact lens 10, the distance portion 12 and the near portion 14 are formed concentrically from the center portion to the outer periphery of the lens optical portion 11. Between the near portions 14, a transition portion 13 for continuously changing the power from the distance portion 12 to the near portion 14 is formed.

  FIG. 12 is a frequency distribution diagram on the BB axis of the progressive multifocal contact lens 10 of FIG. In the conventional progressive multifocal contact lens 10, the distance power is given by the distance portion 12 formed from the center of the lens optical portion 11 to a predetermined position, and the distance portion is moved toward the near portion 14 by the transition portion 13. The power is continuously increased from the power, and a desired near power is given by the near portion 14 so that the power is almost constant over the periphery of the lens optical portion 11. When such a progressive multifocal contact lens 10 is worn, the power of the transition portion 13 changes smoothly. Therefore, even if the distance area and the near area are allocated within a narrow range of the lens optical section 11, the distance use And near-field images can be good.

JP 2002-131705 A JP 05-181096 A

  By the way, the human eye is composed of two lenses, a cornea and a crystalline lens, as shown in FIG. 13A. Therefore, it is necessary to design the contact lens so that two focal points for distance and near are formed on the retina of the human eye in a state where the progressive multifocal contact lens 10, the cornea, and the crystalline lens are combined. For example, it is known that spherical aberration exists in the human eye based on actual measurement data and model eye data. FIG. 13A shows the structure of a model eye (human eye), and FIG. 13B shows measured data of spherical aberration of the human eye by Koomen et al. (1949), Invanoff (1953), Jenkins (1963), and model eye by Navarro. The measurement data of spherical aberration is shown. In FIG. 13B, the vertical axis indicates the incident light height, and the horizontal axis indicates the longitudinal spherical aberration.

The measured data for Koomen, Invanoff, and Jenkins are HLI Liou and NABrennan,
“The prediction of spherical aberration with schematic eyes”,
Ophthal.Phyisiol.Opt.Vol.16.No.4, pp.348-354,1996. Navarro's measurement data are R. Navarro, J-Santamaria, J. Bescos ”Accommondation-dependent model.
of the human eye with aspherics ”Vol.2, No8 / August 1985 / J.Opt.Soc.Am.A).

  The position indicated by the alternate long and short dash line S in FIG. 13A is the center of the optical part of the model eye (human eye). The light beam incident height, which is the vertical axis of FIG. 13B, is the height from the center of the optical part of parallel light rays that enter the human eye. As shown in FIG. 13B, it can be seen from the measurement data using the model eye and the actual measurement data using the human eye that the spherical aberration increases as the light incident height increases. In other words, the power is different in the central area and the peripheral area of the optical part of the human eye, the power is higher in the peripheral area than in the center of the optical part, and the human eye itself is a progressive multifocal lens for the central part and the peripheral part. It has become.

  When the above-described conventional progressive multifocal contact lens 10 is worn on this human eye, the contact lens and the human eye progressive lens overlap each other, particularly in the near portion, and the effect of the contact lens is lost. It became clear that there was a problem that became unclear. This is because the conventional progressive multifocal contact lens 10 is designed with the eyeglasses used away from the cornea.

  In view of the above, the present invention is a progressive multifocal contact lens designed so that two focal points for distance and near are formed on the retina of the human eye when the contact lens is worn on the human eye. The purpose is to obtain. Alternatively, it is an object of the present invention to obtain a progressive multifocal contact lens designed so that two near-focal points are formed on the retina of a human eye in a state where the contact lens and the cornea are combined.

  In order to solve the above problems and achieve the object of the present invention, the progressive multifocal contact lens of the present invention has a lens optical section in which regions having different powers are arranged concentrically. The lens optical unit includes a distance portion, a transition portion, a near portion, and a near assist portion from the center. The distance portion is an area that is disposed at the center of the lens optical portion and for viewing the distance. The transition portion is disposed on the outer periphery of the distance portion and has a power distribution that continuously increases from the power of the distance portion. The near portion is an area that is arranged on the outer periphery of the transition portion and for viewing the near portion. The near auxiliary part is disposed on the outer periphery of the near part and has a frequency distribution that continuously decreases from the frequency of the near part. The near-use auxiliary unit is provided to clearly obtain a near-use image.

  In the progressive multifocal contact lens according to the present invention, the near auxiliary portion is formed outside the near portion, whereby the amount of change in spherical aberration on the retina is reduced for the near focus, and the frequency of the human eye itself is reduced. Impact is mitigated. Needless to say, since the distance portion is formed at the center, the amount of change in spherical aberration on the retina is small at the distance focus.

  According to the progressive multifocal contact lens of the present invention, a near focus superior to the conventional one is formed on the retina, so that it is possible to clearly see both far and near.

FIG. 1 is a diagram showing a configuration of a progressive multifocal contact lens according to an embodiment of the present invention. FIG. 2 is a diagram illustrating a configuration of a lens optical unit of a progressive multifocal contact lens according to an embodiment of the present invention. FIG. 3 is a diagram illustrating a frequency distribution on the AA axis of the lens optical unit in FIG. FIG. 4 is a diagram illustrating a frequency distribution in the lens optical unit according to the first embodiment. FIG. 5 is a diagram showing vertical spherical aberration on the retina of the model eye when the progressive multifocal contact lens of Example 1 is worn on the Navarro model eye. FIG. 6 is a diagram illustrating a frequency distribution in the lens optical unit according to the second embodiment. FIG. 7 is a diagram showing vertical spherical aberration on the retina of the model eye when the progressive multifocal contact lens of Example 2 is worn on the Navarro model eye. FIG. 8 is a diagram illustrating a frequency distribution in the lens optical unit according to the third embodiment. FIG. 9 is a diagram illustrating a frequency distribution in the lens optical unit according to the fourth embodiment. FIG. 10 is a diagram illustrating a frequency distribution in the lens optical unit according to the fifth embodiment. FIG. 11 is a diagram illustrating a configuration of a lens optical unit of a conventional progressive multifocal contact lens. 12 is a diagram showing a frequency distribution on the BB axis of the lens optical unit in FIG. FIG. 13A is a diagram showing a configuration of a model eye (human eye), and FIG. 13B is a graph showing measured data of spherical aberration of the human eye by Koomen et al. (1949), Invanoff (1953), and Jenkins (1963). It is the figure which showed the calculation data of the spherical aberration of the model eye by Navarro. FIG. 14 is a diagram showing a configuration in a cross section in a state where a progressive multifocal contact lens is worn on a model eye. FIG. 15 is a diagram showing vertical spherical aberration on the retina surface of the model eye in a state where the conventional progressive multifocal contact lens is worn on the model eye.

  Hereinafter, an example of a progressive multifocal contact lens according to an embodiment of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following examples.

  First, before describing the embodiment of the present invention, spherical aberration when the conventional progressive multifocal contact lens 10 shown in FIG. 11 is worn on a Navarro model eye instead of the human eye will be described. 14 is a cross-sectional configuration diagram illustrating a state in which the progressive multifocal contact lens 10 is worn on the model eye, and FIG. 15 is a diagram illustrating vertical spherical aberration on the retinal surface of the model eye in the state of FIG. It is. The vertical axis in FIG. 15 is the incident light height (mm), and the horizontal axis is the spherical aberration (mm).

  As shown in FIGS. 11 and 14, the progressive multifocal contact lens 10 is worn on the model eye so that the center of the distance portion 12 is the center of the pupil. As can be seen from FIG. 15, the light incident on the center of the pupil forms the focal point of the distance portion 12 on the retina. However, as the incident light height increases, the absolute value of the spherical aberration increases monotonously. For this reason, the focal position formed by the near portion 14 of the progressive multifocal contact lens 10 becomes unclear. That is, with the conventional progressive multifocal contact lens 10, it is expected that the distance use will be clear, but the near use only provides an unclear image.

  In the conventional progressive multifocal contact lens 10, the reason why the near-intelligible and unclear image is generated is due to the spherical aberration of the human eye itself. As shown in FIG. 13B, the spherical aberration in the central region of the human eye is small. For this reason, the light incident on the human eye via the distance portion 12 is not significantly affected by the spherical aberration of the human eye itself. As a result, a focal point is formed on the retina by the power (refractive power) of the distance portion 12.

On the other hand, since the frequency increases in the region around the optical part of the human eye, the spherical aberration in the region around the optical part of the human eye is large as shown in FIG. 13B. For this reason, the light incident on the human eye via the near portion 14 is affected by both the power of the near portion 14 and the power of the human eye itself, and the focal position becomes unclear.
Hereinafter, as an embodiment of the progressive multifocal contact lens of the present invention, an example in which two focal points for distance and near are formed when worn on the human eye will be described.

<Progressive multifocal contact lens>
FIG. 1 shows a schematic configuration of a progressive multifocal contact lens according to an embodiment of the present invention, and FIG. 2 shows a schematic configuration of an optical unit of the progressive multifocal contact lens. As shown in FIG. 1, the progressive multifocal contact lens 1 has a lens optical part 2, a peripheral part 7, and an edge part 8 formed concentrically in order from the center, and the lens optical part 2 has a predetermined refractive power. It is comprised so that it may have. When the progressive multifocal contact lens 1 is worn on the human eye, the light incident through the lens optical unit 2 is focused on the retina.

  The progressive multifocal contact lens 1 according to this embodiment is formed of a disk-shaped member having a diameter of 8 to 15 mm, and the wearing surface (the surface to be worn on the human eye) is concave. The diameter of the hard contact lens is φ8 to 10 mm, and the diameter of the soft contact lens is φ13 to 15 mm. The lens optical unit 2 is composed of a disk-shaped member having a diameter of 6 to 10 mm, the hard contact lens has a diameter of 6 to 7 mm, and the soft contact lens has a diameter of 6 to 10 mm. The progressive multifocal contact lens 1 according to the present embodiment has a disc shape as shown in FIG. 1, but is not limited to this shape, and can be replaced with a non-disc shape such as an ellipse. is there.

  The material of the progressive multifocal contact lens 1 can be the same material as that of a general hard contact lens or soft contact lens, and is not limited in any way. Non-gas-permeable PMMA (polymethyl methacrylate) ), And various other materials known as hard contact lenses made of gas permeable (RGP) such as silicon / acrylate copolymers, hydrous materials such as PHEMA (polyhydroxyethyl methacrylate) and PVP (polyvinylpyrrolidone) In addition, in order to improve oxygen permeability, each material known as a silicone hydrogel contact lens mainly composed of a silicone-containing monomer or a siloxane macromer may be used.

  In the lens optical part 2 of the progressive multifocal contact lens 1, a distance part 3, a transition part 4, a near part 5 and a near auxiliary part 6 are formed concentrically in order from the center. FIG. 3 shows a frequency distribution on the AA axis of the progressive multifocal contact lens 1 of FIG. The vertical axis in FIG. 3 is the frequency (D), and the horizontal axis is the distance (mm) from the center of the lens optical unit. The vertical axis represents the distance power for the purpose of reference (0 point). The vertical axis may be read as addition power.

  In the progressive multifocal contact lens 1, a light ray incident on the human eye via the distance portion 3 is formed as a focal point on the retina of the human eye by the frequency applied to the distance portion 3. As a result, it is possible to clearly see the far-field image.

  The distance portion 3 is an area used when looking far away, and is formed in a circular shape at the center of the lens optical portion 2. If the diameter of the distance portion 3 is smaller than 0.5 mm, there is a problem that a clear distance image cannot be obtained, and if it is larger than 3.5 mm, a near area cannot be secured in the pupil. is there. Therefore, the distance portion 3 is preferably formed in a circular shape having a radius of 0.5 to 3.5 mm from the center. The pupil diameter is φ2 to 8 mm, usually about φ3 to 4 mm.

  The distance portion 3 is provided with a desired refractive power (distance power) capable of obtaining a clear field of view when looking far away. This distance power is a power prescribed in the same manner as the distance power in a normal contact lens.

  In the case of distance use, the frequency of the distance portion 3 is set so that the difference between the maximum value and the minimum value of spherical aberration (the amount of change in spherical aberration) is within 0.3 mm when the incident light height is in the range of 0 to 1.5 mm. Is preferably designed. As a result, the amount of change in spherical aberration is reduced for the far focus in a state where the lens optical unit 2 and the human eye are combined, and the far vision is clear.

  The transition part 4 is an area in which the frequencies of the distance part 3 and the near part 5 are smoothly changed, and is formed on the outer periphery of the distance part 3 with a predetermined width. If the width of the transition portion 4 is smaller than 0.5 mm, the frequency changes rapidly, and there is a problem that the image is likely to be doubled. If the width is larger than 2 mm, the regions of the distance portion 3 and the near portion 5 cannot be secured in the pupil. There is a problem. Therefore, the width of the transition portion 4 is preferably formed with a width of 0.5 to 2 mm.

  The near portion 5 is an area used when looking at the near side, and is formed on the outer periphery of the transition portion 4 with a predetermined width. If the width of the near portion 5 is smaller than 0.3 mm, there is a problem that a clear near-use image cannot be obtained. If the width is larger than 2 mm, the near auxiliary portion 6 protrudes from the lens optical portion 2. There is. Therefore, the near portion 5 is preferably formed with a width of 0.3 to 2 mm.

  In the near portion 5, a desired refractive power (near power) is given so that a clear field of view can be obtained when viewing near. This near power is a power prescribed in the same manner as a near power in a normal contact lens.

  The near vision assisting part 6 is an area for reducing the influence of the power of the human eye itself and making the near vision image clearer, and on the outer circumference of the near vision part 5 (the outermost circumference of the lens optical part 2). It is formed with a predetermined width. If the width of the near assisting part 6 is smaller than 0.5 mm, there is a problem that the effective near assisting part 6 cannot be obtained, and if it is larger than 2 mm, there is a problem that it cannot be accommodated in the lens optical part 2. Therefore, it is preferable that the near auxiliary portion 6 is formed with a width of 0.5 mm to 2 mm.

  It is preferable that the power in the near assisting unit 6 is configured to decrease between 0.25 and 5.00 D from the peak value of the near power to the outer periphery of the optical unit. By setting the reduction amount of the frequency in the near vision auxiliary unit 6 to 0.25 to 5.00 D, there is an effect of making the near vision image clearer.

  As shown in FIG. 3, in the lens optical unit 2 of the progressive multifocal contact lens 1, the combined region of the transition unit 4, the near-use unit 5, and the near-use auxiliary unit 6 is configured to have a convex shape. . That is, in the present embodiment, compared to the conventional progressive multifocal contact lens 10, an area where the power applied by the near portion 5 is reduced (near auxiliary portion 6) is formed on the outer periphery of the near portion 5. . A feature of the present invention is that an area for reducing the near vision frequency is provided on the outer periphery of the near vision portion 5 in order to provide a more effective near vision area. Note that the near portion 5 and the near auxiliary portion 6 may be collectively referred to as a near portion.

  In the progressive multifocal contact lens 1, light incident through the near portion 5 and the near auxiliary portion 6 also forms a focal point on the retina. In other words, by providing the near vision assisting part 6 for reducing the near vision power outside the near vision part 5, the human eye optical part peripheral area is larger than the human eye optical part central area. The influence of the power of the human eye itself is alleviated, the amount of change in spherical aberration in near vision is reduced, and a near focus is formed in the retina of the human eye. Thus, the clarity of near-use images is improved.

  In the case of near-use, the near-use part 5 is set so that the difference between the maximum value and the minimum value of spherical aberration (the amount of change in spherical aberration) is within 0.5 mm when the incident height is in the range of 2.5 to 3.5 mm. It is preferable that the power of the near auxiliary unit 6 is designed. As a result, the amount of change in spherical aberration on the retinal surface with respect to the near focus is reduced in a state where the lens optical unit 2 and the human eye are aligned, and the near image becomes clear.

  The near assisting unit 6 includes a first area 6a in which the near power in the near area 5 continuously decreases, and a second area 6b in which the power is increased again from the frequency decreased in the first area 6a. Has been. As can be seen from FIG. 13B, when the actual human eye and the Navarro model eye are compared, there is an example in which the change in spherical aberration at a position where the light incident height is high is small. That is, if the power applied in the near portion 5 is reduced too much, the light beam incident through the outermost peripheral region (near auxiliary portion 6) of the lens optical portion 2 is not formed as a focal point on the retina, and the field of view is not good. May become clear. Therefore, in the present embodiment, the frequency decreased in the first region 6a is increased again in the outermost peripheral region (second region 6b) of the lens optical unit 2.

  Note that various changes can be made to the amount of decrease in the frequency in the first region 6a and the amount of increase in the frequency in the second region 6b. In addition, the near assisting unit 6 is provided with the second region 6b that increases again the frequency reduced in the first region 6a, but it is only necessary to configure a region that decreases the frequency added in the near region 5, The near auxiliary part 6 may be only the first region 6a. That is, the transition portion 4, the near portion 5, and the near portion assist portion 6 are configured to have a frequency distribution in which the power has a convex shape on the plus side, thereby improving the clarity of the near-use image. To do.

Thus, in the progressive multifocal contact lens 1 according to the present embodiment, the power design is made in consideration of the power of the human eye. For this reason, two focal points for distance and near are formed on the retina, and it becomes possible to clearly see the distance and the near.
Below, the specific example of the progressive multifocal contact lens 1 of this embodiment example is shown.

[Example 1]
The progressive multifocal contact lens according to Example 1 will be described. The schematic configuration of the progressive multifocal contact lens according to Example 1 is the same as that shown in FIG. In Example 1, the diameter of the distance portion 3 in FIG. 2 is about 2 mm, the width of the transition portion 4 is about 0.8 mm, the width of the near portion 5 is about 0.6 mm, and the width of the near auxiliary portion 6 is about Designed to 1.6 mm. The parameters that determine the performance of the progressive multifocal lens of Example 1 are as follows.
Base curve (BC): 7.75 (mm)
Power (distance power): 0.00 (D)
Addition power (Add): +2.00 (D)
Center thickness (CT): 0.15 (mm)
Refractive index (N): 1.44

  FIG. 4 shows a frequency distribution (corresponding to the AA axis in FIG. 2) in the progressive multifocal contact lens of Example 1. In Example 1, the vertical axis indicates the frequency (D), and the horizontal axis indicates the distance (mm) from the center of the optical unit. In Example 1, the distance power is 0.00D, so the vertical axis may be read as addition power.

  The frequency distribution in the distance portion 3 is a substantially constant value of the distance power 0.00D, and the frequency distribution in the near portion 5 is configured to have a peak value of about +2.00 D (corresponding to the addition power). Is done. The frequency distribution in the transition unit 4 increases smoothly from the distance power to the addition power.

  The frequency distribution in the first region 6a decreases until the distance power falls below 0.00D, and the power is continuously increased until the frequency in the second region 6b becomes the same as the distance power (that is, 0.00D). It is said. With such a configuration, the power distribution of the progressive multifocal contact lens in Example 1 is higher (frequency plus direction) in the region where the transition portion 4, the near portion 5 and the near portion auxiliary portion 6 are combined. Has a convex shape.

  The progressive multifocal contact lens of Example 1 was worn on a Navarro model eye in the same manner as in FIG. 14, and the longitudinal spherical aberration on the retina of the model eye was examined. Table 1 shows the parameters of Navarro model eyes used as model eyes.

  FIG. 5 shows vertical spherical aberration on the retina of the model eye when the progressive multifocal contact lens of Example 1 is worn on the Navarro model eye. The vertical axis in FIG. 5 is the light incident height (mm) with respect to the center of the optical part of the model eye indicated by the one-dot chain line S in FIG. 14, and the horizontal axis is the spherical aberration (mm).

  As shown in a region a surrounded by a broken line in FIG. 5, the amount of change in spherical aberration is reduced between the incident light heights of 0 to 1 mm corresponding to the distance portion 3, and a focal point for distance is formed. Further, as shown in a region b surrounded by a broken line, the amount of change in spherical aberration is particularly reduced between the incident light heights of 2 to 3 mm corresponding to the region between the near portion 5 and the near assisting portion 6, A focal point is formed. Thus, when the progressive multifocal contact lens of Example 1 is worn, a clear image can be obtained not only for distance use but also for near use.

  In the first embodiment, in the near assisting unit 6, the second region 6b whose frequency increases again is formed on the outer periphery of the first region 6a configured to decrease the frequency from the near unit 5. did.

[Example 2]
A progressive multifocal contact lens according to Example 2 will be described. The schematic configuration of the progressive multifocal contact lens according to Example 2 is the same as that shown in FIG. In Example 2, the diameter of the distance portion 3 of FIG. 2 is about 2.4 mm, the width of the transition portion 4 is about 0.6 mm, the width of the near portion 5 is about 0.6 mm, and the width of the near portion auxiliary portion 6. Is designed to be about 1.6 mm. Parameters for determining the performance of the progressive multifocal contact lens of Example 2 are as follows.
Base curve (BC): 7.75 (mm)
Power (distance power): 0.00 (D)
Addition power (Add): +1.00 (D)
Center thickness (CT): 0.15 (mm)
Refractive index (N): 1.44

  FIG. 6 shows a frequency distribution (corresponding to the AA axis in FIG. 2) in the progressive multifocal contact lens of Example 2. The vertical axis and the horizontal axis are the same as those in the first embodiment. In Example 2, the distance power is 0.00D, so the vertical axis may be read as addition power.

  The frequency distribution in the distance portion 3 is a substantially constant value with the distance frequency being 0.00D, and the frequency distribution in the near portion 5 is such that the peak value is about +1.00 D (corresponding to the addition power). Composed. The frequency distribution of the transition unit 4 increases smoothly from the distance power to the near power.

  The frequency distribution of the near assisting unit 6 smoothly decreases from the near power of the near unit 5 and finally decreases to a frequency lower than the far power. The second embodiment is an example in which the addition power is smaller than that of the first embodiment, and the area for increasing the power again (corresponding to the second region 6b of the first embodiment) is not configured in the near-by auxiliary unit 6. With this configuration, the power distribution of the progressive multifocal contact lens in Example 2 has an upwardly convex shape in the region where the transition portion 4, the near portion 5 and the near portion auxiliary portion 6 are combined. The

  The progressive multifocal contact lens of Example 2 is worn on a Navarro model eye, and the vertical spherical aberration on the retina of the model eye is shown in FIG. The vertical axis and the horizontal axis are the same as those in FIG. As shown in a region a surrounded by a broken line in FIG. 7, the amount of change in spherical aberration is reduced between the incident light heights of 0 to 1 mm corresponding to the distance portion 3 and a focal point for distance is formed. Moreover, as shown in the area | region b enclosed with a broken line, the variation | change_quantity of spherical aberration reduces between the light incident heights of 2.5-3.5 mm corresponding to the area | region between the near part 5 and the near auxiliary | assistant part 6. Then, the focal point of the near portion 5 is formed.

[Example 3]
A progressive multifocal contact lens according to Example 3 will be described. The schematic configuration of the progressive multifocal contact lens according to Example 3 is the same as that shown in FIG. In Example 3, the diameter of the distance portion 3 of FIG. 2 is about 2.4 mm, the width of the transition portion 4 is about 0.7 mm, the width of the near portion 5 is about 0.6 mm, and the width of the near portion auxiliary portion 6. Is designed to be about 1.5 mm. Parameters for determining the performance of the progressive multifocal contact lens of Example 3 are as follows.
Base curve (BC): 8.00 (mm)
Power (distance for distance use): -3.00 (D)
Addition power (Add): +1.50 (D)
Center thickness (CT): 0.15 (mm)
Refractive index (N): 1.44

  FIG. 8 shows a frequency distribution (corresponding to the AA axis in FIG. 2) in the progressive multifocal contact lens of Example 3. The vertical axis and the horizontal axis are the same as those in the first embodiment. The frequency distribution in the distance portion 3 is a substantially constant value with the distance frequency being -3.00 D, and the frequency distribution in the near portion 5 has a peak value of -1.50 D (corresponding to addition power +1.50 D). It is comprised so that. The transition unit 4 continuously increases in power from the distance power to the near power.

  The frequency distribution of the near assisting unit 6 smoothly decreases from the near power (−1.50D) in the near unit 5 to −2.50D. With such a configuration, the power distribution of the progressive multifocal contact lens in Example 3 is higher (frequency plus side) in the region including the transition portion 4, the near portion 5, and the near auxiliary portion 6. Has a convex shape. In past research, it is known that the spherical aberration of the human eye is smaller than that of Navarro's model eye. For this reason, in Example 3, in consideration of the spherical aberration of the human eye, the amount of power reduction by the near assisting unit 6 is made smaller than in Examples 1 and 2. Even in this case, since the addition power of the near auxiliary unit 6 is small, it is expected that the amount of change in spherical aberration on the retina in the near use is small.

[Example 4]
A progressive multifocal contact lens according to Example 4 will be described. The schematic configuration of the progressive multifocal contact lens according to Example 4 is the same as that shown in FIG. In Example 4, the diameter of the distance portion 3 in FIG. 2 is about 2.2 mm, the width of the transition portion 4 is about 1.2 mm, the width of the near portion 5 is about 1 mm, and the width of the near auxiliary portion 6 is about Designed to 0.7 mm. Parameters for determining the performance of the progressive multifocal contact lens of Example 4 are as follows.
Base curve (BC): 7.75 (mm)
Power (distance power): 0.00 (D)
Addition power (Add): +2.00 (D)
Center thickness (CT): 0.15 (mm)
Refractive index (N): 1.44

  FIG. 9 shows a frequency distribution (corresponding to the AA axis in FIG. 2) in the progressive multifocal contact lens of Example 4. The vertical axis and the horizontal axis are the same as those in the first embodiment. The frequency distribution in the distance portion 3 is convex on the positive side in the central portion, and the frequency distribution in the near portion 5 is configured such that the peak value is +2.00 D (corresponding to addition power +2.00 D). The The transition unit 4 continuously increases in power from the distance power to the near power. Since the frequency distribution of the distance portion 3 is formed to have a convex shape on the positive side in the central portion, the amount of change in spherical aberration on the retina in the distance can be reduced, and the distance image can be more It can be seen clearly.

  The frequency distribution of the near assisting unit 6 smoothly decreases from the near power (+2.00 D) in the near unit 5, but finally remains at a higher frequency than the distance power. In the fourth embodiment, the amount of decrease in the addition power in the near assisting unit 6 is smaller than in the first to third embodiments, and in the near assisting unit 6, the frequency is increased again (corresponding to the second region 6b in the first embodiment). ) Is not configured. With such a configuration, the power distribution of the progressive multifocal contact lens in Example 4 is higher (frequency plus side) in the region where the transition portion 4, the near portion 5 and the near portion auxiliary portion 6 are combined. Has a convex shape. Moreover, since the addition power in the near vision auxiliary unit 6 is small, it is expected that the amount of change in spherical aberration on the retina in near vision will be small.

[Example 5]
A progressive multifocal contact lens according to Example 5 will be described. The schematic configuration of the progressive multifocal contact lens according to Example 5 is the same as that shown in FIG. In Example 5, the diameter of the distance portion 3 in FIG. 2 is about 1.6 mm, the width of the transition portion 4 is about 1.1 mm, the width of the near portion 5 is about 1 mm, and the width of the near auxiliary portion 6 is about Designed to 1.1 mm. Parameters for determining the performance of the progressive multifocal contact lens of Example 5 are as follows.
Base curve (BC): 7.75 (mm)
Power (distance power): 0.00 (D)
Addition power (Add): +2.00 (D)
Center thickness (CT): 0.15 (mm)
Refractive index (N): 1.44

  FIG. 10 shows a frequency distribution (corresponding to the AA axis in FIG. 2) in the progressive multifocal contact lens of Example 5. The vertical axis and the horizontal axis are the same as those in the first embodiment. The frequency distribution in the distance portion 3 is set to 0D in the center portion, and the frequency distribution in the near portion 5 is configured to have a peak value of +2.00 D (corresponding to addition power +2.00 D). The transition unit 4 continuously increases in power from the distance power to the near power.

  The frequency distribution of the near assisting unit 6 continuously decreases from the near power (+2.00 D) in the near unit 5, but finally remains at a frequency higher than the distance power. The fifth embodiment is an example in which a region for increasing the frequency again (corresponding to the second region 6b of the first embodiment) is not configured in the near assisting unit 6. The amount of decrease in the near-use auxiliary unit 6 in the fifth embodiment is smaller than those in the first to third embodiments but larger than that in the fourth embodiment. With such a configuration, the power distribution of the progressive multifocal contact lens in Example 5 is higher (frequency plus side) in the region including the transition portion 4, the near portion 5, and the near auxiliary portion 6. Has a convex shape. Even in this case, since the addition power of the near auxiliary unit 6 is small, it is expected that the amount of change in spherical aberration on the retina in the near use is small.

DESCRIPTION OF SYMBOLS 1 ... Progressive multifocal contact lens, 2 ... Lens optical part, 3 ... Distance part, 4 ... Transition part, 5 ... Near part, 6 ... Near use auxiliary part

Claims (9)

In a progressive multifocal contact lens having a lens optical unit in which regions having different frequencies are arranged concentrically, the lens optical unit includes:
A distance portion disposed at the center of the lens optical portion for viewing a distance;
A transition portion disposed on the outer periphery of the distance portion and having a frequency distribution that continuously increases from the frequency of the distance portion; and
A near portion for viewing the near, disposed on the outer periphery of the transition portion;
A near assisting part disposed on the outer periphery of the near part and having a frequency distribution that continuously decreases from the frequency of the near part,
A progressive multifocal contact lens, wherein the near assisting unit is provided to clearly obtain a near image. The progressive multifocal contact lens according to claim 1, wherein the amount of change in spherical aberration on the retinal surface is reduced for two focal points for distance and near. The near auxiliary part is disposed on the outer periphery of the near part, and has a first region for continuously decreasing the frequency from the near part toward the radially outward direction of the near part. The progressive multifocal contact lens according to claim 1, wherein the progressive multifocal contact lens is configured by a second region that is arranged on an outer periphery of the region and that increases again the power decreased in the first region. The distance portion is formed with a diameter of 0.5-3 mm, the transition portion is formed with a width of 0.5-2.0 mm, and the near portion has a width of 0.3-2. The progressive multifocal contact lens according to any one of claims 1 to 3, wherein the near auxiliary portion is formed in a range of 0.5 to 2.0 mm in width. The distance portion is formed with a diameter of 2 mm, the transition portion is formed with a width of 0.8 mm, the near portion is formed with a width of 0.6 mm, and the near auxiliary portion is formed with a width of 1.6 mm. Item 4. A progressive multifocal contact lens according to any one of Items 1 to 3. The amount of change in spherical aberration on the retina is 0.3 mm or less when the light incident height is in the range of 0 to 1.5 mm, and 0.5 mm or less when the light incident height is in the range of 2.5 to 3.5 mm. The progressive multifocal contact lens according to any one of claims 1 to 5. A clear near-use image is obtained by reducing the power return of the near-use part and the near-use auxiliary part from 0.25 to 5.00 D from the peak value of the near-use power to the outer periphery of the optical part. A progressive multifocal contact lens according to any one of claims 1 to 6. The progressive multifocal contact lens according to any one of claims 1 to 7, wherein a decrease width of the power decreased by the near assisting unit is smaller than an increase width of the power increased by the transition portion.   The progressive multifocal contact lens according to claim 1, wherein hydrogel or silicone hydrogel is used as a lens material.