JP4891262B2 - Soft contact lens - Google Patents

Description

The present invention relates to a technique for maintaining good wearing feeling and positional stability of a soft contact lens, and is particularly advantageously applied to a soft contact lens formed from a hydrous material.

  The contact lens is required to have a good wearing feeling that does not give a feeling of foreign matter during wearing, in addition to optical characteristics for exhibiting a desired vision correction function and the like. From this point of view, the inner surface of the contact lens superimposed on the cornea and the conjunctiva is generally a concave spherical surface in consideration of the spherical eyeball surface.

  By the way, it is known that the shape of a human cornea is not an accurate spherical surface but an aspherical surface whose curvature decreases from the central portion toward the peripheral portion. Therefore, several contact lenses having an aspherical concave inner surface shape closer to the cornea shape than the concave spherical surface have been proposed in the optical section. Examples thereof include those described in JP-B-49-18266, JP-A-62-502830, US Pat. No. 4,765,728, and the like. Also, the present applicant has previously proposed a soft contact lens having an inner surface shape more similar to the corneal shape in Patent Document 1 (Japanese Patent Laid-Open No. 6-194609).

  A contact lens having such an aspherical inner surface shape can be worn in a state where the inner surface is further along the eyeball surface than a contact lens having a spherical inner surface shape. Therefore, the wearing feeling is improved, and the optical characteristics can be improved by suppressing the adverse effect of the tear lens.

  However, as a result of many experiments and examinations by the present inventor, in such a contact lens in which the inner surface of the optical part is aspherical, there may be a problem in the stability of the position on the eyeball surface. I found out.

  Specifically, in a contact lens having an aspheric inner surface shape that approximates the corneal shape, the lens position on the eyeball surface is difficult to stabilize, particularly when the spherical lens power is large or immediately after wearing. It was confirmed that there was a tendency. Further, it has been confirmed that this tendency becomes more conspicuous particularly in a soft contact lens formed of a material having a high water content.

  Thus, the lack of positional stability of the contact lens on the eyeball surface during wearing, which is a problem newly discovered by the inventor as described above, may adversely affect the appearance and wearing feeling. Therefore, some measures are needed.

  The instability of the position of the contact lens as described above has not yet been fully elucidated, but as a result of the contact lens inner surface shape being more similar to the eyeball surface shape, a conventional concave spherical contact lens is used. Positioning action such as catching due to strong contact with a specific position of the eyeball surface considered to have occurred is not exerted, and the inner surface of the contact lens smoothly touches on the eyeball surface as a result, so that it slides on the eyeball surface. It is presumed that one of the causes is that it is easy to move. In addition, it is considered that the action of gravity is related to the contact lens with a large thickness. Furthermore, contact lenses with high water content are thought to be affected by changes in shape due to temperature changes. Especially, contact lenses in a low temperature state that have not risen to body temperature immediately after wearing, are separated from the eyeball surface. It is presumed that an increase in the size of the tear and excessive circulation of tears may be one of the causes of lens position instability.

  By the way, in order to cope with such a problem of instability of the lens position, it may be considered to adopt a sharp edge structure in which corners are formed at the outermost peripheral edge of the edge portion of the contact lens. For example, as shown in FIG. 9, the sharp edge structure is realized by making the rising portion 4 from the outer peripheral end of the inner surface of the lens at the edge portion of the contact lens 2 into an acute cross section having an angle of δ1, but for example, FIG. As shown in FIG. 10, it is also realized by forming an angle 8 of angle δ2 on the outer peripheral end surface of the contact lens 6 rising from the lens inner surface by a predetermined height (Japanese Patent Laid-Open No. 57-181525). reference). 9 and 10, A and B represent tangent lines of the inner and outer surfaces of the lens at the edge portion.

  However, when the inventors of the present application have studied, when a sharp edge structure in which the rising portion from the inner surface of the lens in the edge portion has an acute cross section or a corner portion is formed on the outer peripheral end surface of the lens is employed, the lens when the contact lens is worn is used. Although the position stability of the skin is improved, not only is the wearer feeling reduced by stimulation, but also the conjunctival epithelial disorder and the dryness are caused by the angle at the edge. It became clear that there was also a fear. Therefore, it is difficult to say that the sharp edge structure is an effective solution for improving the positional instability in the contact lens having the aspheric inner surface shape as described above.

  However, when a round edge structure having a smoothly continuous curved cross-sectional shape without corners is employed at the edge portion of the contact lens, problems such as a decrease in wearing feeling in such a sharp edge structure do not occur. However, it goes without saying that the round edge structure cannot provide any solution with respect to the problem of positional instability at the time of wearing in a contact lens having an aspheric inner surface shape as described above.

JP-A-6-194609 JP-A-57-181525

  Here, the present invention has been made in the background as described above, and the problem to be solved thereof is a sharp edge as described above in a contact lens having an aspherical inner surface shape close to a corneal shape. Contact without restricting the movement of the lens during wearing to an appropriate range without causing problems such as poor wearing feeling due to irritation of the corners such as when adopting the structure, and the occurrence of conjunctival epithelial disorder and dryness. It is an object of the present invention to provide a contact lens having a novel structure capable of expressing the positional stability of a lens together with an excellent wearing feeling exhibited by an aspherical inner surface shape.

  Hereinafter, embodiments of the present invention made to solve the above-described problems will be described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible. In addition, aspects or technical features of the present invention are not limited to those described below, but are based on the entire specification and drawings, or based on the inventive concept that can be grasped by those skilled in the art from these descriptions. It should be understood that

That is, a feature of the present invention is a soft contact lens which is made of a hydrous material and has an optical part at the center of the lens and a peripheral part on the outer peripheral side of the optical part. At least one of the inner surface of the optical part and the inner surface of the peripheral part is aspherical, while the inner surface of the peripheral part extends from the extension line of the inner surface of the optical part as it goes outward in the lens radial direction. The edge lift that gradually separates is set, the outer peripheral end surface of the lens is convex toward the outer peripheral side, has a smoothly continuous curved cross-sectional shape without corners, and the outer peripheral end surface of the lens and the center of curvature are connecting portion between the inner surface of the peripheral portion is set to the lens rear, distance to the lens inwardly in the lens radial direction from the outermost periphery edge of the lens: x only spaced apart from the position allowed was obtuse: the cross section of the α Are the corners with Jo, the separation distance: x is and obtuse angle 0mm <x ≦ 0.1mm: with alpha is 120 degrees ≦ alpha ≦ 0.99 degrees, the lens outer peripheral end surface, the It has a cross-sectional shape in which the radius of curvature: r is 0.03 mm ≦ r ≦ 0.05 mm throughout .

  In the soft contact lens having the structure according to the present invention, at least one of the inner surface of the optical part and the inner surface of the peripheral part has an aspherical shape closer to the corneal surface shape than the concave spherical surface. It can be made to conform to the shape, and an excellent wearing feeling can be obtained.

  In addition, in the soft contact lens of the present invention, the connecting portion between the lens outer peripheral end surface and the inner peripheral surface on the inner surface of the lens has an obtuse angular shape that is close to or in contact with the bulbar conjunctiva, for example, before the lens shape conforms to the eyeball surface. Even immediately after wearing, it is possible to suppress excessive inflow of tear fluid between the lens inner surface and the eyeball surface. Thereby, it is possible to improve the positional stability by suppressing the movement amount of the lens to an appropriate range. Furthermore, since the connecting portion between the inner peripheral surface of the lens and the outer peripheral end surface is formed into a square shape, the inner peripheral surface of the lens is sufficiently close to the eyeball surface in a wide area reaching the connecting portion formed into the square shape. Or it is made to contact | abut. Combined with such actions, that is, the positioning action by the proximity and contact of the inner surface of the lens to the eyeball surface, and the area where the inner surface of the peripheral part is close to or in contact with the eyeball surface, The positional stability at the time of wearing the contact lens can also be improved by the action of increasing the relative displacement resistance such as frictional resistance.

In particular, a corner portion is formed at a position close to the outermost peripheral end of the lens where the angular distance x between the angular connecting portion and the outermost peripheral end of the lens satisfies 0 <x ≦ 0.1 mm. Therefore, it is possible to more advantageously secure an area in the vicinity of or in contact with the eyeball surface on the inner surface of the peripheral portion. In addition, when viewed from the front in the axial direction, the rectangular connection portion is hidden so as to be inwardly covered from the outermost peripheral end of the lens, so that unnecessary connection of the connection portion to the bulbar conjunctiva is prevented. Is prevented. Furthermore, since the angular connection portion has an obtuse angle: α of 120 ° ≦ α ≦ 150 °, excessive connection of the connection portion to the bulbar conjunctiva can be avoided. In addition, since the corner portion is formed near the outermost peripheral end of the lens inner surface, it is possible to suppress the invasion of tears more than necessary. Furthermore, by making the outer peripheral end surface of the lens have a cross-sectional shape in which the radius of curvature r is 0.03 mm ≦ r ≦ 0.05 mm over the entire surface, it is possible to obtain a better wearing feeling during wearing. If the radius of curvature of the outer peripheral edge portion is smaller than 0.03 mm, the outer peripheral edge portion of the lens becomes sharp, which may cause irritation to the eyes. On the other hand, if the radius of curvature of the outer peripheral edge is larger than 0.05 mm, the wearing feeling may be impaired due to the feeling of the lens thickness. In addition, the cross-sectional shape of the outer peripheral end surface of the lens according to the present invention is not limited to an arc shape having a constant radius of curvature throughout, but a plurality of curves having different curvature radii within the above range are continuous. You may make it the curved shape connected to.

  In addition, the corner | angular part in this aspect should just be a line (line) in which a lens outer peripheral end surface and the inner surface of a peripheral part are connected obtusely without having a common tangent, and a shape is clear. . For example, in the longitudinal section of the lens, the surfaces that form the corners extending on both sides of the connecting portion do not have to be straight lines, and one or both may be curved lines.

  Further, the aspherical shape of the inner surface of the optical part and the inner surface of the peripheral part may be, for example, a curved surface made of a curve whose longitudinal section shape is represented by an appropriate multidimensional equation, or a cone such as an elliptical surface having a predetermined eccentricity. It may be a surface. In addition, the entire inner surface does not necessarily have a constant shape. For example, in a part of the inner surface of the peripheral portion, the longitudinal cross-sectional shape is a straight line, a concave shape, a convex shape, or an uneven shape toward the rear of the lens. It may be a curved surface. Furthermore, for example, the optical part may be divided into a central part and a peripheral part thereof, and the central part and the peripheral part may be formed of ellipsoidal surfaces having different eccentricities, thereby forming a non-spherical surface. good. In addition to the rotating body shape, for example, the inner surface of the optical part and the inner surface of the peripheral part may be formed in a non-rotating body shape provided with a prism, a cylinder, or the like.

  In addition, the soft contact lens structured according to the present invention has a curved continuous cross-sectional shape with no corners on the outer peripheral end surface of the lens, thereby stimulating the eyes (ball conjunctiva and eyelids) during wearing. Can be further relaxed. The curved cross-sectional shape may be any shape that does not have a corner, and does not necessarily have to be an arc shape having a constant curvature. For example, in the longitudinal cross-section, the lens crosses from the lens front side to the lens rear surface side. A curved cross-sectional shape whose curvature gradually changes according to

  In particular, in the present invention, by adopting the obtuse angle: α in the specific angle range as described above, it is possible to obtain very excellent effects in wearing feeling, lens moving range, and position stability during wearing. When the lid is obtuse and the obtuse angle α is smaller than 120 °, the corner becomes sharp and the irritation to the eye increases, which may reduce the feeling of wearing. On the other hand, if the obtuse angle α of the corner portion is larger than 150 °, the corner portion is close to a state where the corner portion is not formed, and it may be difficult to obtain sufficient lens position stability at the time of wearing. .

  In short, in a contact lens having a structure according to the present invention, the outer peripheral end surface of the lens has a convex curved cross-sectional shape with no corners, thereby causing defects at the edge portion of the sharp edge structure as described above (a feeling of wearing due to stimulation). The distance between the outer peripheral end of the lens and the inner surface of the lens is spaced radially inward from the outermost peripheral end of the lens: x is 0 mm <x ≦ By setting the cross-sectional angle of the corner of the connection portion to a specific obtuse angle (120 degrees ≦ α ≦ 150 degrees), even an aspherical contact lens can be used at the time of wearing. The position stability can be advantageously ensured, and the position stability during wearing can be remarkably improved as compared with the round edge structure.

  By the way, in the soft contact lens according to the present invention, for example, the inner surface of the peripheral portion is a concave curved line in the cross section in the lens radial direction, and the tangent line of the curved line and the outer peripheral end surface of the lens in the connecting portion. A configuration in which the obtuse angle: α is determined depending on an angle formed by the tangent line is preferably employed. In this aspect, the inner surface of the peripheral portion can be aspherical. In particular, since the inner surface of the peripheral part is recessed backward, it is possible to advantageously secure the amount of tear fluid retained between the cornea and the peripheral part.

That is, in the soft contact lens having the structure according to the present invention, any of the following modes (i), (ii), and (iii) can be adopted.
(I) The inner surface of the optical part is aspherical and the inner surface of the peripheral part is aspherical. (Ii) The inner surface of the optical part is aspherical and the inner surface of the peripheral part is other than an aspherical shape (iii). The inner surface of the optical part is spherical and the inner surface of the peripheral part is aspherical. Here, the aspherical shape in (i), (ii) and (iii) is closer to the corneal surface shape than the concave spherical shape. It has a concave shape.

  Furthermore, in the present invention, it is only necessary that at least one of the inner surface of the optical part and the inner surface of the peripheral part has such an aspherical shape. Therefore, in the present invention, for example, while the inner surface of the optical part is aspherical, at least a part of the inner surface of the peripheral part is a straight line in the lens radial direction cross section, and the straight line is formed at the connection part. A configuration in which the obtuse angle: α is determined by an angle formed by a tangent to the lens outer peripheral end surface is also preferably employed.

  In short, in the above (ii), an aspect in which at least a part of the inner surface of the peripheral portion is linear in the longitudinal section can also be adopted in the present invention. As such an embodiment, a part of the inner surface of the peripheral part may be a straight line in the longitudinal section, or the entire inner surface of the peripheral part may be a straight line in the longitudinal section. Thereby, the design and manufacture of the inner surface of the peripheral part can be facilitated.

  In the soft contact lens according to the present invention, a configuration in which the radius of curvature: r of the outer peripheral end surface of the lens is constant over the whole and the cross-sectional shape of the outer peripheral end surface of the lens is preferably an arc shape. .

  By setting such a constant radius of curvature: r, the lens outer peripheral end face can be made to have a smoother surface shape. As a result, it is possible to more effectively suppress contact stimulation to the cornea of the outer peripheral end surface of the lens and obtain an excellent wearing feeling.

  In the soft contact lens according to the present invention, a configuration in which the size of the edge lift: h is 0.04 mm ≦ h ≦ 0.12 mm is preferably employed.

  By setting the size of such an edge lift, it is possible to obtain more excellent effects in the wearing feeling of the contact lens, the moving range of the lens, and the position stability. If the size of the edge lift is smaller than 0.04 mm, there is a risk that the amount of tears retained in the peripheral portion will be too small, or the feeling of wearing will be reduced. On the other hand, when the size of the edge lift is larger than 0.12 mm, the corners are too far from the bulbar conjunctiva, and the effect of suppressing the flow of tears in and out by the corners and the effect of increasing the relative displacement resistance to the eyeball surface are obtained. There is a possibility that it is difficult to be effectively exhibited, and it is difficult to sufficiently improve the positional stability of the target contact lens.

In the soft contact lens according to the present invention, the lens size in the swollen state in 20 ° C. physiological saline: D ₂₀ to the lens size in the swollen state in 35 ° C. physiological saline: D ₃₅ : ΔD : ΔD = (D ₂₀ −D ₃₅ ) / D ₂₀ × 100 (%), the change rate is preferably 1% ≦ ΔD ≦ 5%.

  In a soft contact lens having such a temperature-shape change rate, there has been a strong possibility that the feeling of wearing is reduced immediately after wearing. On the other hand, in the present invention, even with a soft contact lens made of such a material having a large temperature-shape change rate, a good wearing feeling can be stably obtained immediately after wearing. Therefore, a large degree of freedom in selecting the lens material can be ensured without impairing the wearing feeling. When the temperature-shape change rate of the lens is larger than 5%, the shape before the lens shape changes and the shape after the change are too different, so even when the present invention is applied, the wearing feeling is always good. May be difficult to obtain. On the other hand, compared with the conventional structure, the improvement effect of good wearing feeling according to the present invention is recognized particularly advantageously when the temperature-shape change rate of the lens is 1% or more.

  In the soft contact lens according to the present invention, the inner surface of the optical unit is an ellipsoid having an eccentricity within a range of 0.2 to 0.7 and a vertex radius of curvature of 5.00 mm to 10.00 mm. A formed aspherical configuration can be advantageously employed.

  In such a soft contact lens having an inner surface of an optical part made of an elliptical surface, an excellent wearing feeling can be obtained by approximating the inner surface shape of the optical part to the shape of the central part of the cornea. In addition, position stability during wearing of the contact lens can be advantageously ensured while maintaining such excellent wearing feeling.

  In the present invention, it is not always necessary to form the inner surface of the optical unit with a single shape surface. For example, even when the inner surface of the optical part is formed of the above-described elliptical surface having a specific shape, only the central part of the optical part is 0.2 ≦ eccentricity (e) ≦ 0.7,5.00 mm ≦ vertical curvature radius (r ) ≦ 10.00 mm and the peripheral portion of the central portion is formed by an elliptical surface or the like that differs in at least one of the eccentricity and the vertex curvature radius. Two elliptical surfaces may be combined to form an aspheric surface on the inner surface of the optical unit. As described above, when both the central part and the peripheral part of the optical part are formed with an elliptical surface, not only the inner surface of the optical part but also the eccentricity of the inner surface of the peripheral part must be set within the above range. Is preferred.

  As is apparent from the above description, in the soft contact lens having the structure according to the present invention, the connecting portion between the lens outer peripheral end surface and the peripheral inner surface is formed by a corner portion having a specific shape, so that the optical portion of the contact lens or Positional stability during wearing of the contact lens can be advantageously achieved while maintaining a good wearing feeling due to the aspherical shape attached to the inner surface of the peripheral portion.

Sectional drawing which shows the contact lens as 1st embodiment. The front view of the contact lens. The principal part expanded sectional view of the contact lens. Cross-sectional explanatory drawing for demonstrating a shaping | molding die. Cross-sectional explanatory drawing which expanded the principal part of the mold forming die. The principal part expanded sectional view which shows the contact lens as 2nd embodiment. Sectional drawing which shows the contact lens as 3rd embodiment. The principal part expanded sectional view of the contact lens. Cross-sectional explanatory drawing which shows an example of the sharp edge structure of the contact lens which is not contained in this invention. Cross-sectional explanatory drawing which shows another example of the sharp edge structure of the contact lens which is not contained in this invention.

Explanation of symbols

10: Contact lens, 14: Front optical part, 16: Rear optical part, 18: Optical part, 20: Peripheral part, 22: Edge part, 24: Lens front face, 26: Lens rear face, 30: Annular lift part, 34: Lens outer peripheral surface, 36: front connection part, 38: rear connection part

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  First, FIGS. 1 and 2 show a specific structure example of a contact lens 10 as a soft contact lens having a structure according to the present invention. The contact lens 10 has a substantially spherical shell shape that is a dome shape as a whole, and is used by being worn while being superimposed on the surface of the eyeball including the cornea, as is well known. ing. In the contact lens 10 of the present embodiment, the lens central axis 12 is an optical axis, and the rotary lens shape around the lens central axis 12 is shown in FIG. Only show.

  Such a contact lens 10 is formed of a highly hydrous soft material having a moisture content of 50% or more, and thereby can effectively supply oxygen to the cornea by transmitting tear fluid through the lens. Furthermore, as a forming material of the contact lens 10, a material having a Young's modulus of 0.5 to 2.0 MPa is preferably adopted, thereby realizing a better wearing feeling and shape stability, The lacrimal fluid exchange action based on the surface tension and the pump action described later can be exhibited more advantageously. As such a soft material, for example, a soft material containing 2-hydroxyethyl methacrylate, methacrylic acid, pyrrolidone, a hydrophilic monomer of NN dimethylacrylamide, and silicone can be suitably used.

In addition, the contact lens 10 of the present embodiment has a lens size that changes due to a temperature change during wearing, and a lens size in a swollen state in 20 ° C. saline: D ₂₀ to 35 ° C. in a swollen saline solution lens size: the rate of change of the _{D 35: ΔD = (D 20} -D 35) / D 20 × 100 (%) is, it is desirable to set in a range of 1% ≦ ΔD ≦ 5%. The values of the lens sizes (D ₂₀ , D ₃₅ ) represent the lens outer diameter dimension: DIA.

  More specifically, in the central portion of the contact lens 10 of the present embodiment, a front optical part 14 and a rear optical part 16 which are circular in front view (axial view) are formed on the front and rear surfaces of the lens, respectively. By the front and rear surface optical parts 14 and 16, an optical part 18 having an appropriate lens power for correcting vision is formed at the center of the lens. The optical unit 18 has a circular shape centered on the lens center axis 12 in the front view shown in FIG. 2, and the outer diameter dimension Doz of the optical unit 18 is a corneal shape or size unique to the wearer. In general, φ5 to 9 mm is set.

  Further, the rear optical unit 16 as the inner surface of the optical unit 18 is arranged on the lens central axis 12 so that the rear optical unit 16 is substantially similar to the surface of the cornea to be mounted in the worn state (lower in FIG. 1). ), And preferably has a concave aspherical longitudinal cross section formed of an ellipse having an eccentricity of 0.2 to 0.7 and a radius of curvature of 5.00 to 10.00 mm. A curved surface. Thereby, the layer thickness dimension of the tear film formed between the rear optical part 16 and the surface of the cornea under the wearing state of the contact lens 10 is made substantially constant over the whole, and the lens action by the tear film is performed. Is reduced or avoided.

  As the longitudinal cross-sectional shape of the base curve surface, it is not always necessary to set an elliptical shape with a constant eccentricity or the like on the entire inner surface of the optical unit, taking into account the shape of the wearer's cornea, wearing conditions, etc. Is set as appropriate. For example, a plurality of circular and annular regions each having a predetermined width dimension in the radial direction may be set, and various curved shapes such as a conical curve shape having a different eccentricity may be set for each region. Alternatively, the rear optical unit 16 may be a spherical surface whose longitudinal section is a circular arc having a constant curvature. In particular, in the present embodiment, the rear optical unit 16 has a rotating body shape with the lens center axis 12 as the rotation center axis.

  On the other hand, the front optical unit 14 of the contact lens 10 is designed as a curved surface shape that can give a desired lens power in cooperation with the base curve surface 16 set as described above, and particularly in this embodiment. The center of curvature is set behind the lens on the lens center axis 12 to form a curved convex surface having a longitudinal sectional shape with an appropriate radius of curvature. The front optical part (front curve) 14 also takes into account the shape of the base curve surface 16, the required lens power, wearing conditions, etc., for example, an arc shape with a constant curvature radius, and the curvature radius is radial. Various curved convex shapes such as a conical curve shape that changes in the above can be appropriately employed. And the front optical part 14 in this embodiment is made into the rotary body shape which makes the lens center axis | shaft 12 the rotation center axis.

  The optical part 18 formed by the front and rear optical parts 14 and 16 is an area where an optical effect on the eyes of the wearer is expected, and is an outer peripheral part, in other words, a peripheral part 20 described later. In general, the boundary can be regarded as a change point of curvature on the longitudinal section on the front surface and the rear surface of the lens. However, for example, when the lens surface of the optical unit is designed with a longitudinal cross-sectional shape that gradually changes in the radial direction, or such a boundary is formed with a predetermined width in the radial direction and the optical unit 18 between the front and rear surfaces of the lens. The boundary between the optical part 18 and the peripheral part 20 on the front and rear surfaces of the lens does not necessarily have to be clearly defined as a line (line).

In addition, a peripheral zone 20 and an edge portion 22 are formed on the outer periphery of the contact lens 10 so as to surround the optical portion 18. In FIG. 3, the expanded sectional view of the peripheral part 20 and the edge part 22 is shown. The peripheral portion 20 has an annular shape with a predetermined width centered on the lens central axis 12 in the front view shown in FIG. 2, and the radial width dimension B _PZ of the peripheral portion 20 is equal to that of the optical portion 18. The size is from the outer peripheral edge to the edge 22 of the outer peripheral edge of the lens. The lens front surface 24 and the lens rear surface 26 of the peripheral portion 20 are connected by the edge portion 22.

Furthermore, the lens rear surface 26 of the peripheral portion 20 has an arcuate vertical cross-sectional shape having a predetermined curvature radius with a center of curvature set behind the lens. It should be noted that the radius of curvature: r _PB varies depending on the power (lens power) set in the optical unit 18, but is preferably set to r _PB ≦ 15 mm, and more preferably 2 mm ≦ r _PB ≦ 10 mm. The Thereby, a better feeling of wearing can be realized under the wearing state. If the value of the radius of curvature: r _PB is too large, the volume of the annular gap 40 (the amount of retained tears) to be described later will not be sufficiently secured. On the other hand, if r _PB is too small, Proximity and contact are close to the line state. As a result, the wearing feeling of the contact lens 10 may be reduced, the tear film may be divided, and the pumping action described below based on the deformation of the peripheral portion 20 may not be sufficiently exhibited.

  And since the lens rear surface 26 of the peripheral part 20 is made into the specific circular arc cross-sectional shape in this way, the annular convex part 28 which protrudes toward this cornea is formed in this lens rear surface 26 side. In the present embodiment, the annular convex portion 28 is formed with a substantially constant radial cross-sectional shape over the entire circumference of the contact lens 10 over the entire lens rear surface 26 of the peripheral portion 20.

  In addition, since the annular convex portion 28 that is convex toward the cornea is formed in this way, the lens rear surface 26 of the peripheral portion 20 is substantially the top of the annular convex portion 28 that is located in the radially intermediate portion of the peripheral portion 20. It is designed to be closest to the cornea. Furthermore, on the outer peripheral side of the proximity part to the cornea, the lens rear surface 26 of the peripheral part 20 is positioned gradually away from the cornea as it goes radially outward. Thus, in the present embodiment, the annular lift portion 30 that is opposed to the eyeball surface at a predetermined distance from the vicinity of the cornea adjacent to the cornea in the annular convex portion 28 of the peripheral portion 20 is positioned in the circumferential direction. It is formed in an annular shape continuously over the entire circumference. When the contact lens 10 is mounted, tears are introduced and held in the gap between the annular lift portion 30 and the opposing surface of the eyeball surface by the action of surface tension.

  The lift amount (separation distance) from the eyeball surface of the annular lift portion 30 is appropriately set in consideration of the material of the contact lens 10, the radius of curvature of the annular convex portion 28, the nature and amount of the tear fluid of the wearer, and the like. However, if it is too small, the amount of tear fluid introduced into the gap between the opposed surfaces of the annular lift 30 and the cornea 12 is reduced, while if it is too large, it is contacted by contact with the eyelid when blinking or the like. There is a possibility that the lens 10 may come off or be greatly displaced. Therefore, generally, the annular lift portion 30 extends from the rear optical portion 16 of the optical portion 18 of the contact lens 10 to the outer peripheral side with a substantially constant curvature radius (substantially the same curvature radius as that of the rear optical portion 16). An outer peripheral edge of the contact lens 10 between an extension line 32 and an extension line 33 extending from the lens rear surface 26 of the peripheral portion 20 to the outer peripheral side with a substantially constant radius of curvature (a curvature radius substantially the same as the radius of curvature of the lens rear surface 26). Part height (axial edge lift in the lens central axis direction): h is preferably set within a range of 0.04 mm to 0.12 mm in the swollen state during wearing. However, it is not an essential requirement in the present invention to provide an axial edge lift (h> 0) in such an annular lift portion 30. For example, the lens rear surface 26 of the peripheral portion 20 is formed along the extension line 32 of the rear optical portion 16 to set the edge lift to zero, or the edge lift is set to a negative value in consideration of the required characteristics for the contact lens. It is also possible to do.

  Further, the lens front surface 24 of the peripheral portion 20 has an arcuate vertical cross-sectional shape with a center of curvature set behind the lens and convex toward the lens front surface side having a predetermined radius of curvature. In particular, in the present embodiment, the inner peripheral edge portion is smoothly connected to the front optical portion 14 of the optical portion 18 with a common tangent line, and the thickness of the peripheral portion 20 gradually increases toward the outer peripheral edge portion of the peripheral portion 20. The thickness is set in consideration of the curvature radius of the lens front surface of the optical unit 18 and the curvature radius of the lens rear surface 26 of the peripheral portion 20 so as to be thin.

  The lens front surface 24 and the lens rear surface 26 are connected by the edge portion 22. The lens outer peripheral end surface 34 in the edge portion 22 has a curved cross-sectional shape that is convex toward the outer peripheral side of the lens in the longitudinal cross section, and is continuous over the entire outer periphery of the contact lens 10. Is formed. In addition, the lens outer peripheral end surface 34 is a convex surface that is smoothly continuous without a corner over the entire length from the connecting portion with the lens front surface 24 to the connecting portion with the lens rear surface 26 in the vertical cross section shown in FIG. The surface shape of the shape. However, the connection portion itself between the lens outer peripheral surface 34 and the lens rear surface 26 is a rear connection portion 38 having a corner as described later.

  Moreover, it is preferable that the lens outer peripheral end surface 34 has a cross-sectional shape with a curvature radius r of 0.03 mm ≦ r ≦ 0.05 mm over the entire surface. Thereby, a better wearing feeling can be obtained. In particular, in the present embodiment, the cross-sectional shape of the lens outer peripheral end surface 34 is a circular arc shape that is slightly smaller than a half circumference whose curvature radius r is constant throughout. However, the lens outer peripheral end face 34 does not necessarily have to be formed with a constant curvature radius. For example, a plurality of curves having different curvature radii are continuously connected, or a curved cross-sectional shape in which the curvature radius gradually changes. Also good. Further, even when the radius of curvature changes in the cross-sectional shape of the lens outer peripheral end face 34, it is preferable that the radius of curvature of all the curves is set within the above range.

  Then, an end portion on the lens front surface side of the lens outer peripheral end surface 34 and an end portion on the outer peripheral side of the lens front surface 24 are connected by a front side connection portion 36. In the present embodiment, the front connection portion 36 is a continuous surface in which the lens outer peripheral end surface 34 and the lens front surface 24 are smoothly connected with a common tangent line. However, for example, the surfaces on both sides may be connected with a rounded surface having a small radius of curvature in a suitable chamfered shape, or may be connected with a bent point shape having a corner in the radial cross section.

  On the other hand, the lens outer peripheral end surface 34 and the lens rear surface 26 are smoothly connected over the entire periphery of the lens outer peripheral end surface 34 at the rear side connection portion 38, which is a connection portion between the lens rear surface side and the lens rear surface 26. It is connected with a corner portion without being formed, and is a corner portion having an obtuse cross-sectional shape. The rear connection portion 38 is set within an angle α between 120 ° to 150 ° between the tangent line 11 of the lens rear surface 26 and the tangent line 12 of the lens outer peripheral end surface 34 in the present embodiment. , Approximately 135 °. Further, the rear side connecting portion 38 is separated from the outermost peripheral end of the lens in the lens radial direction (perpendicular to the optical axis, the left-right direction in FIG. 1) inward of the lens: x is 0 <x ≦ 0. It is formed at a position of 1 mm.

  In the contact lens 10 having such a structure, the lens rear surface 26 of the peripheral portion 20 is brought close to the cornea substantially at the top of the annular convex portion 28 in the mounted state, and the outer peripheral side of the adjacent portion. The annular lift part 30 is spaced apart from the cornea with a cantilevered support form at a proximal portion in the radial cross section, and opens toward the outer peripheral side with a predetermined lift amount: h at the outer peripheral edge part of the contact lens 10. An annular gap 40 will be formed.

  In addition, when the contact lens 10 is mounted, the vertical lower portion of the outer peripheral edge of the contact lens 10 in a front view (as viewed from the optical axis direction) is positioned so as to be substantially in contact with or close to the lower eyelid due to the action of gravity. It will be.

  Therefore, in the contact lens 10 at the time of wearing, tears present on the cornea can be introduced into and retained in the annular gap 40 by the action of surface tension, and are particularly drawn from above the lower eyelid where there is a lot of tears. As a result, tears are introduced into the entire outer circumference of the contact lens 10 along the annular gap 40.

  Under such conditions, when the wearer blinks, the upper eyelid rides on the peripheral portion 20 of the contact lens 10 and the optical unit 18 to exert a pressing force, and then quickly escapes and the pressing force is released. Become. The optical portion 18 and the peripheral portion 20 of the contact lens 10 are elastically deformed by the action of the pressing force, and the tear film formed between the optical portion 18 and the cornea, the peripheral portion 20 and the eyeball. The volume of the annular gap 40 in which tears are held between the surfaces is positively changed. As a result, a pumping action that positively draws in and out the tear fluid is exerted between the tear fluid layer and the annular gap 40, so that the tear fluid between the optical unit 18 and the cornea is efficiently exchanged. It can be done.

  Here, in particular, the contact lens 10 having the structure as described above has a corner having a specific structure in the connection portion 38 between the lens inner surface (lens rear surface) 26 and the outer peripheral end surface 34 with respect to the shape of the edge portion. . That is, the contact lens 10 has a clear structural difference from the round edge structure in which the inner and outer surfaces of the lens are connected without having corners with respect to the outer peripheral end surface in that the connecting portion 38 has corners. There is. Further, the contact lens 10 has a connecting portion 38 positioned at a connecting portion between the lens rear surface 26 and the outer peripheral end surface 34, and the outer peripheral end surface 34 rising from the connecting portion 38 has a smooth convex curved surface shape. Accordingly, the lens is positioned at a specific distance: x (0 <x ≦ 0.1 mm) radially inward from the outermost peripheral end of the lens, and the angle of the connection portion 38 is further set to a specific angle: α. In terms of (120 degrees ≦ α ≦ 150 degrees), for example, there is a clear structural difference from the sharp edge structure as shown in FIGS.

  Thus, on the basis of such structural features, in the contact lens 10, while avoiding inconveniences in the sharp edge structure (decrease in wearing feeling due to stimulation, bulbar conjunctival epithelial disorder and a feeling of dryness, etc.) Even aspherical contact lenses have a novel edge structure that can advantageously ensure positional stability during wearing, especially when compared to conventional round edge structures. Stability can be greatly improved.

Further, in the contact lens 10 having the above-described structure, since the rear connection portion 38 that is a connection portion between the lens outer peripheral end surface 34 and the lens rear surface 26 in the edge portion 22 is a corner portion (obtuse angle), Excess penetration of tears can be suppressed by causing the rear connection portion 38 to approach or contact the specific position of the conjunctiva. At the same time, the support by the three points of the lens center portion and both edge portions in the longitudinal section is more stably performed by the positioning action such as the catch on the bulbar conjunctiva. In addition, since the rear connection portion 38 is positioned sufficiently close to the outer peripheral edge, the area of the proximity or contact between the lens rear surface 26 of the peripheral portion 20 and the conjunctiva is close to the lens outer diameter. Greatly secured. Therefore, the relative displacement resistance force (for example, frictional resistance force) between the contact surface and the contact surface between the rear surface of the lens and the eyeball surface in the wearing state is increased, so that the lens shape is not adjusted to the eyeball surface. Excellent positional stability can be obtained immediately after wearing.

  Thereby, in the contact lens 10 having the structure according to the present embodiment, the use of the highly water-containing material and the advantage of using the inner aspherical shape, oxygen supply to the cornea by tear fluid permeation and exchange, Excellent positional stability can be effectively ensured immediately after wearing, while ensuring the effects of reducing the feeling of foreign matter and improving the feeling of wearing by improving the familiarity with the eyeball surface.

  In manufacturing such a contact lens, first, as shown in FIG. 4, a mold die 52 that defines a molding cavity 50 corresponding to the shape of the target contact lens 10 is prepared. The mold 52 has a split mold structure composed of an upper mold 54 and a lower mold 56. By being mold-matched with each other, the mold-matching surfaces of the lower and upper molds 54, 56 are separated. A molding cavity 50 is formed on the substrate.

  Here, the molding surface 58 as the cavity forming surface of the upper mold 54 is substantially the same shape as the entire lens rear surface including the rear optical portion 16 of the target contact lens 10 and the lens rear surface 26 in the peripheral portion 20. It is formed with.

  On the other hand, as shown in FIG. 5, the molding surface 60 as the cavity forming surface of the lower mold 56 has an outer peripheral portion 62 that is substantially the same as the lens front surface 24 in the peripheral portion 20 of the target contact lens 10. The outer peripheral edge portion 64 of the outer peripheral portion 62 is formed with the same shape as that of the edge portion 22 of the contact lens 10. Then, the upper mold 54 is overlaid on the outer peripheral edge 64 of the lower mold 56, thereby forming a corner 66 having substantially the same shape as the rear connection part 38 of the contact lens 10. It is like that. Further, the central portion 68 of the molding surface 60 is formed by removing the front optical portion 14 of the contact lens 10 from its center of curvature so that a lens central portion thicker than the optical portion 18 of the target contact lens 10 is molded. The shape is such that it is substantially offset in the direction.

  It should be noted that the optical portion 18 of the target contact lens 10 to be considered when setting the shape of the central portion 68 of the molding surface 60 includes all the contact lenses 10 having various lens powers constituting a series type contact lens. Among these, it is preferable that the contact lens has the thickest optical part 18. In this way, the mold 52 can be used for molding all contact lenses 10 having various lens powers constituting a series contact lens.

  When the contact lens 10 is molded using such a mold 52, the molding surface 60 of the lower mold 56 that is opened is opened upward, and a monomer material for molding the contact lens is formed there. Inject a predetermined amount. Subsequently, the upper mold 54 is superposed from above the lower mold 56, and the monomer material is filled into the molding cavity 50 defined between the lower and upper molds 56,54. Thereafter, the monomer material is subjected to an appropriate treatment such as ultraviolet irradiation or heating to accelerate the polymerization, thereby molding the contact lens body.

  The contact lens body thus obtained has the entire rear surface of the lens in the shape of the target contact lens 10, and the lens front surface also has the target contact lens 10 in the peripheral portion 20. It is made into a shape. That is, the contact lens body is substantially molded with the shape of the target contact lens 10 except for the front optical unit 14.

  And the target contact lens 10 will be completed by cutting only the front surface optical part 14 with respect to the obtained contact lens element | base_body. The cutting process is performed, for example, by holding the lower molding die 56 on the chuck of the cutting apparatus while the contact lens body is still attached to the lower molding die 56. It can be advantageously carried out by turning the body around the central axis of the lens and cutting with a suitable cutting tool.

  According to such a manufacturing method, the entire surface excluding the front optical unit 14 can be molded with the mold 52 having a substantially single shape, and then the cutting process performed on the front optical unit 14 is performed. By simply adjusting the amount, series contact lenses can be manufactured very efficiently.

  Moreover, it is possible to manufacture the contact lens 10 by using not only single-sided molding as described above but also double-sided molding. In such a case, the lower surface is provided with a molding surface 60 having substantially the same shape as the entire lens front surface including the front optical part 14 of the contact lens 10 of various lens powers constituting the series type contact lens. A side mold 56 is prepared, and a mold mold 52 having a molding cavity having a shape substantially the same as the whole including the front optical part 14 of the target contact lens 10 is prepared. Then, similarly to the above-described single-sided molding, the target contact lens can be obtained by filling the molding cavities of the lower and upper molding dies 56 and 54 with a monomer material to promote polymerization. In this way, the target contact lens can be obtained directly by molding, and the cutting process can be omitted.

In addition, with regard to a large number of contact lenses manufactured with various edge radii, lens size change rates, and edge lift sizes, it is targeted for more than 50 monitors who have no eye disease and have experience wearing contact lenses. More than 100 eyes were evaluated using lenses with eye fitness. In the following evaluation, wearing feeling, lens movement amount, and visibility stability were set as evaluation items. The wearing feeling was evaluated based on four levels of “good”, “substantially good”, “slightly bad”, and “bad” by interrogating foreign body feeling, irritation and the like. The lens movement amount was determined by measuring the lens movement amount during wearing, and setting the movement amount of 0.2 to 0.6 mm as “good”. In addition, the visual stability is questioned about the visual stability during wearing,
The evaluation was made in four levels: “good”, “substantially good”, “slightly bad”, and “bad”. Since the evaluations performed are enormous, the formation of individual evaluation data is omitted here, and the results of statistical processing of a large number of obtained evaluation data are shown in the following tables.

  Table 1 shows the results of an experiment for confirming the influence of the curvature radius r of the edge on the wearing feeling. As is clear from Table 1, it was confirmed that a good wearing feeling can be obtained within the range of 0.03 mm ≦ r ≦ 0.05 mm which is the structure according to the present invention. As a result, the radius of curvature of the edge leads to the thickness of the lens. Therefore, when r <0.03 mm, it becomes sharp and irritate, while when 0.05 mm <r, the thickness is felt. It is presumed to be caused by

  Table 2 shows the angle between the tangent to the rear surface of the lens and the tangent to the outer peripheral edge of the corner: Results of experiments confirming the effect of α on wear, lens movement, visual stability, bulbar conjunctival epithelial disorder, and dryness Indicates. As a lens in this experiment, a lens having an edge radius: r = 0.04 mm was used. As is apparent from Table 2, it is possible to obtain a good wearing feeling, a lens movement amount, and a visual stability within the range of 120 ° ≦ α ≦ 150 °, which is a structure according to the present invention, and the conjunctival epithelium. It was confirmed that there was no problem with the trouble or dryness. This result shows that when α <120 °, the corners are sharp and give a stimulus, whereas when 150 ° <α, the corners are substantially not formed, which is large compared to the conventional structure. This is presumed to be due to the absence of the difference.

  Table 3 shows three types of contact lenses (α = 120 degrees, 135 degrees, 150 degrees) as examples according to the present invention based on the experimental results shown in Table 2, and comparative examples. 1 as a representative example of a sharp edge structure (with δ1 = 90 degrees in FIG. 10 (α = 90 degrees in Table 2)), and a kind of a round edge structure as a comparative example (a section having a spherical convex curved surface) The results are shown by comparing the overall ratings with respect to the outer peripheral end surfaces connected to the inner and outer surfaces of the lens with a common tangent line (α = 180 degrees in Table 2). From the overall review of Table 3, the edge part structure according to the present invention is capable of exhibiting a novel structure different from both the sharp edge structure and the round edge structure and a novel function and effect based thereon. It is understood.

  Table 4 shows the result of an experiment for confirming the influence of the lens size change rate: ΔD on the wearing feeling, the lens movement amount, and the visibility stability. The lens used in this experiment was an edge radius: r = 0.04 mm, and an angle formed by a tangent to the rear surface of the lens and a tangent to the outer peripheral end surface of the lens: α = 135 °. As is clear from Table 4, it was confirmed that good wearing feeling, lens movement amount, and visibility stability can be obtained within the range of 1% ≦ ΔD <5%, which is the structure according to the present invention. Such a result is presumed to be caused by the fact that the lens shape is not sufficiently adapted to the cornea if the rate of change is too small.

  Table 5 shows the results of an experiment for confirming the effect of edge lift: h on wearing feeling, lens movement amount, and visibility stability. The lens used in this experiment was an edge radius: r = 0.04 mm, and an angle formed by a tangent to the rear surface of the lens and a tangent to the outer peripheral end surface of the lens: α = 135 °. As is apparent from Table 5, it was confirmed that good wearing feeling, lens movement amount, and visibility stability can be obtained within a range of 0.04 mm ≦ h ≦ 0.12 mm, which is a structure according to the present invention. . As a result, when h <0.04 mm, the corner portion is formed, which causes irritation. On the other hand, when 0.12 mm <h, it is too far from the cornea and the positioning effect is not effectively exhibited. It is presumed to be caused.

  As mentioned above, although one embodiment of the present invention has been described in detail, this is merely an example, and the present invention is not construed as being limited in any way by the specific description in the embodiment. The present invention can be implemented in a mode in which various changes, corrections, improvements, and the like are added based on the knowledge of a trader, and such a mode is within the scope of the present invention as long as it does not depart from the spirit of the present invention. Needless to say, it is included in.

  For example, FIG. 6 shows a contact lens 80 as a second embodiment of the present invention. Note that the contact lenses 80 and 90 according to the embodiments of the present invention described below are both soft type contacts made of a highly hydrous soft material, like the contact lens 10 of the first embodiment. Since they are lenses, members and parts having the same structure as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment in the drawings, and detailed descriptions thereof are given. Is omitted. Further, the contact lens 80 as the second embodiment described below exemplifies a configuration in which the shape of the edge portion 22 is different from that of the contact lens 10 of the first embodiment. Only an explanatory view of an enlarged vertical section corresponding to FIG. 3 is shown in FIG.

  That is, the longitudinal cross-sectional shape of the lens outer peripheral end surface 34 is a curved shape in which the curvature gradually changes from the lens front surface 24 to the lens rear surface 26 as in the contact lens 80 as the second embodiment shown in FIG. It may be equal. Thus, the longitudinal cross-sectional shape of the lens outer peripheral end face 34 is not necessarily limited to the arc shape or the combination thereof as in the first embodiment described above, Various shapes such as a shape represented by a conical curved surface and a shape represented by a trigonometric function can be appropriately employed.

  Furthermore, in any of the above-described embodiments, the lens rear surface 26 in the peripheral portion 20 is a curved surface that is concave in the lens radial direction cross section and is slightly curved in front of the lens. Further, at least a part of the lens rear surface 26 may be formed into a linear shape in the lens radial direction cross section. As such a mode, for example, FIG. 7 shows a contact lens 90 as a third embodiment. An annular connecting portion 92 is formed over the entire circumference of the contact lens 90 at a radially intermediate portion of the inner surface of the peripheral portion 20 in the contact lens 90. Then, on the inner side in the lens radial direction across the annular connecting portion 92, a curved surface 94 having a concave surface in the lens radial direction and slightly convex in front of the lens is formed on the entire circumference of the peripheral portion 20. It is spread and formed. On the other hand, on the outer side in the lens radial direction across the annular connecting portion 92, the lens radial cross section is linear, and a tapered surface 96 that is inclined with respect to the lens central axis 12 extends over the entire circumference of the peripheral portion 20. Is formed. The curved surface 94 and the tapered surface 96 are connected by the annular connecting portion 92, whereby the lens rear surface 26 as the inner surface of the peripheral portion 20 is configured. In such a contact lens 90, as shown in FIG. 8, the obtuse angle: α ″ of the rear connection portion 38 as a corner is a straight line: l1 ′ constituting the tapered surface 96 and a tangent line of the lens outer peripheral end surface 34: It is determined by the angle formed by l2.

  Furthermore, the shape in which at least a part of the lens rear surface 26 is a straight line in the lens radial direction cross section is not limited to the shape as in the third embodiment. For example, a straight line and a curved line may be alternately formed in the lens radial direction in the lens radial cross section to form a plurality of tapered surfaces in the lens radial direction, or the entire lens rear surface 26 may be formed in the lens radial direction. Various shapes such as a tapered surface that is straight in the cross section or a plurality of tapered surfaces having different inclination angles at different positions in the lens radial direction can be appropriately employed.

  In addition, although not listed one by one, the present invention can be implemented in a mode with various changes, modifications, improvements, and the like based on the knowledge of those skilled in the art. It goes without saying that all are included in the scope of the present invention without departing from the spirit of the invention.

Claims (7)

In a soft contact lens formed from a hydrous material, an optical part is provided in the center part of the lens, and a peripheral part is provided on the outer peripheral side of the optical part.
While at least one of the inner surface of the optical part and the inner surface of the peripheral part is aspherical, the inner surface of the peripheral part gradually increases from the extension line of the inner surface of the optical part as it goes outward in the lens radial direction. A separate edge lift is set, and the outer peripheral end surface of the lens is convex toward the outer peripheral side and has a smoothly continuous curved cross-sectional shape without corners, and the outer peripheral end surface of the lens and the center of curvature are the lens. The connecting portion with the inner surface of the peripheral portion set at the rear has a cross-sectional shape of obtuse angle: α positioned at a distance: x away from the outermost peripheral end of the lens inwardly in the lens radial direction. The separation distance: x is 0 mm <x ≦ 0.1 mm and the obtuse angle: α is 120 degrees ≦ α ≦ 150 degrees , and the outer peripheral end surface of the lens extends over the whole. Radius of curvature: r is 0.0 Soft contact lenses, characterized in that it has a mm ≦ r ≦ 0.05 mm and cross-section shape.   The inner surface of the peripheral portion is a concave curve line in the lens radial direction cross section, and the obtuse angle: α is determined by an angle formed by a tangent line of the curve line and a tangent line of the lens outer peripheral end surface in the connection portion. The soft contact lens according to claim 1.   While the inner surface of the optical part is aspherical, at least a part of the inner surface of the peripheral part is a straight line in the cross section in the lens radial direction. The soft contact lens according to claim 1, wherein the obtuse angle: α is determined by an angle formed by. The radius of curvature of the lens outer peripheral edge surface: r is, is constant throughout its soft according to any one of claims 1 to 3 cross-sectional shape of the lens outer peripheral end surface is an arcuate shape contact lens. The soft contact lens according to any one of claims 1 to 4 , wherein a size of the edge lift: h is 0.04 mm ≤ h ≤ 0.12 mm. Lens size in the swollen state in 20 ° C. physiological saline: D ₂₀ to lens size in the swollen state in 35 ° C. saline: D ₃₅ Rate of change: ΔD
ΔD = (D ₂₀ −D ₃₅ ) / D ₂₀ × 100 (%)
It said change rate when expressed in the soft contact lens according to any one of claims 1 to 5 which is 1% ≦ ΔD ≦ 5%. The inner surface of the optical part has an aspherical surface formed by an elliptical surface having an eccentricity within a range of 0.2 to 0.7 and a vertex radius of curvature of 5.00 mm to 10.00 mm. The soft contact lens according to any one of claims 1 to 6 .

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