WO2007066666A1

WO2007066666A1 - Soft contact lens

Info

Publication number: WO2007066666A1
Application number: PCT/JP2006/324281
Authority: WO
Inventors: Yukihisa Sakai; Katsunori Yamada; Yuji Goto; Hiroaki Suzuki
Original assignee: Menicon Co., Ltd.
Priority date: 2005-12-05
Filing date: 2006-12-05
Publication date: 2007-06-14

Abstract

A soft contact lens of a novel structure which can attain positional stability of the contact lens by limiting the movement of the lens to within an appropriate range when it is worn without sacrifice in excellent feeling of wearing of a contact lens having an aspherical inner surface profile close to the profile of cornea. Outer circumferential end face (34) of the lens has a cross-section of curved surface projecting toward the outer circumferential side, and the joint (38) of the outer circumferential end face (34) of the lens with the inner surface (26) at the peripheral portion (20) is a corner portion having a cross-section profile of obtuse angle: α and spaced apart radially inward by a distance: x from the outermost circumferential end of the lens, where 0<x≤0.1 mm and 120°≤α≤150°.

Description

Specification

Soft contact lenses technical field

[0001] The present invention relates to a technique for maintaining good wearing comfort and positional stability of soft contact lenses, and is particularly advantageously applied to soft contact lenses that are also formed with water-containing material strength. .

Background technology

[0002] Contact lenses are required not only to have optical properties to exhibit the intended vision correction function, but also to have a good feeling of wearing without giving a foreign body sensation when worn. From this point of view, the inner surface of a contact lens that overlaps the cornea and bulbar conjunctiva is generally a concave spherical surface, taking into account the spherical ocular surface.

[0003] Incidentally, it is known that the shape of the human cornea is not a precise spherical surface, but an aspherical surface whose curvature decreases from the center toward the periphery. Therefore, a number of contact lenses have been proposed in the past, in which the optical part has an aspherical concave inner surface shape that is closer to the corneal shape than a concave spherical surface. For example, those described in Japanese Patent Publication No. 49-18266, Japanese Patent Publication No. 62-502830, US Pat. No. 4,765,728, etc. In addition, the present applicant previously proposed a soft contact lens having an inner surface shape that more closely approximates the corneal shape in Patent Document 1 (Japanese Patent Application Laid-Open No. 6-194609).

[0004] A contact lens having such an aspherical inner surface shape can be worn with its inner surface aligned more closely with the eyeball surface than a contact lens having a spherical inner surface shape. Therefore, not only the wearing comfort is improved, but also the adverse effects of the lacrimal lens can be suppressed and the optical properties can be improved.

[0005] However, after many experiments and studies by the present inventor, it was found that contact lenses in which the inner surface of the optical part is aspherical have problems with the stability of the position on the eyeball surface. It turns out that there are cases where it is possible to survive.

[0006] Specifically, contact lenses that have an aspherical inner surface shape that approximates the corneal shape may cause eyeball damage in certain cases, such as when the spherical lens power is particularly large or immediately after wearing. It was confirmed that the lens position on the surface tends to be difficult to stabilize. Furthermore, this tendency was confirmed to be particularly pronounced in soft contact lenses made of materials with high water content.

[0007] Therefore, the lack of positional stability of contact lenses on the eyeball surface during wear, which is a problem newly discovered by the present inventors, has a negative impact on vision and wearing comfort. Since there is a risk of this happening, some kind of countermeasure is required.

[0008] The cause of the instability of the contact lens position as described above has not yet been fully elucidated, but as a result of the inner surface shape of the contact lens becoming more similar to the eyeball surface shape, the conventional concavity The positioning effect that occurs with spherical contact lenses, such as the hooking force caused by strong contact with a specific position on the eyeball surface, is no longer exerted, and the entire inner surface of the contact lens is placed on the eyeball surface. It is presumed that one of the reasons is that as a result of smooth contact with the eyeball, it becomes easier to slide on the eyeball surface. In addition, with thick contact lenses, the effect of gravity is thought to be involved. Furthermore, contact lenses with high water content are thought to be affected by changes in shape due to temperature changes, especially when the temperature rises to the body temperature immediately after wearing. It is assumed that one of the causes of instability in the lens position is that the distance between the surface forces increases and the lachrymal fluid circulates too much.

[0009] By the way, in order to deal with the problem of instability of the lens position, it is conceivable to adopt a sharp edge structure in which a corner is formed at the outermost peripheral end of the edge portion of the contact lens. This sharp edge structure can be realized, for example, by making the rising part 4 of the outer peripheral edge force of the inner surface of the lens at the edge part of the contact lens 2 have an acute-angled cross section with an angle of δ 1, as shown in Fig. 9, but there are other methods, such as As shown in Fig. 10, the inner surface force of the contact lens 6 can also be realized by forming an angle 8 of angle δ 2 on the outer peripheral end surface of the lens raised to a predetermined height (Patent Document 2 (Japanese Unexamined Patent Publication No. 57-181525) (Refer to Publication No.)). In FIGS. 9 and 10, A and B represent tangents to the inner and outer surfaces of the lens at the edge portion.

[0010] The inventor of the present application has investigated the problem and found that if a sharp edge structure is adopted in which the rising part of the inner surface of the lens at the edge part is made into an acute-angled cross section or a corner is formed on the outer peripheral end surface of the lens, the contact Lens positional stability when wearing lenses Although improvements are being made, the angles at the edges not only reduce the comfort of wearing, such as increased discomfort due to irritation, but also cause bulbar conjunctival epithelial damage and a feeling of dryness. But it clearly became a force. Therefore, the sharp edge structure is an effective solution for improving the positional instability of contact lenses with an aspherical inner surface shape as described above.

[0011] However, if a round edge structure with no corners and a smoothly continuous curved cross-sectional shape is adopted at the edge of a contact lens, problems such as a decrease in wearing comfort due to such a sharp edge structure may occur. do not. However, it goes without saying that the round edge structure cannot provide any solution to the problem of positional instability during wearing in a contact lens having an aspherical inner surface shape as described above.

[0012] Patent Document 1: Japanese Unexamined Patent Publication No. 6-194609

Patent document 2: Japanese Patent Application Laid-open No. 181525

Disclosure of invention

Problems that the invention seeks to solve

[0013] Here, the present invention was made against the background of the above-mentioned circumstances, and the problem to be solved is to provide a contact lens having an aspherical inner surface shape close to the shape of the cornea. The lens can be moved within an appropriate range during wear without causing problems such as poor wearing comfort, bulbar conjunctival epithelial damage, and dryness caused by irritation at the corners, as would be the case when a sharp edge structure is used. It is an object of the present invention to provide a contact lens with a novel structure, which can achieve positional stability of the contact lens by limiting the inner surface of the lens, together with excellent wearing comfort exhibited by the aspherical inner surface shape.

Means to solve problems

[0014] Hereinafter, embodiments of the present invention that have been made to solve the above-mentioned problems will be described. Note that the constituent elements employed in each aspect described below can be employed in any possible combination. In addition, the aspects or technical features of the present invention are not limited to those described below, but are based on the description of the entire specification and drawings, or the inventive idea that can be understood by a person skilled in the art from those descriptions. It should be understood that this is something that is recognized as such. [0015] That is, a feature of the present invention is that the lens is made of a water-containing material, has an optical part in the central part of the lens, and has a peripheral part on the outer circumferential side of the optical part. In the contact lens, at least one of the inner surface of the optical portion and the inner surface of the peripheral portion is aspherical, and the inner surface of the peripheral portion has a shape of the optical portion as it goes outward in the radial direction of the lens. The force on the extension line of the inner surface is set with edge lifts that gradually separate from each other, and the lens outer peripheral end face is convex toward the outer peripheral side and has a smoothly continuous curved cross-sectional shape with no corners, and the lens An obtuse angle having a cross-sectional shape of OC, where the connection between the outer peripheral end face and the inner surface of the peripheral part is located at a distance: X inward in the lens radial direction from the outermost peripheral end of the lens. The reason is that the separation distance:

[0016] 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 that is closer to the corneal surface shape than a concave spherical surface. The lens shape can be made to conform to the corneal shape, providing excellent wearing comfort.

[0017] In addition, in the soft contact lens of the present invention, the connecting portion between the outer circumferential end surface of the lens and the inner surface of the peripheral portion on the inner surface of the lens has an obtuse angle shape and is close to or in contact with the bulbar conjunctiva. Even immediately after wearing, before it has absorbed into the surface, it can prevent excessive inflow of tear fluid between the inner surface of the lens and the surface of the eyeball. This makes it possible to suppress the amount of movement of the lens within an appropriate range and improve positional stability. Furthermore, since the connection between the inner peripheral surface of the lens and the outer peripheral end surface is square, the inner peripheral surface of the lens is sufficiently close to the eyeball surface in a wide area up to the square connection. are brought into contact position. These actions work together, namely, the positioning effect of the inner surface of the lens in proximity to or contact with the eyeball surface, and the area in which the peripheral inner surface approaches or contacts the eyeball surface, increasing the contact between the eyeball surface and the lens. Positional stability when wearing contact lenses can also be improved by increasing relative displacement resistance such as frictional resistance.

[0018] In particular, the separation distance in the lens radial direction between the square-shaped connection portion and the outermost peripheral end of the lens: Since the corner is formed close to the outermost edge of the lens where the force is 0< I can do it. In addition, when viewed from the front in the axial direction, the square-shaped connection part enters inward from the outermost edge of the lens and is hidden so that it is covered, which may cause the connection part to unnecessarily catch on the bulbar conjunctiva. is prevented. Furthermore, since the angular connection part has an obtuse angle: α of 120 degrees ≤ α ≤ 150 degrees, excessive tension of the forceful connection part on the bulbar conjunctiva can be avoided. In addition, the corners formed near the outermost edge of the inner surface of the lens can prevent unnecessary intrusion of lachrymal fluid.

[0019] Note that the corner in this embodiment refers to a corner in which the outer circumferential end surface of the lens and the inner surface of the peripheral part are connected at an obtuse angle without having a common tangent line, forming a clear line in shape. That's fine. For example, in the longitudinal section of the lens, the surfaces extending on both sides of the connecting portion to form corners do not need to be straight lines, but one or both may be curved lines.

[0020] 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 whose longitudinal cross-sectional shape is expressed by an appropriate multidimensional equation, or an ellipsoidal surface having a predetermined eccentricity. It may also be a conical surface such as. In addition, it is not necessary that the entire inner surface has a constant shape; for example, a portion of the inner surface of the peripheral portion may have a vertical cross-sectional shape that is straight, concave or convex with a force directed toward the rear of the lens, or uneven. It may also be a shaped curved surface. Furthermore, for example, an aspherical surface can be formed by dividing the optical part into a central part and a peripheral part, and forming the central part and peripheral parts with ellipsoidal surfaces or the like having mutually different eccentricities. Also good. Further, in addition to the rotating body shape, the inner surface of the optical part and the peripheral part may be formed with a non-rotating body shape, for example, provided with a prism or a cylinder.

[0021] In addition, the soft contact lens structured according to the present invention has a smoothly continuous curved cross-sectional shape on the outer circumferential end surface of the lens without any corners, so that the soft contact lens has a smooth and continuous curved cross-sectional shape without any corners. ) can further alleviate irritation. Note that such a curved cross-sectional shape may be any shape having no corners and does not necessarily have to be an arc shape with a constant curvature. It may also be a curved cross-sectional shape in which the curvature gradually changes as it goes. [0022] In particular, in the present invention, by adopting the obtuse angle a in the specific angular range as described above, very excellent effects can be obtained in terms of the feeling of wearing, the movement range of the lens, and the positional stability. I can do it. Obtuse angle of the lid and corners: If a is less than 120°, the corners become sharp and may cause more irritation to the eyes, reducing comfort. On the other hand, if the obtuse angle (α) of the corner is larger than 150°, the corner becomes close to a state where no corner is formed, and it may be difficult to obtain sufficient positional stability of the lens during the intended wearing. .

[0023] In short, in the contact lens having the structure according to the present invention, by making the lens outer peripheral end surface have a convex curved cross-sectional shape without corners, defects at the edges of the sharp edge structure as described above (due to stimulation) can be avoided. Distance in which the connecting part between the outer peripheral edge of the lens and the inner surface of the lens is separated radially inward from the outermost edge of the lens while avoiding problems such as decreased wearing comfort, bulbar conjunctival epithelial damage, and dryness (e.g., deterioration of wearing comfort, bulbar conjunctival epithelial damage, dryness, etc.): By setting Even in this case, the positional stability when worn was advantageously ensured, and in particular, the positional stability when worn was significantly improved compared to those with a round edge structure.

[0024] 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 of this curved line and the The obtuse angle (OC) is preferably determined by the angle formed by the tangent to the outer peripheral end surface of the lens. In this embodiment, the inner surface of the peripheral portion can also be made into an aspherical shape. In particular, since the inner surface of the peripheral part is shaped to be concave backward, it is possible to advantageously secure the amount of lachrymal fluid retained between the cornea and the peripheral part.

[0025] That is, in the soft contact lens having the structure according to the present invention, any of the following embodiments (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 has a shape other than an aspherical shape, such as a spherical 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) above refers to a concave spherical shape. It has a concave shape similar to the corneal surface shape.

[0026]Furthermore, in the present invention, at least one of the inner surface of the optical part and the inner surface of the peripheral part may have a relatively aspherical shape. Therefore, in the present invention, for example, while the inner surface of the optical section is aspherical, at least a part of the inner surface of the peripheral section is a straight line in the cross section in the lens radial direction, and this straight line is formed at the connecting section. A configuration in which the obtuse angle: OC is determined by the angle formed by the tangent to the outer peripheral end surface of the lens is also suitably adopted.

[0027] In short, in the present invention, the embodiment in (ii) above in which at least a part of the inner surface of the peripheral portion has a linear shape in the longitudinal section may also be adopted. In this embodiment, a portion of the inner surface of the peripheral portion may be a straight line in the longitudinal section, or the entire inner surface of the peripheral portion may be a straight line in the longitudinal section. This can facilitate the design and manufacture of the inner surface of the peripheral portion.

[0028] In the soft contact lens according to the present invention, the outer circumferential end surface of the lens has a cross-sectional shape with a radius of curvature: r of 0.03 mm ≤ r ≤ 0.05 mm. Can be adopted.

[0029] By adopting such a value of the radius of curvature: r, it is possible to obtain an even better wearing feeling when wearing the product. If the radius of curvature of the outer periphery of the lens is smaller than 0.03 mm, the outer periphery of the lens will be sharp and may irritate the eyes. On the other hand, if the radius of curvature of the outer peripheral edge is larger than 0.05 mm, the thickness of the lens may be felt, which may impair the comfort of wearing the lens. Note that the cross-sectional shape of the outer circumferential end surface of the lens in this embodiment is not limited to an arc shape having a constant radius of curvature throughout, but may have a plurality of arc shapes having different radii of curvature within the above range. It may also be a curved shape in which curves are connected continuously.

[0030] In the soft contact lens according to the present invention, it is preferable that the radius of curvature: r of the outer circumferential end surface of the lens is constant throughout, and the cross-sectional shape of the outer circumferential end surface of the lens is arc-shaped. will be adopted.

[0031] By setting such a constant radius of curvature r, the outer peripheral end face of the lens can have an even smoother surface shape. As a result, it becomes possible to more effectively suppress the contact stimulation of the outer peripheral end surface of the lens to the cornea, and to obtain excellent wearing comfort. [0032] 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 adopted.

[0033] By setting the magnitude of the edge lift as described above, it is possible to obtain even better effects in terms of the feeling of wearing the contact lens, the movement range of the lens, and the positional stability. If the size of the edge lift is smaller than 0.04 mm, there is a risk that the amount of retained tear fluid in the peripheral area will be too small and the wearing comfort will deteriorate. On the other hand, if the size of the edge lift is larger than 0.12 mm, the corner will be too far away from the bulbar conjunctiva, and the corner will have the effect of suppressing the flow of tear fluid in the direction of ingress and egress and increasing the relative displacement resistance to the ocular surface. This may make it difficult to achieve the desired effect of improving the positional stability of the contact lens.

[0034] In the soft contact lens according to the present invention, the lens size in a swollen state in 20°C physiological saline: D Ka et al. The lens size in a swollen state in 35°C physiological saline

20

rate of change to D: A D is expressed by the formula: A D= (D -D ) /D

35 20 35 20

It is desirable that the rate of change is 1% ≤ A D ≤ 5%.

[0035] Conventionally, in soft contact lenses having such a temperature-dependent shape change rate, there has been a strong possibility that the wearing comfort may deteriorate immediately after wearing. On the other hand, in the present invention, even with a soft contact lens that has a material strength that has a large rate of change in shape with temperature, such as a forceps lens, it is possible to stably obtain a good wearing feeling immediately after wearing. Therefore, a large degree of freedom in selecting the lens material can be ensured without compromising the wearing comfort. Note that if the temperature-shape change rate of the lens is greater than 5%, the shape before the lens shape changes and the shape after the change will be too different, so even when the present invention is applied, it is difficult to always maintain a good wearing comfort. It may become difficult to obtain. On the other hand, compared to the conventional structure, the effect of improving wearing comfort according to the present invention is particularly advantageous when the temperature-shape change rate of the lens is 1% or more.

[0036] In the soft contact lens according to the present invention, the inner surface of the optical part has an eccentricity within the range of 0.2 to 0.7 and a vertex radius of curvature of 5.OOmn! ~ 10. An aspheric configuration formed by an elliptical surface of 0 mm can be advantageously employed.

[0037] In a soft contact lens with an inner surface of the optical part having such an ellipsoidal force, excellent wearing comfort is achieved by making the inner surface shape of the optical part approximate the shape of the central part of the cornea. You can get it. Then, while maintaining such excellent wearing comfort, positional stability when wearing the contact lens can be advantageously ensured.

[0038] In the present invention, the inner surface of the optical section does not necessarily have to be formed into a single shaped surface. For example, even if the inner surface of the optical part is formed by an elliptical surface with the above-mentioned specific shape, only the central part of the optical part has 0.2≤eccentricity (e)≤0.7, 5.OOmm≤vertex radius of curvature (r ) ≤ 10.00mm, and the peripheral parts of this central part are formed by ellipsoidal surfaces, etc. that differ in at least one of eccentricity and vertex curvature radius, and these central parts It is also possible to form an aspherical surface on the inner surface of the optical part by combining the two ellipsoidal surfaces of the ellipsoid and the peripheral portion. In addition, when both the central part and the peripheral part of the optical part of the optical part are formed as ellipsoids, the eccentricity of not only the inner surface of the optical part but also the inner surface of the peripheral part must be set within the above range. , I like it.

Effect of the invention

[0039] As is clear from the above description, the soft contact lens having the structure according to the present invention! By configuring the connection between the outer edge of the lens and the inner surface of the periphery with a corner with a specific shape, the aspherical shape on the inner surface of the optical part and periphery of the contact lens maintains a good wearing comfort. At the same time, positional stability when wearing contact lenses can be advantageously achieved.

Brief description of the drawing

[0040] [FIG. 1] A cross-sectional view showing a contact lens as a first embodiment.

[Figure 2] Front view of the same contact lens.

[Figure 3] An enlarged cross-sectional view of the main parts of the same contact lens.

[Figure 4] Cross-sectional explanatory diagram for explaining the molding die.

[Figure 5] An enlarged cross-sectional view of the main parts of the same mold.

[Figure 6] An enlarged cross-sectional view of main parts showing a contact lens as a second embodiment.

[Figure 7] A cross-sectional view showing a contact lens as a third embodiment.

[Figure 8] An enlarged cross-sectional view of the main parts of the same contact lens.

[Figure 9] A cross-sectional explanatory diagram showing an example of a sharp edge structure of a contact lens that is not included in the present invention. [Figure 10] A cross-sectional explanatory diagram showing another example of the sharp edge structure of a contact lens, which is not included in the present invention.

Explanation of symbols

[0041] 10: Contact lens, 14: Front optical section, 16: Back optical section, 18: Optical section, 20: Peripheral section, 22: Edge section, 24: Front surface of lens, 26: Back surface of lens, 30: Annular lift section , 34: Lens outer peripheral end surface, 36: Front connection section, 38: Rear connection section

BEST MODE FOR CARRYING OUT THE INVENTION

[0042] 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.

[0043] First, FIGS. 1 and 2 show a specific structural example of a contact lens 10 as a soft contact lens structured according to the present invention. The powerful contact lens 10 has an approximately spherical shell shape with an overall dome shape, and as is well known, it is used by being worn over the surface of the eyeball, including the cornea. It has become. Note that the contact lens 10 of this embodiment has a lens center axis 12 as its optical axis, and is shaped like a body of revolution about this lens center axis 12. Therefore, in FIG. Show only the surface.

[0044] The powerful contact lens 10 is made of a highly water-containing soft material with a water content of 50% or more, thereby effectively supplying oxygen to the cornea by allowing tear fluid to pass through the lens. I can do it. Furthermore, a material having a Young's modulus of 0.5 to 2.OMPa is preferably used as a forming material for the contact lens 10, thereby achieving better wearing comfort and shape stability. At the same time, the lacrimal fluid exchange action based on surface tension and pumping action, which will be described later, can also be more advantageously exerted. As such a soft material, for example, a soft material containing hydrophilic monomers such as 2-hydroxyethyl methacrylate, methacrylic acid, pyrrolidone, N--N dimethylacrylamide, and silicone can be suitably employed.

[0045] In addition, the contact lens 10 of the present embodiment has a lens size that changes depending on temperature changes when worn, and the lens size in a swollen state in 20°C physiological saline: D

20 Force also Lens size in swollen state in saline at 35 °C: Rate of change to D: Δ ϋ =

35

(D — D ) /Ό Χ 100 (%) is set within the range of 1%≤AD≤5%. desirable. In addition, the values of lens size (D , D ) represent the lens outer diameter dimension: DIA.

20 35

[0046] More specifically, in the central portion of the contact lens 10 of this 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. These front and rear optical sections 14 and 16 form an optical zone 18 in the center of the lens, which has an appropriate lens power for vision correction. This optical section 18 has a circular shape centered on the lens central axis 12 when viewed from the front as shown in Fig. 2, and the outer diameter of the optical section 18: Taking these factors into account, the diameter is generally set at 5 to 9 mm.

[0047] In addition, the rear optical part 16 as the inner surface of the optical part 18 is arranged at the rear of the lens on the lens central axis 12 (Fig. A vertical cross section of a concave aspherical surface formed of an ellipse with the center of curvature set at the lower part of the center, preferably with an eccentricity of 0.2 to 0.7 and a radius of curvature of 5.00 to 10.00 mm. A base force with a shape is assumed to be a curved surface. As a result, when the contact lens 10 is worn, the thickness of the tear film formed between the rear optical part 16 and the surface of the cornea is kept approximately constant throughout, and the lens is formed by the tear film. The effect has been reduced or avoided!/,ru.

[0048] Note that the vertical cross-sectional shape of the base curved surface does not necessarily have to be an ellipse with a constant eccentricity over the entire inner surface of the optical part, depending on the shape of the cornea of the wearer and the wearing conditions. etc., and will be set appropriately. For example, a plurality of circular and annular regions each having a predetermined width in the radial direction may be set, and various curved shapes such as a conic curve shape having different eccentricities may be set for each region. Alternatively, the rear optical section 16 may be a spherical surface whose longitudinal cross-section is in the form of an arc with a constant curvature. Particularly in this embodiment, the rear optical section 16 has a rotating body shape with the lens center axis 12 as the center axis of rotation.

[0049] On the other hand, the front optical part 14 of the contact lens 10 is designed as a curved surface that can provide the desired lens power in cooperation with the base power curve surface 16 set as described above. In particular, in this embodiment, the center of curvature is set at the rear of the lens on the lens center axis 12, and the curved convex surface has a vertical cross-sectional shape with an appropriate radius of curvature. In addition, this The front optical part (front curve) 14 can also be shaped into an arc shape with a constant radius of curvature, or with a radius of curvature in the radial direction, taking into account the shape of the base curve surface 16, the required lens power, wearing conditions, etc. Various curved convex shapes, such as varying conic section shapes, may be employed as appropriate. The front optical section 14 in this embodiment has a rotating body shape with the lens center axis 12 as the center axis of rotation.

[0050] The optical section 18 formed by these front and rear optical sections 14 and 16 is an area that is expected to have an optical effect on the wearer's eyes, and its outer periphery, in other words, will be described later. In general, the boundary with the peripheral portion 20 can be regarded as a point of change in curvature on the longitudinal cross-section of the front surface of the lens and the rear surface of the lens, respectively. However, for example, if the lens surface of the optical part is designed to have a vertical cross-sectional shape that gradually changes in the radial direction, or if such a boundary is formed with a predetermined width in the radial direction and the optical part is closed 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, such as when it is formed by a connection area that smoothly connects the optical part 18 and the peripheral part 20.

[0051] Further, the outer circumferential portion of the contact lens 10 is provided with a peripheral portion surrounding the optical portion 18.

(peripheral zone) 20 and edge portion 22 are formed. FIG. 3 shows an enlarged cross-sectional view of the peripheral portion 20 and the edge portion 22. This peripheral part 20 has an annular shape with a predetermined width centered on the lens central axis 12 when viewed from the front as shown in FIG. 2, and the radial width dimension of the peripheral part 20: B is the optical part 18 The size and size from the outer periphery of the lens to the edge 22 of the outer periphery of the lens.

PZ

It is. The edge portion 22 connects the lens front surface 24 and the lens rear surface 26 of the peripheral portion 20.

[0052]Furthermore, the lens rear surface 26 of the peripheral portion 20 has a center of curvature set at the rear of the lens, and has an arcuate vertical cross-sectional shape with a predetermined radius of curvature. In addition, the radius of curvature: _r

P.B.

The power r ≤ 15mm also varies depending on the power (lens power) set in the optical section 18.

P.B.

It is desirable to set it to 2mm≤r ≤ 10mm. This allows wearing

P.B.

Even better wearing comfort can be achieved under certain conditions. Note that if the radius of curvature: r is too large,

P.B.

, while it becomes difficult to secure a sufficient volume of the annular gap 40 (retained tear volume), which will be described later, r force S

P.B.

If it is too small, the proximity and contact of the contact lens 10 to the ocular surface will be close to a linear state. As a result, there is a risk that the feeling of wearing the contact lens 10 will be reduced, the tear film will be disrupted, and the pumping action described below based on the deformation of the peripheral portion 20 may not be fully exerted.

[0053] Since the rear surface 26 of the lens in the peripheral portion 20 has a specific arcuate cross-sectional shape, an annular convex portion 28 that protrudes toward the cornea is formed on the rear surface 26 side of the lens. has been done. In this embodiment, the annular convex portion 28 is formed to have a substantially constant radial cross-sectional shape over the entire rear surface 26 of the peripheral portion 20 in the circumferential direction of the contact lens 10.

[0054] Furthermore, by forming the annular convex portion 28 that is convex toward the cornea side, the lens rear surface 26 of the peripheral portion 20 has an annular convex portion 28 located at the radially intermediate portion of the peripheral portion 20. Generally, the apex is closest to the cornea. Furthermore, on the outer circumferential side of the portion close to the cornea, the lens rear surface 26 of the peripheral portion 20 is positioned gradually away from the cornea as it goes radially outward. Accordingly, in the present embodiment, the annular lift portion 30, which is located opposite to the eyeball surface at a predetermined distance, can be moved in the circumferential direction by a portion of the annular convex portion 28 of the peripheral portion 20 that is on the outer circumferential side of the portion closer to the cornea. It is formed in a continuous ring shape around the entire circumference. When the contact lens 10 is worn, tear fluid is introduced and retained by the action of surface tension in the gap between the annular lift portion 30 and the opposing surfaces of the eyeball surface! /, Ru.

[0055] The amount of lift (separation distance) of the ocular surface of the annular lift portion 30 is determined by taking into account the material of the contact lens 10, the radius of curvature of the annular convex portion 28, the properties and amount of the wearer's tear fluid, etc. It should be set appropriately, but if it is too small, the amount of lachrymal fluid introduced into the gap between the opposing surfaces of the annular lift part 30 and the cornea 12 will be small, while if it is too large, the amount of tear fluid introduced into the gap between the opposing surfaces of the annular lift part 30 and the cornea 12 will decrease, while if it is too large, the amount of tear fluid introduced into the gap between the opposing surfaces of the annular lift part 30 and the cornea 12 will decrease, while if it is too large, the amount of tear fluid introduced into the gap between the opposing surfaces of the annular lift part 30 and the cornea 12 will decrease, while if it is too large, the amount of tear fluid introduced into the gap between the opposing surfaces of the annular lift part 30 and the cornea 12 will decrease. There is a risk that the contact lens 10 may come off or become significantly displaced due to contact. Therefore, in general, the forceful annular lift portion 30 extends from the rear optical portion 16 of the optical portion 18 in the contact lens 10 with a substantially constant radius of curvature (approximately the same radius of curvature as the radius of curvature of the rear optical portion 16). A contact lens with an extension line 32 extending toward the circumference and an extension line 33 extending toward the outer circumference from the lens rear surface 26 of the peripheral portion 20 with a substantially constant radius of curvature (approximately the same radius of curvature as the lens rear surface 26). Separation height of the outer peripheral edge at 10 (axial edge in the direction of the lens center axis) Lift): h-force It is desirable to set it within the range of 0.04mm to 0.12mm in the swollen state when worn. However, it is not an essential requirement for the present invention to provide such an annular lift portion 30 with an axial edge lift (h>0). For example, the edge lift may be set to 0 by forming the lens rear surface 26 of the peripheral portion 20 along the extension line 32 of the rear optical section 16, or the edge lift may be set to a negative value in consideration of the required characteristics of contact lenses. It is also possible to set it to .

[0056]Furthermore, the lens front surface 24 of the peripheral portion 20 has a center of curvature set at the rear of the lens, and has an arcuate vertical cross-sectional shape that is convex toward the front surface of the lens and has a predetermined radius of curvature. . In particular, in this embodiment, the inner peripheral edge is smoothly connected to the front optical part 14 of the optical part 18 with a common tangent, and the wall thickness of the peripheral part 20 increases as it approaches the outer peripheral edge of the peripheral part 20. The dimensions are set in consideration of the radius of curvature of the front surface of the lens in the optical section 18 and the radius of curvature of the rear surface 26 of the lens in the peripheral section 20 so that the dimensions become gradually thinner.

[0057] The front surface 24 of the lens and the rear surface 26 of the lens are connected at the edge portion 22.

The lens outer circumferential end face 34 in the force-sensitive edge portion 22 has a curved cross-sectional shape that is convex toward the outer circumferential side of the lens in a longitudinal section, and is continuous over the entire circumference of the outermost edge of the contact lens 10. It is formed by In addition, in the longitudinal section shown in FIG. 1, the lens outer peripheral end surface 34 has a smoothly continuous convex shape without any corners over the entire length from the connection point with the lens front surface 24 to the connection point with the lens rear surface 26. It is said to be the surface shape of the shape. However, the connection portion itself between the lens outer circumferential end surface 34 and the lens rear surface 26 is a rear connection portion 38 with an angle, as will be described later.

[0058] Further, the lens outer peripheral end surface 34 has a radius of curvature: r of 0.03mm≤r≤0.

It is preferable that the cross-sectional shape is 0.05 mm. This allows for better wearing comfort. In addition, particularly in this embodiment, the cross-sectional shape of the lens outer peripheral end surface 34 is an arcuate shape that is slightly smaller than the 1Z2 circumference in which the radius of curvature r is constant throughout. However, the lens outer peripheral end surface 34 does not necessarily have to be formed with a constant radius of curvature; for example, it may be formed with a plurality of curves with different radii of curvature connected continuously, or a curved cross-sectional shape with a radius of curvature that gradually changes. It's okay. Furthermore, even when the radius of curvature changes in the cross-sectional shape of the lens outer peripheral end surface 34, the radius of curvature of all curves is Preferably, it is set within a range.

[0059]The end of the lens outer peripheral end face 34 on the front side of the lens and the end of the outer peripheral side of the lens front surface 24 are connected by a front connecting part 36. In this embodiment, the front connecting 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. However, for example, the surfaces on both sides may be connected by an appropriately chamfered rounded surface having a small radius of curvature, or may be connected by a bent point shape having a corner in a radial cross section.

[0060] On the other hand, the rear connecting portion 38, which is the connection portion between the end of the lens outer circumferential end surface 34 on the lens rear surface side and the lens rear surface 26, is such that the lens outer circumferential end surface 34 and the lens rear surface 26 do not slide over the entire circumference. They are connected at the corners without being connected at any angle, and the corners have an obtuse cross-sectional shape. In the rear connecting portion 38, the angle α between the tangent line 11 of the lens rear surface 26 and the tangent line 12 of the lens outer peripheral end surface 34 is set within the range of 120° to 150°. It is said to be approximately 135°. In addition, the rear connection part 38 is separated from the outermost edge of the lens inward in the lens radial direction (horizontal direction in Figure 1, perpendicular to the optical axis): X force 0 < x≤0 . It is formed at a position that is supposed to be 1mm.

[0061] In the contact lens 10 having such a structure, when the contact lens 10 is worn, the lens rear surface 26 of the peripheral portion 20 is brought close to the cornea at approximately the top of the annular convex portion 28, and the contact lens 10 is brought close to the cornea at the approximate top of the annular convex portion 28, so that the contact lens 10 is brought close to the cornea at approximately the apex of the annular convex portion 28. The annular lift portion 30 on the outer periphery side is separated from the cornea with a cantilevered support form at a proximal portion in the radial cross section, and increases the outer periphery by a predetermined lift amount h at the outer periphery of the contact lens 10. An annular gap 40 that opens toward the side is formed.

[0062] Furthermore, when the contact lens 10 is worn, when viewed from the front (viewed from the optical axis direction), the vertical lower part of the outer peripheral edge of the contact lens 10 almost contacts or approaches the lower eyelid due to the action of gravity. It will be located at

[0063] Therefore, in the contact lens 10 when worn, tear fluid existing on the cornea can be introduced into and retained in the annular gap 40 by the effect of surface tension, especially on the lower eyelid where tear fluid is abundant. The force is also pumped up, and the tear fluid is introduced along the annular gap 40 to substantially the entire circumference of the outer circumference of the contact lens 10. [0064] Under such conditions, when the wearer blinks, the upper eyelid rides on the peripheral part 20 of the contact lens 10 and the optical part 18 and exerts a pressing force, and then quickly escapes and the pressing force is released. It will be. Then, the optical part 18 and the peripheral part 20 of the contact lens 10 are deformed due to the forceful pressing force, and the tear film formed between the optical part 18 and the cornea and the peripheral part 20 are deformed. The volume of the annular gap 40 in which tear fluid is retained between the ocular surfaces is actively changed. As a result, a pumping effect is exerted to actively move the tear fluid in and out between the tear film and the annular gap 40, so that the tear fluid between the optical part 18 and the cornea is efficiently exchanged. You get it.

[0065] Here!/, In particular, regarding the contact lens 10 having the structure as described above!/, regarding the shape of its edge portion, the inner surface of the lens (rear surface of the lens) 26 and the outer peripheral end surface 34 It has a corner of a specific structure at the connection part 38 with the . In other words, the contact lens 10 has a clear structural difference in that the connecting portion 38 has a corner, which is different from the round edge structure in which the inner and outer surfaces of the lens are connected to the outer peripheral end surface without having a corner. There is a difference. In addition, the contact lens 10 has a connecting portion 38 located at the 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. The outermost edge force of the lens is positioned radially inward by a specific distance: x (0< : oc (120 degrees ≤ α ≤ 150 degrees), there is a clear structural difference from, for example, the sharp edge structure shown in Figures 9 and 10 above.

[0066] Based on these structural features, the contact lens 10 avoids problems associated with the sharp edge structure (decreased wearing comfort due to irritation, bulbar conjunctival epithelial damage, dry feeling, etc.). In addition, it has a novel edge structure that can advantageously ensure positional stability when wearing an aspherical contact lens, especially compared to the conventional round edge structure. This greatly improves positional stability when worn.

[0067] Further, in the contact lens 10 having the above-described structure, the rear connecting portion 38, which is the connecting portion between the lens outer peripheral end surface 34 and the lens rear surface 26 at the edge portion 22, is a corner portion.

(obtuse angle), the posterior connection part 38 is close to the specific position of the bulbar conjunctiva. can prevent excessive intrusion of lachrymal fluid by contacting the At the same time, the positioning action, such as the hooking force on the bulbar conjunctiva, provides more stable support at the three points of the lens center and both edges in the longitudinal section. Furthermore, by positioning the rear connecting portion 38 sufficiently close to the outer peripheral edge, the area of proximity or contact between the lens rear surface 26 of the peripheral portion 20 and the bulbar conjunctiva is an area close to the outer diameter of the lens. A large amount will be secured. Therefore, when the lens is worn, the relative resistance to displacement (e.g., frictional resistance) between the surfaces of proximity or contact between the rear surface of the lens and the ocular surface increases, and the lens shape adapts to the ocular surface. Excellent positional stability can be obtained immediately after the previous wearing.

[0068] As a result, in the contact lens 10 having the structure according to the present embodiment, the use of a highly water-containing material and the use of an aspherical inner surface reduce the impact on the cornea due to tear permeation and exchange. Excellent positional stability can be effectively ensured immediately after wearing, while maintaining sufficient effects such as reducing the foreign body sensation due to oxygen supplementation and improving conformity to the ocular surface, and improving wearing comfort.

[0069] When manufacturing such a contact lens, first, as shown in FIG. 4, a mold 52 defining a molding cavity 50 corresponding to the shape of the desired contact lens 10 is prepared. prepare. This molding die 52 has a split mold structure consisting of an upper molding die 54 and a lower molding die 56, and when the molds are matched with each other, the mating surfaces of the upper and lower molding molds 54 and 56 are formed. A molded cavity 50 is formed between them.

[0070] Here, the molding surface 58 as the cavity forming surface of the upper mold 54 is substantially the entire rear surface of the lens including the rear optical section 16 of the target contact lens 10 and the lens rear surface 26 in the peripheral portion 20. They are formed with the same shape.

[0071] On the other hand, as shown in FIG. 5, the molding surface 60 serving as the cavity forming surface of the lower mold 56 has an outer circumferential portion 62 that is 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 to have substantially the same shape as the edge portion 22 of the contact lens 10. Then, by overlapping the upper mold 54 on the outer peripheral edge 64 of the lower mold 56, a corner 66 having substantially the same shape as the rear connecting portion 38 of the contact lens 10 is formed. It has become so. Furthermore, the central portion 68 of the molding surface 60 is The front optical part 14 of the contact lens 10 is shaped so that its central force of curvature is also substantially offset outward so that the central part of the lens is thicker than the optical part 18 of the contact lens 10. .

[0072] The optical part 18 of the contact lens 10, which is a purpose to be considered when setting the shape of the central part 68 of the molding surface 60, is a lens with various lens powers that make up the series contact lens. Among the contact lenses 10, the contact lens preferably has the thickest optical part 18. In this way, the powerful molding die 52 can be used for molding all contact lenses 10 with various lens powers constituting a series type contact lens.

[0073] When molding a contact lens 10 using such a molding die 52, the molding surface 60 of the open lower molding die 56 is forced upwardly to open, and a contact lens molding member is placed therein. A predetermined amount of monomer material is injected. Subsequently, the upper mold 54 is stacked on top of the lower mold 56, and the mold cavity 50 defined between the lower and upper molds 56, 54 is filled with the monomer material. Thereafter, the monomer material is subjected to appropriate treatments such as ultraviolet irradiation and heating to accelerate polymerization, thereby molding the contact lens body.

[0074] In the contact lens body thus obtained, the entire rear surface of the lens has the shape of the desired contact lens 10, and the front surface of the lens also has the shape of the desired contact lens 10 in the peripheral region 20. It is said to be in the shape of a contact lens. That is, substantially the entire contact lens body except for the front optical part 14 is molded into the shape of the intended contact lens 10.

[0075] Then, by cutting only the front optical part 14 of the obtained contact lens body, the desired contact lens 10 is completed. Note that such cutting can be carried out, for example, by gripping the lower mold 56 with the chuck of the cutting device while the contact lens element remains attached to the lower mold 56. This can be advantageously carried out by rotating the lens body around the lens center axis and cutting it with a suitable cutting tool.

[0076] If such a manufacturing method is followed, the entire body except for the front optical section 14 can be formed into a substantially single shape. It is possible to perform molding using a mold 52 that has been prepared, and then by simply adjusting the amount of cutting performed on the front optical part 14, it is possible to manufacture series-type contact lenses extremely efficiently. It will become.

[0077] Furthermore, it is also possible to manufacture the contact lens 10 not only by single-sided molding as described above, but also by using double-sided molding. In such a case, a molding surface 60 is provided which is formed to have substantially the same shape as the entire front surface of the lens including the front optical section 14 of the contact lens 10 of various lens power constituting the series contact lens. A lower mold 56 is prepared, and a mold 52 is prepared which has a mold cavity having a shape substantially identical to the entire target contact lens 10 including the front optical part 14. Then, as in the single-sided molding described above, the desired contact lens can be obtained by filling the molding cavities of the lower and upper molding molds 56, 54 with monomer material and promoting polymerization. In this way, the desired contact lens can be obtained directly by molding, and the cutting process can be omitted.

[0078] In addition, a large number of contact lenses manufactured with various edge radii, rate of change in lens size, or edge lift size were tested by over 50 people who have no eye disease and have experience wearing contact lenses. More than 100 eyes were evaluated using a lens with the appropriate power for the target eye for the monitor. In the following evaluation, the evaluation items were comfort, amount of lens movement, and visual stability. In addition, the wearer's comfort was evaluated by interviewing patients regarding foreign body sensation, irritation, etc. on a four-point scale of ``good,'' ``almost good,'' ``slightly poor,'' and ``poor.'' In addition, the amount of lens movement was measured when the lens was worn, and a movement of 0.2 to 0.6 mm was considered ``good.'' In addition, regarding visual stability, we asked questions about the stability of visual appearance when wearing the item.

Evaluation was made in four stages: "good", "almost good", "slightly poor", and "poor". Since the amount of evaluation carried out is enormous, we will omit the formation of each individual evaluation data here, and the tables below show the statistical processing of the large number of evaluation data obtained.

[0079] [Table 1] r(mm) 0.02 0.03 0.04 0.05 0.06 0.07 Comfort II A 〇〇〇 Δ X

〇: 80% or more targets are good

△: Less than 80%, 50% or more targets are good

: Less than 50% targets are good

[0080] Table 1 shows the results of an experiment to confirm the influence of edge curvature radius r on wearing comfort. Table 1 As is clear from the force, it was confirmed that a good wearing feeling could be obtained within the range of 0.03 mm ≤ r ≤ 0.05 mm, which is the structure according to the present invention. This result is because the size of the radius of curvature of the edge is related to the thickness of the lens, so if r < 0.03 mm, it will become sharp and irritating, while if r < 0.05 mm, it will feel thick. It is presumed that this is due to.

[0081] [Table 2]

〇: 80% or more targets are good

△: Less than 80%, 50% or more targets are good

X : Less than 50% targets are good

[0082] Table 2 shows the influence of the angle (a) formed by the tangent to the rear surface of the lens and the tangent to the peripheral end surface of the lens at the corner on wearing comfort, amount of lens movement, visual stability, bulbar conjunctival epithelial disorder, and sense of dryness. The results of the experiment are shown. Note that a lens with an edge radius: r= 0.04 mm was used as a lens in this experiment. As is clear from Table 2, within the range of 120° ≤ a ≤150° with the structure according to the present invention, it is possible to obtain good wearing comfort, the amount of lens movement, and visual stability, and the bulbar conjunctiva It was confirmed that there were no problems with epithelial damage or dryness. As a result, if α is less than 120°, the corners will become a bit sharp and cause irritation, while if α is less than 150°, the corners will essentially not be formed, and the conventional structure This is presumed to be due to the fact that there is no large difference between the two.

[0083] [Table 3] Lens position stability Visibility stability Comfort Bulb ϋ Upper insect damage ¾ Sensation Invention edge o O 0 〇 Ο Sharp edge o 〇 Δ XX Round edge XXX 〇 0

0: 80% or more targets are good

△: 8 (less than W, 50% or more targets are good)

X : Good for targets less than 50¾

[0084] Table 3 also lists three types of contact lenses (120 degrees, 135 degrees, 150 degrees) as examples having structures according to the present invention, based on the experimental results shown in Table 2. One typical example of a sharp edge structure (with δ 1 = 90 degrees in Fig. 10 (a = 90 degrees in Table 2)) as a comparative example, and one type of round edge structure (with a spherical cross section) as a comparative example. The results are shown in comparison with the general comments on the convex curved outer peripheral end surface connected to the inner and outer surfaces of the lens by a common tangent line (oc = 180 degrees in Table 2). The overall review of Table 3 also shows that the edge structure according to the present invention can exhibit a novel structure that is different from both sharp edge structures and round edge structures, and new functions and effects based thereon. This is what is understood.

[0085] [Table 4]

〇: 80% or more targets are good

△: Less than 80%, 50% or more targets are good

X : Less than 50% targets are good

[0086] Table 4 shows the results of an experiment to confirm the effect of the rate of change in lens size: A D on the wearing comfort, amount of lens movement, and visual stability. The lens used in this experiment had an edge radius: r = 0.04 mm, and an angle between the tangent to the rear surface of the lens and the tangent to the outer peripheral end surface of the lens at the corner: a = 135°. As is clear from Table 4, it was confirmed that within the range of 1% ≤ A D < 5%, which is the structure according to the present invention, good wearing comfort, lens movement amount, and visual stability can be obtained. It is presumed that this result is due to the fact that if the rate of change is too large, the lens shape will not fit sufficiently into the cornea.

[0087] [Table 5] h(mm) 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 Wearing comfort X 厶 OOO 〇〇 Δ X

〇: 80% or more targets are good

△: 80% reached, 50% or more targets are good

X : Less than 50% targets are good

[0088] Table 5 shows the results of an experiment to confirm the effect of edge lift: h on wearing comfort, amount of lens movement, and visual stability. The lens used in this experiment had an edge radius of r = 0.04 mm and an angle between the tangent to the rear surface of the lens and the tangent to the outer peripheral edge of the lens at the corner: α = 135°. As is clear from Table 5, it was confirmed that good wearing comfort, amount of lens movement, and visual stability could be obtained within the range of 0.04 mm ≤ h ≤ 0.12 mm with the structure according to the present invention. Ta. These results show that when h < 0.04 mm, a corner is formed, which causes irritation, while when h is 0.12 mm and h is too far away from the cornea, the positioning effect cannot be effectively achieved. It is presumed that this is due to this.

[0089] The above description of an embodiment of the present invention is merely an example, and the present invention is to be construed in a limited manner by the specific description of the embodiment. The present invention may be implemented in various modifications, modifications, improvements, etc. based on the knowledge of those skilled in the art, and as long as such embodiments do not depart from the spirit of the present invention. Needless to say, it is included within the scope of.

[0090] 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 as each embodiment of the present invention described below are both soft type lenses made of a highly water-containing soft material, similar to the contact lens 10 of the first embodiment. Since this is a contact lens, members and parts having the same structure as those in the first embodiment are designated with the same reference numerals as in the first embodiment in the drawings, so that the details thereof will be explained. Further explanations will be omitted. Further, a contact lens 80 as a 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. Therefore, only an explanatory diagram of an enlarged longitudinal section corresponding to Fig. 3 is shown in Fig. 6.

[0091] That is, the vertical cross-sectional shape of the lens outer circumferential end surface 34 changes as it goes from the lens front surface 24 to the lens rear surface 26, for example, as in the contact lens 80 as the second embodiment shown in FIG. It may also have a curved shape in which the curvature gradually changes. In this way, the longitudinal cross-sectional shape of the lens outer peripheral end surface 34 is not necessarily limited to a circular arc shape or a combination thereof, as in the first embodiment described above, but may be a shape expressed by a polynomial of quadratic or higher order. , a shape expressed by a conical curved surface, a shape expressed by trigonometric functions, and various other shapes can be adopted as appropriate.

[0092] Furthermore, in any of the embodiments described above, the lens rear surface 26 in the peripheral portion 20 is a concave curved line in the cross section in the lens radial direction, and is a curved surface that is slightly convex toward the front of the lens. At least a portion of the lens rear surface 26 may be formed into a straight line in cross section in the lens radial direction. As such an aspect, for example, FIG. 7 shows a contact lens 90 as a third embodiment. An annular connecting portion 92 is formed around the entire circumference of the contact lens 90 at a peripheral portion of the contact lens 90 and a radially intermediate portion of the inner surface of the contact lens 90 . Then, on the inner side of the lens in the radial direction across the annular connecting portion 92, a curved surface 94 whose cross section in the lens radial direction is a concave curved line and slightly convex toward the front of the lens is formed around the entire circumference of the peripheral portion 20. It is expanding and forming. On the other hand, on the outside in the lens radial direction across the annular connection part 92, the lens radial cross section is linear, and a tapered surface 96 inclined with respect to the lens center axis 12 extends around the entire circumference of the peripheral part 20. It is formed by The curved surface 94 and the tapered surface 96 are connected by the annular connecting portion 92, thereby forming the lens rear surface 26 as the inner surface of the peripheral portion 20. As shown in Fig. 8, in the contact lens 90, which has an obtuse angle of the rear connecting part 38 as a corner part: α,, the straight line forming the tapered surface 96: 11, and the lens outer peripheral end face 34. Tangent line: Determined by the angle formed by 12.

[0093]Furthermore, the shape in which at least a portion of the lens rear surface 26 is straight in the radial cross section of the lens is not limited to the shape of the third embodiment. For example, straight lines and curved lines may be formed alternately in the lens radial direction in the lens radial cross section, and multiple tapered surfaces may be formed in the lens radial direction, or the entire rear surface 26 of the lens may be Various shapes can be adopted as appropriate, such as a tapered surface that is straight in the directional cross section, or a plurality of tapered surfaces that have different inclination angles at different positions in the radial direction of the lens.

[0094] In addition, although not listed one by one, the present invention can be modified based on the knowledge of those skilled in the art. The present invention may be implemented in a manner with additions, modifications, improvements, etc., and as long as such embodiments do not depart from the spirit of the present invention, they are all included within the scope of the present invention. It goes without saying that there is one thing.

Claims

The scope of the claims

[1] A soft contact lens formed from a water-containing material and having an optical section at the center of the lens and a peripheral section at the outer periphery of the optical section, including the inner surface of the optical section and the At least one of the inner surfaces of the peripheral portion has an aspherical shape, and an edge lift is set on the inner surface of the peripheral portion that gradually moves away from the inner surface of the optical portion as it goes outward in the radial direction of the lens. The outer circumferential end surface of the lens is convex toward the outer circumferential side and has a smoothly continuous curved cross-sectional shape with no corners, and the outer circumferential end surface of the lens and the inner surface of the peripheral portion are The connecting portion of the lens is a corner having a cross-sectional shape of an obtuse angle _α , which is located at a distance X inward in the radial direction of the lens, and the separation distance is X. A soft contact lens characterized in that the force Omm<x≤0.1mm and the obtuse angle α is 120 degrees ≤ α≤ 150 degrees.

[2] The inner surface of the peripheral portion is a concave curved line in the radial cross section of the lens, and the obtuse angle: The soft contact lens according to claim 1, wherein:

[3] While the inner surface of the optical portion is aspherical, at least a portion of the inner surface of the peripheral portion is a straight line in a lens radial cross section, and this straight line and the 2. The soft contact lens according to claim 1, wherein the obtuse angle: oc is determined by an angle formed by a tangent to the outer peripheral end surface of the lens.

[4] According to any one of claims 1 to 3, the outer circumferential end surface of the lens has a cross-sectional shape with a radius of curvature: r of 0.03mm≤r≤0.05mm throughout. Soft contact lenses as described.

[5] The soft contact lens according to claim 4, wherein the radius of curvature of the outer circumferential end surface of the lens is constant throughout, and the cross-sectional shape of the outer circumferential end surface of the lens is arcuate.

[6] The soft contact lens according to any one of claims 1 to 5, wherein the edge lift size: h is 0.04mm≤h≤0.12mm.

[7] Lens size in swollen state in 20°C saline: D to 35°C saline

20

Lens size in the swollen state: D Change rate to: AD, formula: Δϋ = (D -D )/Ό X100(%)

20 35 20

The soft contact lens according to any one of claims 1 to 6, wherein the rate of change expressed as 1%≦AD≦5%.

The inner surface of the optical part has an eccentricity within the range of 0.2 to 0.7 and a vertex radius of curvature of 5. OOmn! The soft contact lens according to any one of claims 1 to 7, wherein the soft contact lens has an aspherical shape formed of an ellipsoid with a diameter of 10.0 mm.