JPH01500466A - hydrogel contact lenses - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] hydrogel contact lenses Background of the invention The present invention relates to contact lenses, and more particularly to soft contact lenses. Regarding its design and structure.

The present invention further relates to hydrogel contact lenses with low negative power.

Currently, contact lenses for correcting ametropia can correct most types of ametropia. Lenses constructed in this manner are available in a variety of types, models, and materials. but , these lenses are placed in close contact with the sensitive tissue of the cornea of the eye, making them difficult to use. Several problems therefore arise. Therefore, the design, prescription, and fitting of vision correction lenses In this case, it is necessary to fully consider the special characteristics of the corneal tissue.

The cornea is a non-vascular tissue. This is due to the presence of blood vessels in the cornea. This is because the transparency necessary to obtain this is impaired. Still a living organization Therefore, a supply of oxygen and nitrogen is necessary, and waste products from metabolism must be excreted. do not have. For this purpose, the cornea is moistened by successive new streams of lachrymal fluid, This tear fluid provides nutrients and removes metabolic wastes. Oxygen is absorbed around the exposed area of the eye. It dissolves directly into the tear fluid from the atmosphere and then diffuses from the tear fluid into the corneal tissue. sleeping When you close your eyes for a long time, the amount of oxygen reaching your cornea decreases. Even in such cases, the amount of oxygen necessary for metabolism is usually delivered to the cornea via the tear fluid. has reached.

When a contact lens is attached to the cornea for vision correction, tears form between the lens and the cornea. A thin film of liquid remains. However, this thin tear film is no longer exposed to the atmosphere and directly absorbs oxygen. There is no absorption. Therefore, the tear film between the lens and the cornea is kept well-oxygenated. Take some action, such as replacing it with a new solution or making the lens oxygen permeable. It is necessary to supply oxygen to the cornea under the contact lens.

It also helps eliminate waste by replacing the tear film between the lens and cornea with new tear fluid. is required. In fact, the cornea is unable to function properly even when there is a lack of oxygen supply or when it excretes waste products. Even if you don't, it's okay for a certain amount of time. Therefore, poly(methyl methacrylate) Even hard oxygen-impermeable contact lenses made of It is generally possible to use the device if it is worn for a period of time that is related to normal waking hours. Ru. Although the cornea can partially recover while the lens is not worn, the short-term and long-term chronic changes have been reported. Also, your eyelids may erode while you blink. When you push the lens in and out, the lens moves almost randomly across the corneal surface. Therefore, even with such lenses, it is possible to replace lachrymal fluid to some extent. this tear The fluid replacement effect is achieved by attaching a relatively small diameter lens only to the central part of the cornea. This is particularly effective when

Oxygen-permeable hydrogel contact lenses to reduce patient rejection is being developed. This lens is made of water-swellable synthetic resin and is made of water-swellable synthetic resin. This also allows some oxygen to diffuse through the lens body, leaving acid in the underlying tear film. Oxygen, thereby supplying oxygen to the cornea where the lens is attached. but, For example, the water content is somewhat low at 25-59% of the total weight of the hydrated lens, and it may be With thicker hydrogel lenses, the entire corneal need is reduced, especially when the eyelids are closed. Oxygen stops passing through in proportion to the amount of oxygen. Accordingly, such lenses should also be removed when sleeping. There is a need. Similarly, in the case of soft lenses, the diffusion of metabolic wastes should be sufficiently ensured. Therefore, waste products are removed by replacing lachrymal fluid by moving the lens. It will depend on. Soft lenses are constructed to cover the entire cornea. Moreover, since it tends to fit loosely against the contour of the cornea, it is difficult to properly replace the lachrymal fluid. If you want the lens to move appropriately to cause this, consider the shape of the lens. is necessary.

Allows contact lenses to be worn essentially continuously or for extended periods of time so that it can be worn for long periods of time, not only during waking hours but also during sleep. , thin lenses with low water content and thick lenses with high water content (the water content ratio depends on the weight of the lens). A range of about 40-90% of the amount) was developed. Such lenses are used when the eyelids are closed. When the eyes are open, the amount of oxygen supplied is very small, but when the eyes are open, there is sufficient oxygen supply. A large amount of oxygen can be passed through the cornea by diffusion, and the necessary oxygen can be supplied to the cornea. death However, these lenses require lens movement to remove metabolic waste products from the cornea. Therefore, we have no choice but to rely on a method that replaces the lachrymal fluid. In addition, existing long-term wear Hydrogel lenses are highly flexible, so they adhere tightly to the cornea, and the eyelids Movement becomes difficult. Therefore, the excretion of metabolic wastes is reduced by long-term wear lenses. This is an issue that remains for the current generation. In addition, long-term wear lenses are designed with lenses with low water content. Oxygen permeability varies depending on the type of lens, although it differs depending on the lens type. It doesn't change that much (±15%). In fact, the oxygen permeability of these lenses oxidation is insufficient, resulting in corneal hypoxia and accumulation of metabolic waste products.

Existing hydrogel contact lenses can only be used to treat very mild to mild myopia. This includes lenses with low negative power that are commonly prescribed to correct common conditions. In general, metabolic synthesis is slowed down due to insufficient oxygen permeation and small transfer rate. It was not possible to meet the requirement that the product can be worn for a long time without causing complications. fruit In the paper by Kenyon et al., ``Long-term continuous wear Effect of wearing time on complications” Ophthalmology (Ophthals+ol ogy) 1986. 93: As described in 231-6, epithelial Corneal changes such as microcysts, corneal thinning, and sometimes corneal ulcers can cause contact lenses. This occurs frequently in connection with long-term continuous wear of lenses, and these can be caused by hypoxia. This is thought to be due to the Lenses with low water content are currently the best for oxygen permeation. existing technology, and no further improvements can be made using existing technology. on the other hand , the thickness of the lens with high water content is thin enough to supply the oxygen required for corneal metabolism. However, other complications such as epithelial erosions occur. About this kind of action The article by Holden et al. 'Epithelial erosion caused by cancer', clinical and experimental optometroscopy Tory (C11nical and ExperimentaJ 0ptose try ) 6 9. 3: Reported in May 1986, pp. 103-107 Among these, this effect occurs only with very thin, high moisture content contact lenses. Insufficient lens mobility and a very thin tear film behind the lens can cause angular problems. It is stated that the cause may be that the membrane dries.

Although the development of soft contact lenses has been considered from an early stage, However, problems with regular and extended wear lenses have only recently been recognized. It was. Such problems include metabolic waste excretion, anatomical changes and physiology. Includes physical changes. The solution is to increase the water content of the lens and/or The idea is to design lenses with high oxygen permeability by reducing the thickness of the lenses. method has been adopted, the existing low negative power (-2,00 diopter) ) All long-wear lenses have similar oxygen permeability. For example: Low water content (35-45%) lenses typically have a center thickness of 0.03 mm; The center thickness of lenses with moderate water content (45-59%) is generally 0.05 mm. 1. The center thickness of lenses with high water content (60-90%) is generally 0.15+a+m. Ru. At any water content, if the lens is made thinner than the above, it may break easily as mentioned above. , lack of suitability for handling, insufficient discharge of metabolic residues and waste products, Satisfactory results have not been obtained due to corneal damage and other reasons.

Therefore, even today, it still maintains both sufficient oxygen permeability and good mobility on the cornea. can prevent corneal damage and eliminate metabolic residue and waste products. A hydrogel contact lens with high water content that is easy to handle and not easily broken. is needed.

Purpose of invention SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide an improved low-negative soft contact lens. The objective is to provide the configuration of the lenses.

Another object of the invention is to provide an improved hydrogel contact that is permeable to oxygen at high levels. Our goal is to provide trends.

Yet another object of the invention is to reduce damage to the corneal epithelium and possibly to Our goal is to provide improved hydrogel high water content contact lenses that eliminate problems such as There are many things.

Yet another object of the present invention is to provide improved corneal high water content that reduces the incidence of corneal damage. Our goal is to provide high-quality contact lenses.

Another object of the present invention is to properly move the lens relative to the cornea so that the back of the lens Novel contact lens composition configured to prevent waste buildup Our goal is to provide the following.

Yet another object of the present invention is to provide an improved hydrogel contact with superior handling properties. Our goal is to provide lenses.

Yet another object of the present invention is to provide a material that is strong yet flexible and that does not tear when stretched. improvements that allow it to recover its original shape without distortion or distortion in its optical quality. The purpose of the present invention is to provide high water content contact lenses.

Another object of the present invention is to provide an improved low-grade, high moisture content composition that is comfortable to wear. Our goal is to provide tact lenses.

Other objects and advantages of the invention will emerge from the following description with reference to the accompanying drawings. It will be clearer to those having ordinary knowledge in the relevant technical field.

Brief description of the drawing FIG. 1 shows a first embodiment (low power) of the hydrogel contact lens of the present invention. FIG.

FIG. 2 shows a second embodiment of the lens of the invention having a higher power than the lens of FIG. FIG. 1 is a cross-sectional view showing a gel contact lens.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, a soft contact lens embodying the present invention can be seen in its cross section. is designated as a whole by the reference numeral 10, and its axis of rotation is designated 11.

Lens 10 is a hydrogel material with a high water content of approximately 50% or 60% to 90%. It is made of aluminum and is permeable to high levels of oxygen. Also, lens 10 The negative power will be as low as -0,50 to -5,00 diopters (brightness). The power of the lens 10 in Fig. 1 is -0,50 to -3,50 diopter. The degree of 1/10 in Figure 2 is -3,00 to -7,00 diopters. - is.

The hydrogel material used in the contact lenses of the invention comprises at least 50% by weight or absorb enough water to form a hydrogel containing 60% water by weight. Any hydrophilic polymer can be used, whether synthetic or natural (collagen). Can be used. Such materials are well known to those skilled in the art and are described by Seldermann. No. 3,988,847 to U.S. Pat. Hydroxyethyl acrylate cross-linked with difunctional polymerizable monomers or Copolymer of hydroxyethyl methacrylate and N-vinylpyrrolidone, Karl ( No. 3,937,680 to Carle et al. Hydrocarbons cross-linked with difunctional polymerizable monomers such as glycol dimethacrylate Unsaturated organics such as xyethyl methacrylate, N-vinylpyrrolidone, and acrylic acid Copolymers with acids, Urbach U.S. Pat. No. 3.985.697 The combination of hydroxyethyl methacrylate and methacrylic acid as disclosed in Slightly cross-linked copolymers, a US patent from Tight et al. Acrylamide and N-vinyl as disclosed in U.S. Patent No. 4,430.458. Contains copolymers of pyrrolidone, methyl methacrylate, and methacrylic acid, etc.

The inner or back surface of the lens 10 is indicated generally by the reference numeral 12 and is (as shown). The back surface 12 of the lens is hyperbolic It can have any shape, such as a linear shape, a single-stroke linear shape, or an aspherical shape.

The opposite anterior surface 14 has a central curve 16 covering the optical zone 18 and the contact lens 10. Smoothly connect the peripheral curve 20 that engages with the peripheral curve 22, the center curve 16, and the peripheral curve 20. It is formed by a transition curve 24. The peripheral curve 20 gives the lens an annular convex rim or A bead portion 26 with increased thickness is formed, and this surface can be engaged with the eyelid. This allows the lens to move properly over the eye, while also keeping the eyelid in a circular shape. This allows it to slide smoothly over the lens. According to this degree of movement, metabolic aging Waste can be removed from the back of the lens. If mobility is insufficient, metabolic residual Debris builds up on the back of the lens and is harmful to the cornea.

In the case of a lens for high myopia, the bead 26 is located at a larger radius of the lens 10. It will extend across. Also, the total diameter of lens] and 0 are those that are normally used. smaller, from 12.5 to 14.5 mm, especially from 13.3 to 14.2 mm. , the preferred diameter is 14.0 m++. A large lens for such a small lens The resistance to movement is lower compared to the It will be done.

Preferably, the back surface 12 of the lens is formed by injection molding. From lathe processing This is because injection molding produces a smoother surface. This ultra-smooth finish on the back surface is the invention of this invention. This is the central feature of contact lenses, but it is an absolute measure of smoothness when it comes to contact lenses. Since there is no quantified scale for manufacturing by turning and polishing, "Injection molded surfaces that contain virtually no scratches that normally occur in molded surfaces" I decided to do so. When the surface of contact lenses is lathed and polished , it is thought that there will be more damage to the corneal epithelium because the surface will be rougher than the molded surface. Ru. As illustrated in U.S. Patent No. 4.121.898 or PCT/US 5 hepherd type as described in No. 84100742 A formula mold can be used. Similarly, U.S. Patent No. 3.691.263 and and rotary injection molding and base injection as disclosed in No. 4.155.962. It is also possible to use preformed front-turned lenses. Patents listed above , articles, and other materials are incorporated herein by reference. Enter.

A rear or back side quadratic curve 30 is formed at the outer edge of the back side 12. secondary music Line 30 improves alignment between the back surface 12 of the contact lens and the eye, thereby A side fitting curve is defined. The curve 30 joins both ends of the basic curve 32 of the optical range. The basic curve 32 is curved along the curved surface of the cornea. The electric film is more square Just as the radius is larger than the membrane, the quadratic curve 30 also has a larger radius than the basic curve 32. It has become. In a preferred embodiment, the peripheral curve 20 and the base curve 32 are short distances. The eyelids are parallel to each other, thereby making the edges thinner and making the eyelids look like contact lenses. 10 so that it can slide smoothly. Curve 30 is the distance of movement of lens 10 to determine the power and bead 26 thickness for lens control and comfort. It is important. The radius of curve 30 becomes 8.5 as the lens becomes larger. It is about 9.51. Also, regarding the length of curve 30, the larger the lens, the more It is shorter, approximately 1.10 mm. The radius of the basic curve 32 is 7.0 mm to 9.0 mm. It needs to be in the range of 0 mm, and the preferred range is 7, 5 mm to 8, 6mm or 7.7~8.3mm, special 1:8.0~8.3+*m or 7.8 ~8.1

As mentioned earlier, the water content of the lens 10 is approximately 50% or 60% to 90%. Yes, the central thickness will not exceed 0.08 μl. center like this By making the portion thinner, the oxygen permeability of the lens 10 can be made sufficiently high. , it becomes easier to wear the lens for a long time. When the moisture content is 60%, the center thickness is approximately 0. ．． 03m+*, and if the moisture content is 75%, it is approximately 0.08mm or less. do.

By making the peripheral thickness of the bead portion 26 sufficiently thick, the eyelid can easily hold the lens 10. Appropriate movement and handling suitability of pushing and moving the lens approximately 0.05mm on the cornea Make sure that the lens is properly aligned (centratron) and that the lens does not become distorted. It is possible to give the lens enough rigidity to do this. The thickness of the bead portion 26 is Usually 0.20 to 0.28+n, preferably 0.24m+s. Bead part 26 The width of the lens can be made less than 1.0 degrees, but in order to increase the movement of the lens, It is also within the scope of the present invention to make the width of the board part 1.0 to 1.5 fins. Also, before The diameter of the partial optical zone 18 can be made larger than 7.0 m, and the thickness can be made 0.24 m. The entire lens 10 can be used as an optical region up to m. However, in reality, the front light The diameter of area 18 should not exceed 10.5+u. rear optical area The diameter is a fitting curve that is independent of the diameter of the anterior optical zone and is essentially the average orthogonality of the cornea. determined by the diameter and the overall diameter of the lens.

Lens of the first embodiment according to the invention with a power of -2,50 diopters and a water content of 65% In the case of lens 10, the thickness at the center is 0.05 mm, the diameter of the optical zone is 8.5 mm, The thickness at that diameter is 0.105mm, and it covers an angle of 28.5 degrees. . The width of the transition angle is approximately 15 degrees and the radius is 9.6 mm. At the edge of the transition zone The peripheral thickness will reach 0.22 mm. Frequency - 0,50 diopter level In the case of lenses, the thickness is the same, but the thickness of the joint portion is approximately 0.06 On. the latter In the case of , the transition angle is almost the same as the former, but the radius is about 9.91 mm. Ma In addition, the peripheral thickness reaches approximately the same level.

A second embodiment of the lens according to the invention having a power of -2,50 diopters and a water content of 74%. In the case of lens 10, the thickness at the center is 0.08 mm, the diameter of the optical zone is 8.5 mm, and the thickness at the center is 0.08 mm. The thickness at the diameter is 0.14 mm. At this time, the radius of the transition angle is 8.2 mm, and the width becomes 17 degrees. The peripheral thickness at the edge of the transition zone reaches 0.24 m. frequency - In the case of a 0.50 diopter lens, the thickness will be the same, but the thickness of the junction will be approximately It becomes 0.09mm. In the latter case, the transition angle is almost the same but the radius is about 8.4 It becomes a crane, and the peripheral thickness reaches the same level.

The lens 10 of the third embodiment according to the present invention has a power of -0.50 to -5.00 Geo. The water content is between 70 and 85%, preferably 74%. The overall diameter is 14. 01m, the basic curve is 8.0mm or 8.3am, and the thickness at the center is approximately 0.01m. 0.07 mm or 0.08 mm, and the reverse side is obtained in connection with injection molding as mentioned above. It has an ultra-smooth surface finish. The thickness of the bead portion 26 of this lens is 0. , 20-0, 26 mm+, preferably about 0.24 m+*.

As is clear from the above detailed description, those skilled in the art will be familiar with the various aspects of the present invention. Any changes, modifications, or modifications may be made. Is such a change also within the spirit of the invention? The scope of the invention is limited only by the following claims. shall be included in the

FIG./.

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Claims (51)

[Claims] 1. Consisting of a hydrogel lens material having a water content of at least 50% of the total weight the main body has a cross-sectional shape with a low negative power; The main body has a front surface, a back surface, a front central optical zone, a peripheral portion, and generally the optical zone and the front surface. It has a peripheral area between the periphery and the peripheral area, The diameter of the main body is less than 14.5 mm, and the center thickness in the cross section of the main body is 0.08 mm or less, The thickness of the peripheral area in a cross section is greater than the thickness of the central part of the main body. Soft contact lenses. 2. Claim wherein the low negative power is -0.50 to -5.00 diopters. Lens as described in 1. 3. 2. The lens of claim 1, wherein the peripheral area of the back surface is concave. 4. The back surface is made ultra-smooth by molding, injection molding or rotary injection molding of the material. 2. The lens according to claim 1, wherein the lens is formed into a desired surface shape with a smooth surface finish. 5. The back surface is given the desired ultra-smooth surface finish by lathing and polishing the material. The lens according to claim 1, which is formed into a surface shape. 6. Said front surface is used for molding or injection molding or rotary injection molding or polishing of said material. The lens according to claim 4, wherein the lens is formed into a more desired surface shape. 7. The lens according to claim 1, wherein the diameter of the main body is 12.5 to 14.5 mm. 8. The lens according to claim 1, wherein the peripheral zone has a thickness of 0.25 mm or less. 9. The back surface of the main body has a basic curve of 7.0 to 9.0 mm in the rear optical region. The lens according to claim 1. 10. The lens of claim 1, wherein the back surface is hyperbolic. 11. The lens according to claim 1, wherein the back surface has a monocurvilinear shape. 12. The lens according to claim 1, wherein the back surface is aspherical. 13. the front surface includes a central optical curve in the optical zone and a peripheral edge adjacent to the peripheral edge; a smooth transition between and connecting the central optical curve and the peripheral optical curve; 2. The lens of claim 1, including a transition curve. 14. 2. The lens of claim 1, wherein the front optical zone has a diameter of less than 10.5 mm. . 15. The diameter of the front optical zone is between 7.0 mm and 8.5 mm, inclusive. The lens according to claim 14. 16. 2. The lens of claim 1, wherein the width of the peripheral zone is less than 1.0 mm. 17. The lens according to claim 1, wherein the width of the peripheral area is 1.0 to 1.5 mm. 18. the surface generally adjoins the base curve of the rear optical zone and the periphery; 2. The lens of claim 1, wherein the lens is formed by a posterior quadratic curve. 19. Claim 18: The basic curve is smoothly and directly continuous with the quadratic curve. Lenses listed in. 20. 19. The quadratic curve has a radius larger than the radius of the basic curve. Lenses listed. 21. The basic curve is formed to fit the cornea, and the quadratic curve is 19. The lens of claim 18, wherein the lens is shaped to fit a membrane. 22. The front surface includes a central optical curve, a peripheral curve parallel to the quadratic curve, and the central optical curve. The lens according to claim 18, comprising an optical curve and a transition curve connecting the peripheral curve. Z. 23. The transition curve depends on the power of the lens and the diameter of the front optical zone of the body. 19. The lens of claim 18, having a desired curvature. 24. the peripheral zone forming an annular lens rim extending from the anterior surface; The lens according to claim 1. 25. The thickness of the rim is such that the eyelid presses the body on the ocular surface. to the extent that the body has sufficient rigidity to not be distorted and to be properly aligned; 25. The lens according to claim 24, which has a size of . 26. The lens according to claim 1, wherein the water content is 71%. 27. The lens according to claim 1, wherein the water content is 74%. 28. A claim in which the moisture content is 50% and the center thickness is 0.03 mm. 1. The lens described in 1. 29. 2. The lens of claim 1, wherein the body has a diameter of less than 14.4 mm. 30. The lens according to claim 1, wherein the diameter of the main body is 13.3 to 14.2 mm. . 31. The lens of claim 1, wherein the diameter of the body is 14.0 mm. 32. A claim in which the moisture content is 60% and the thickness of the central portion is 0.04 mm. The lens according to item 1. 33. 2. A lens according to claim 1, wherein the water content is at least 60%. 34. the low negative power is -0.50 to -5.00 diopters, The diameter of the main body is about 14.0 mm, and the thickness of the center part in the cross section of the main body is It is about 0.07 to 0.08 mm, the peripheral zone forming an annular lens rim extending from the front surface; The thickness of the lens rim in cross section is 0.20 to 0.26 mm, and the thickness of the lens rim is 0.20 to 0.26 mm, and presses the main body on the surface of the eye, and the main body is not distorted and It is configured to have sufficient rigidity to perform proper alignment, and the back surface is The lens material has the desired back shape and ultra-smooth surface finish by injection molding. It is formed so that the back surface has a basic curve of approximately 8.0 to 8.3 mm in its optical region; a rear quadratic whose back surface is generally adjacent to the fundamental curve of the rear optical zone and the peripheral edge; The lens according to claim 1, wherein the lens is formed by a curved line. 35. 35. The lens of claim 34, wherein the peripheral area of the back surface is concave. 36. The back surface may have a hyperbolic shape, a monobola shape, or an aspherical shape. The lens according to claim 34. 37. The front surface includes a central optical curve of the optical zone and a peripheral curve adjacent to the peripheral edge. and a smooth transition curve connecting the central optical curve and the peripheral curve. 35. The lens of claim 34, wherein the lens is formed of a line. 38. 35. The lens of claim 34, wherein the front optical zone has a diameter of less than 10.5 mm. Z. 39. The diameter of the front optical zone is between and including 7.00 mm and 8.5 mm. 40. The lens of claim 39. 40. Claim 34: The basic curve is smoothly and directly continuous with the quadratic curve. Lenses listed in. 41. 35. The recorder according to claim 34, wherein the radius of the quadratic curve is longer than the radius of the basic curve. ns. 42. The basic curve is formed to fit over the cornea, and the quadratic curve 35. The lens of claim 34, wherein the lens is formed to fit over the membrane. 43. The front surface has a central optical curve, a peripheral curve parallel to the quadratic curve, and a front surface. 35. The method according to claim 34, further comprising a transition curve connecting the central optical curve and the peripheral curve. The lens included. 44. The transition curve depends on the power of the lens and the diameter of the front optical zone of the body. 44. The lens of claim 43, having a desired curvature. 45. 35. The lens of claim 34, wherein the rim has a thickness of 0.24 mm. 46. 35. The lens according to claim 34, wherein the water content is 70-85%. 47. The lens according to claim 1, wherein the water content is 74%. 48. 35. The lens of claim 34, wherein the base curve is 8.0 mm. 49. 35. The lens of claim 34, wherein the base curve is 8.3 mm. 50. The above-mentioned ultra-smooth surface finish is achieved by lathe processing and polishing to create soft contact lenses. Claim 34: The finish is substantially free from scratches that occur when a surface is formed. Lenses listed in. 51. The diameter of the main body is 14.0 mm, and the thickness of the center part of the main body is 0.0 mm. 35. The lens of claim 34, wherein the lens has a thickness of 0.24 mm and a thickness of the peripheral zone of 0.24 mm. Z.