Eyeball ciliary artery positioning device
The eyeball ciliary artery positioning device, which uses a ring-shaped positioning element and a threaded connection, solves the problem of determining the orientation of an excised eyeball, and achieves accurate positioning of the ciliary artery after fixation, thus ensuring the accuracy and stability of pathological sections.
Patent Information
- Application Number
- CN202422663884.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-01
- Publication Date
- 2025-10-31
- Estimated Expiration
- 2034-11-01
AI Technical Summary
In existing technologies, it is difficult to determine the location of the isolated eyeball, especially since the long posterior ciliary artery is not easy to observe after fixation, which makes it difficult to prepare tissue pathology slides and affects the diagnosis of drug ocular toxicity.
The upper and lower ring-shaped positioning components are respectively fitted onto the surface of the eyeball, and the spacing is adjusted by the connector to ensure that the positioning components are parallel to the ciliary artery. Combined with the extension and the screw-on knob, the eyeball is stably clamped and its orientation is determined.
Even after fixation, the position of the eyeball can still be accurately located, ensuring the accuracy of tissue sections, avoiding the instability of dye labeling due to the influence of fixative, and improving the reliability of pathological diagnosis.
Smart Images
Figure CN223500736U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of auxiliary instruments for the preparation of pathological specimens, and in particular to a ciliary artery positioning device for the eyeball. Background Technology
[0002] The eyeball is a specialized visual receptor, composed of the eyeball wall and its contents. The eyeball wall, from front to back, includes the cornea, iris, ciliary body, retina, choroid, sclera, and conjunctiva. The eyeball contents include aqueous humor, lens, and vitreous humor. The ophthalmic artery is the main blood vessel supplying blood to the structures within the orbit. It branches along the medial side of the orbit to form arteries including the ciliary arteries, central retinal artery, and supraorbital artery. The ciliary arteries mainly include the long posterior ciliary arteries, short posterior ciliary arteries, and anterior ciliary arteries. Two branches of the long posterior ciliary arteries pass through the sclera horizontally near the optic nerve and participate in forming the great arterial circle of the iris, providing blood supply to various orbital structures.
[0003] With the rise of novel ophthalmic drug delivery technologies and related new drug development, preclinical safety evaluation faces significant challenges. In evaluating drug toxicity, standardizing the location and size of organ and tissue samples is a prerequisite for accurate pathological diagnosis. In common histopathological slide preparation methods, transverse sections are taken from isolated eyeballs along the long axis of the optic nerve. However, in some cases, the macula is not sampled, making a sufficient diagnosis of drug ocular toxicity impossible. The macula is a unique physiological structure located in the central posterior pole of the retina in primates. Because it is the most concentrated area of retinal visual cells, this structure is highly sensitive to drug ocular toxicity. Furthermore, this area is closely related to the occurrence and development of various diseases. Monitoring pathological changes in the macula can help identify related lesions and indicate potential drug ocular toxicity. In animal experiments, histopathological examination is the gold standard for determining the target organ of drug toxicity. Fixing tissues and organs is a prerequisite for preserving the original structure of the organs and for further pathological diagnosis.
[0004] The ciliary arteries have specific locations within the ocular tissues. The long posterior ciliary artery (LCA) can be clearly observed during dissection, and its spatial position can be used to determine the orientation of the excised eye. For example, during pathological slide preparation, by confirming the location of the LCA, the specimen can be accurately sampled from all structures of the eyeball wall, including the macula, at a fixed angle. However, organs and tissues must be fixed before pathological slide preparation, i.e., the specimen is treated by soaking in a fixative. After a period of fixation, the LCA becomes difficult to detect with the naked eye, and the external shape of the eyeball is a regular, symmetrical structure, making it difficult to distinguish its specific orientation (e.g., dorsal, ventral, left, right) after excising the eye. This poses significant challenges to subsequent tissue preparation and sectioning.
[0005] In existing technologies, pens containing special dyes are often used to mark the eyeballs. However, experiments have shown that the dyes are not easy to stain the surface of the eyeballs and are prone to smudging, making the marked areas blurry. After tissues and organs are fixed with fixatives containing multiple components, the dyes are dissolved by the fixatives. The pigments in the dyes may also affect the colorophilicity of tissue cells, reducing the stability of tissue pathology slides and affecting the subsequent pathological diagnosis results. Utility Model Content
[0006] The technical problem to be solved by this utility model is to overcome the defect of the prior art in that it is difficult to determine the position of the isolated eyeball, and to provide an eyeball ciliary artery positioning device.
[0007] The present invention solves the above-mentioned technical problems through the following technical solution:
[0008] An ocular ciliary artery positioning device is used to fix the eyeball to confirm the position of the ciliary artery. The ocular ciliary artery positioning device includes an annular positioning element and a connecting element. The positioning element includes an upper positioning element and a lower positioning element, which are respectively fitted onto the surface of the eyeball. The upper positioning element and the lower positioning element are parallel to the ciliary artery and arranged at intervals. The connecting element includes a first connecting part and a second connecting part. The upper positioning element is connected to the first connecting part, and the lower positioning element is connected to the second connecting part. The first connecting part and the second connecting part are movably connected to adjust the distance between the upper positioning element and the lower positioning element.
[0009] In this design, the ciliary artery positioning device uses annular upper and lower positioning elements, each fitted onto the surface of the eyeball, to clamp the eyeball. By arranging the upper and lower positioning elements parallel to and spaced apart from the ciliary artery, their positions relative to the artery are fixed. This allows the positions of the upper and lower positioning elements to be adjusted based on the visible ciliary artery before fixing the eyeball specimen, thus securing the eyeball in a specific orientation. Because the eyeball is clamped and fixed, the positional relationship between the ciliary artery and the upper and lower positioning elements remains unchanged. Even after the eyeball has been treated with a fixative solution, making the ciliary artery invisible, the operator can still determine the eyeball's orientation based on the upper and lower positioning elements.
[0010] Preferably, the upper positioning member has a first extension extending to the first connecting portion, and the lower positioning member has a second extension at a position corresponding to the first extension, the second extension extending from the lower positioning member in a direction away from the eyeball to the second connecting portion.
[0011] In this design, two extensions extending to the connecting portion are provided on the upper and lower positioning components. This spacing between the connecting component and the eyeball surface prevents contact between the connecting component and the eyeball, thus avoiding damage. Positioning the extensions on the same side of the eyeball allows the operator to use the connecting component as a reference point to determine the left-right orientation of the eyeball. For example, during installation, the extension is placed on the right side of the eyeball. This ensures that when the eyeball is removed after treatment with the fixative, the relative position of the right side of the eyeball can still be identified by the position of the extension, preventing confusion due to the symmetry of the sphere. Simultaneously, the structure formed by the connecting component and the extensions also functions as a gripper, facilitating easy handling and avoiding direct contact with the eyeball surface.
[0012] Preferably, the first connecting part is a hollow outer sleeve, and the second connecting part is an inner sleeve disposed inside the outer sleeve; the outer sleeve and the inner sleeve are threadedly connected.
[0013] In this design, the first connecting part uses an outer sleeve, and the second connecting part uses an inner sleeve. The inner and outer sleeves are interlocked to achieve a movable connection between the two connecting parts. The distance between the two positioning parts is adjusted by threaded rotation. Compared with other movable connection methods, the threaded connection has better stability, allowing for more precise adjustment of the distance between the upper and lower positioning parts, thereby increasing the accuracy of positioning.
[0014] Preferably, the connector also includes a knob, the inner walls of the two ends of the knob along the axial direction are threaded to the outer wall of the outer sleeve and the outer wall of the inner sleeve, respectively, and the inner sleeve passes through the inner cavity of the knob.
[0015] In this solution, a knob is set and threadedly connected to the outer wall of the outer sleeve and the outer wall of the inner sleeve, so that the rotation of the knob can drive the inner sleeve to extend and retract within the inner cavity of the outer sleeve. This allows the operator to more easily adjust the distance between the upper and lower positioning parts by rotating the knob, making the operation more convenient.
[0016] Preferably, the outer sleeve and the inner sleeve are further provided with springs, and the two ends of the springs along the axial direction are fixedly connected to the inner cavity end faces of the outer sleeve and the inner sleeve, respectively.
[0017] In this design, springs are installed inside the outer and inner sleeves. When the initial length of the spring is less than the distance between the upper and lower positioning parts that are adapted to the eyeball size, the spring is stretched after adjusting the distance, thus applying a restoring force to the upper and lower positioning parts. This makes the upper and lower positioning parts more stable and secure, preventing the eyeball from slipping or rotating due to insecure fixing or accidents. When the initial length of the spring is set greater than the distance between the upper and lower positioning parts that are adapted to the eyeball size, the spring is compressed after adjusting the distance, thus applying a preload force to the upper and lower positioning parts. Furthermore, by installing springs inside the outer and inner sleeves, the connection structure between the outer and inner sleeves is made more stable.
[0018] Preferably, the inner diameters of the upper positioning member and the lower positioning member are equal.
[0019] In this design, the upper and lower positioning components are set with equal inner diameters, so that the upper and lower positioning components are symmetrically and coaxially fitted onto the spherical eyeball. This allows the upper and lower positioning components to apply a more uniform and symmetrical fixing pressure to the eyeball, preventing eyeball deformation caused by asymmetrical application of fixing force.
[0020] Preferably, the ends of the first connecting portion and / or the second connecting portion are provided with marking portions.
[0021] In this solution, by providing a marking part at the end of the first connecting part and / or the second connecting part, the operator can use the marking part as a reference to mark the vertical direction of the eyeball (for example, when installing the eyeball, the top of the eyeball is placed on the same side as the marking part). This allows the operator to still determine the top and bottom orientation of the eyeball by using the marking part determined during the previous installation after the fixation liquid has been soaked in it.
[0022] Preferably, the positioning element is made of metal, or the positioning element is made of any one of wood, rubber, or plastic.
[0023] In this scheme, by using metal as the material for the positioning element, the durability and stability of the positioning element can be increased. The material for the positioning element can be any one of wood, rubber or plastic. Using metal as the material for the positioning element can increase the durability and stability of the positioning element. Using elastic materials such as wood, rubber or plastic can make the positioning element less likely to damage the surface of the eyeball. The above materials do not react with the fixative and will not affect the preparation of the eyeball specimen.
[0024] Preferably, the ciliary artery positioning device further includes a buffer layer, which is attached to the annular inner wall of the upper and lower positioning members.
[0025] In this solution, by attaching a buffer layer to the annular inner wall of the upper and lower positioning components, the contact between the upper and lower positioning components and the eyeball is elastic, which reduces the impact on the eyeball, plays a buffering and shockproof role, and prevents damage to the eyeball during the fixing process of the positioning components.
[0026] Preferably, the material of the buffer layer is one or more of sponge, rubber, and silicone.
[0027] In this scheme, by using one or more of the following materials for the buffer layer—sponge, rubber, and silicone—the buffer layer becomes elastic, providing cushioning and shock absorption to prevent damage to the eyeball during the fixation process of the positioning component. The aforementioned materials do not react with the fixative and will not affect the preparation of the eyeball specimen.
[0028] The significant advantages of this invention are as follows: The ciliary artery positioning device employs annular upper and lower positioning elements, respectively fitted onto the surface of the eyeball, thereby clamping the eyeball and restricting its rotation relative to these elements. By arranging the upper and lower positioning elements parallel to and spaced apart from the ciliary artery, the orientation of the eyeball relative to the ciliary artery is determined. This allows the positions of the upper and lower positioning elements to be adjusted based on the visible ciliary artery before fixing the eyeball specimen, thus fixing the eyeball in a specific orientation and placing the ciliary artery between the upper and lower positioning elements. Because the eyeball is clamped and fixed, the positional relationship between the ciliary artery and the upper and lower positioning elements remains unchanged. Even after treatment with a fixative solution, the operator can still locate the ciliary artery along the gap between the upper and lower positioning elements. Attached Figure Description
[0029] Figure 1 This is a front structural diagram of the ciliary artery positioning device according to an embodiment of the present invention.
[0030] Figure 2 This is a side view of the ciliary artery positioning device according to an embodiment of the present invention.
[0031] Explanation of reference numerals in the attached figures:
[0032] Eyeball 1
[0033] Ciliary artery 2
[0034] Eyeball ciliary artery positioning device 3
[0035] Positioning component 4
[0036] Upper positioning component 100
[0037] Lower positioning component 200
[0038] Connector 150
[0039] First connecting part 10
[0040] First extension 11
[0041] Second connecting part 20
[0042] Second extension 21
[0043] Knob 160
[0044] Spring 170
[0045] Marking part 180 Detailed Implementation
[0046] The present invention will be described more clearly and completely below with reference to the accompanying drawings, but this does not limit the scope of the present invention to the present invention.
[0047] like Figure 1 and Figure 2 As shown, this embodiment provides an ocular ciliary artery positioning device 3 for fixing an eyeball 1 to confirm the position of the ciliary artery 2 of the eyeball 1. The ocular ciliary artery positioning device 3 includes an annular positioning member 4 and a connecting member 150. The positioning member 4 includes an upper positioning member 100 and a lower positioning member 200, which are respectively sleeved on the upper and lower surfaces of the eyeball 1. The upper positioning member 100 and the lower positioning member 200 are parallel to the ciliary artery 2 and arranged at intervals. The connecting member 150 includes a first connecting part 10 and a second connecting part 20. The upper positioning member 100 is connected to the first connecting part 10, and the lower positioning member 200 is connected to the second connecting part 20. The first connecting part 10 and the second connecting part 20 are movably connected to adjust the distance between the upper positioning member 100 and the lower positioning member 200.
[0048] Specifically, in this embodiment, the upper positioning member 100 and the lower positioning member 200 are two annular hoops, which are fitted onto the surface of the eyeball 1. The eyeball 1 is a sphere, and by setting the diameter of the annular hoops to be smaller than the diameter of the eyeball, the two annular hoops can clamp and fix the eyeball 1 from the top and bottom respectively.
[0049] In this embodiment, the ciliary artery positioning device 3 uses an annular upper positioning member 100 and a lower positioning member 200, which are respectively fitted onto the surface of the eyeball 1 to clamp the eyeball 1. Since the upper positioning member 100 and the lower positioning member 200 are parallel to the ciliary artery 2 and spaced apart, their positions relative to the ciliary artery 2 are fixed. Therefore, before fixing the eyeball 1 specimen, the positions of the upper positioning member 100 and the lower positioning member 200 can be adjusted based on the visible ciliary artery 2, fixing the eyeball 1 in a specific orientation. Because the eyeball 1 is clamped and fixed, the positional relationship between the ciliary artery 2 and the upper and lower positioning members 200 remains unchanged. Even after the eyeball 1 has been treated with a fixative (the fixative is the liquid used in the prior art for fixing and preserving eyeball specimens), making the ciliary artery 2 invisible, the operator can still determine the orientation of the eyeball based on the upper positioning member 100 and the lower positioning member 200.
[0050] like Figure 1 and Figure 2 As shown, the upper positioning member 100 is provided with a first extension 11 extending to the first connecting part 10, and the lower positioning member 200 is provided with a second extension 21 at a position corresponding to the first extension 11. The second extension 21 extends from the lower positioning member 200 in a direction away from the eyeball 1 to the second connecting part 20.
[0051] In this embodiment, by providing two extensions extending to the connecting portion on the two positioning members 4 respectively, the connecting member 150 is spaced from the surface of the eyeball 1, thus avoiding contact between the connecting member 150 and the eyeball 1 and preventing damage to the eyeball 1. Positioning the extensions on the same side of the eyeball 1 allows the operator to use the connecting member 150 as a reference to determine the left and right orientation of the eyeball 1 as needed. For example, during installation, the extension is placed on the right side of the eyeball 1, so that when the eyeball 1 is removed after treatment with the fixative, the relative position of the right side of the eyeball 1 can still be identified by the position of the extension, without confusion due to the symmetry of the sphere. Simultaneously, the structure formed by the connecting member 150 and the extensions also functions as a gripper, facilitating easy handling and avoiding direct contact with the surface of the eyeball 1.
[0052] In other embodiments, those skilled in the art may design the shape of the extension or not provide an extension as needed, so that the connector 150 is arranged directly along the surface of the eyeball 1.
[0053] like Figure 1 and Figure 2As shown, the first connecting part 10 is a hollow outer sleeve, and the second connecting part 20 is an inner sleeve located inside the outer sleeve; the outer sleeve and the inner sleeve are metal parts, nested together and connected by threads. By setting the first connecting part 10 as an outer sleeve and the second connecting part 20 as an inner sleeve, a movable connection between the two connecting parts is achieved; the distance between the two positioning parts 4 is adjusted by rotating the threads. Compared with other movable connection methods, the threaded connection has better stability, making the distance adjustment between the upper positioning part 100 and the lower positioning part 200 more precise, thereby increasing the positioning accuracy.
[0054] In other embodiments, those skilled in the art can select other movable connection methods according to actual needs, such as magnetic attraction or sliding connection through a slider structure, etc., to achieve an adjustable distance movable connection between the first connecting part 10 and the second connecting part 20, all of which can achieve the function of adapting to the specific size of the eyeball 1 and the clamping and fixing requirements of this solution.
[0055] like Figure 1 and Figure 2 As shown, the connector 150 also includes a knob 160. The inner walls of both ends of the knob 160 along the axial direction are threadedly connected to the outer wall of the outer sleeve and the outer wall of the inner sleeve, respectively. The inner sleeve passes through the inner cavity of the knob 160. In this embodiment, by setting the knob 160 and threading it to the outer wall of the outer sleeve and the outer wall of the inner sleeve, the rotation of the knob 160 can drive the inner sleeve to extend and retract within the inner cavity of the outer sleeve. This allows the operator to more easily adjust the distance between the upper positioning member 100 and the lower positioning member 200 by rotating the knob 160, making operation more convenient.
[0056] like Figure 1 and Figure 2 As shown, springs 170 are also provided inside the outer sleeve and the inner sleeve. The two ends of the springs 170 along the axial direction are fixedly connected to the inner cavity end faces of the outer sleeve and the inner sleeve, respectively. By installing springs 170 inside the outer sleeve and inner sleeve, when the initial length of spring 170 is less than the distance between the upper positioning member 100 and the lower positioning member 200 adapted to the size of the eyeball 1, after adjusting the distance, spring 170 is stretched and applies a restoring force to the upper positioning member 100 and the lower positioning member 200, making the fixation of the upper positioning member 100 and the lower positioning member 200 more stable and secure, preventing the eyeball 1 from slipping or rotating due to insecure fixation or accidents; when the initial length of spring 170 is set greater than the distance between the upper positioning member 100 and the lower positioning member 200 adapted to the size of the eyeball 1, after adjusting the distance, spring 170 is compressed and applies a preload force to the upper positioning member 100 and the lower positioning member 200; and by installing springs 170 inside the outer sleeve and inner sleeve, the connection structure of the outer sleeve and inner sleeve is made more stable, wherein the axial direction refers to the length direction along the connector 150.
[0057] The upper positioning member 100 and the lower positioning member 200 have the same inner diameter. The upper positioning member 100 and the lower positioning member 200 are symmetrically and coaxially fitted onto the spherical eyeball 1, so that the upper positioning member 100 and the lower positioning member 200 apply a more uniform and symmetrical fixing pressure to the eyeball 1, preventing deformation of the eyeball 1 due to asymmetrical application of fixing force.
[0058] like Figure 1 and Figure 2 As shown, a marking portion 180 is provided at the end of the first connecting portion 10. In this embodiment, the marking portion 180 is provided at one end of the first connecting portion 10 and is protruding. In other embodiments, the marking portion 180 may also be provided at the end of the first connecting portion 10 and / or the second connecting portion 20. The specific shape of the marking portion 180 can be designed according to actual needs, and the marking portion 180 may also be provided on the outer surface of the connector 150. By using the asymmetrically arranged marking portion 180 as a reference, the operator can use the marking portion 180 as a reference to mark the up and down direction of the eyeball 1 (for example, when installing the eyeball 1, the top direction of the eyeball 1 is placed on the same side as the marking portion 180). This allows the operator to still determine the top and bottom orientation of the eyeball 1 by using the marking portion 180 determined during the previous installation after soaking in the fixative solution.
[0059] The positioning element 4 is made of metal, or any one of wood, rubber, or plastic. Specifically, in this embodiment, the positioning element 4 is made of metal. Using metal as the material for the positioning element 4 increases its durability and stability. In other embodiments, the positioning element 4 can also be made of wood, rubber, or plastic; using an elastic material makes the positioning element 4 less likely to damage the surface of the eyeball. Those skilled in the art can also select other materials that do not react with the fixative and would affect the preparation of the eyeball specimen 1, as needed.
[0060] In this embodiment, the ciliary artery positioning device 3 further includes a buffer layer (not shown in the figure), which is affixed to the annular inner wall of the upper positioning member 100 and the lower positioning member 200. By affixing the buffer layer to the annular inner wall of the upper positioning member 100 and the lower positioning member 200, the contact between the upper positioning member 100 and the lower positioning member 200 and the eyeball 1 is elastic, reducing the impact on the eyeball 1 and playing a buffering and shockproof role, preventing damage to the eyeball 1 during the fixing process of the positioning member 4.
[0061] The buffer layer is made of one or more of sponge, rubber, and silicone. By using one or more of sponge, rubber, and silicone as the material, the buffer layer becomes elastic, providing cushioning and shock absorption to prevent damage to the eyeball 1 during the fixation process of the positioning element 4. In other embodiments, those skilled in the art can select other elastic materials for the buffer layer that do not react with the fixative and thus do not affect the preparation of the eyeball 1 specimen.
[0062] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship of the device or component during normal use. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation at any time, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model in this respect.
[0063] While specific embodiments of this utility model have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this utility model, but all such changes and modifications fall within the scope of protection of this utility model.
Claims
1. A ciliary artery positioning device for fixing the eyeball to confirm the position of the ciliary artery of the eyeball, characterized in that, The ciliary artery positioning device includes an annular positioning element and a connecting element. The positioning element includes an upper positioning element and a lower positioning element, which are respectively fitted onto the surface of the eyeball. The upper positioning element and the lower positioning element are parallel to the ciliary artery and arranged at intervals. The connector includes a first connecting part and a second connecting part. The upper positioning member is connected to the first connecting part, and the lower positioning member is connected to the second connecting part. The first connecting part and the second connecting part are movably connected to adjust the distance between the upper positioning member and the lower positioning member.
2. The ciliary artery localization device as described in claim 1, characterized in that, The upper positioning member has a first extension extending to the first connecting portion, and the lower positioning member has a second extension at a position corresponding to the first extension, the second extension extending from the lower positioning member in a direction away from the eyeball to the second connecting portion.
3. The ciliary artery localization device as described in claim 2, characterized in that, The first connecting part is a hollow outer sleeve, and the second connecting part is an inner sleeve disposed inside the outer sleeve; the outer sleeve and the inner sleeve are threadedly connected.
4. The ciliary artery positioning device as described in claim 3, characterized in that, The connector also includes a knob, the inner walls of the two ends of the knob along the axial direction are threadedly connected to the outer wall of the outer sleeve and the outer wall of the inner sleeve, respectively, and the inner sleeve passes through the inner cavity of the knob.
5. The ciliary artery positioning device as described in claim 3, characterized in that, The outer sleeve and the inner sleeve are also provided with springs, and the two ends of the springs along the axial direction are fixedly connected to the inner cavity end faces of the outer sleeve and the inner sleeve, respectively.
6. The ciliary artery positioning device as described in claim 1, characterized in that, The inner diameters of the upper positioning member and the lower positioning member are equal.
7. The ciliary artery positioning device as described in claim 2, characterized in that, The ends of the first connecting portion and / or the second connecting portion are provided with marking portions.
8. The ciliary artery positioning device as described in claim 1, characterized in that, The positioning element is made of metal, or it can be made of wood, rubber, or plastic.
9. The ciliary artery positioning device as described in claim 1, characterized in that, The ciliary artery positioning device further includes a buffer layer, which is attached to the annular inner wall of the upper positioning member and the lower positioning member.
10. The ciliary artery localization device as described in claim 9, characterized in that, The material of the buffer layer is one or more of sponge, rubber, and silicone.