JPS6138562Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a device for measuring chemical components of tears.

The medical significance of measuring the chemical components of tears has recently become clear (LG Carney et al.
Ophthalmo, 94B21 (1975)), and the clinical medical significance of its continuous measurement has also been elucidated (Kazuyuki Ikeda et al.
Proceedings of the 49th Society for Artificial Organs, page 456). However, the electrodes used by Ikeda et al. are glass electrodes, which have a large shape and lack flexibility, so they cannot be stably attached to the conjunctiva or cornea, and even once attached, the overall shape is large. It had the disadvantage of being easy to fall off. On the other hand, the inventors of the present invention attempted to solve the above-mentioned drawbacks by using an FET sensor using a field effect transistor (for FET sensors, see Japanese Patent Application Laid-Open No. 54-66194). FET sensor is approximately 0.5mm
Only the x5mm x 0.15mm sensor part is hard,
A feature of this device is that it is extremely light in weight, and one embodiment of a device using this device is shown in FIG. In the device shown in FIG. 1, the FET sensor is sealed in a silicon tube with an outer diameter of 1.0 mm and an inner diameter of 0.6 mm using a small amount of epoxy resin and silicone resin. Then, it is bent at a point Y that is a certain distance d from the tip X. In order to maintain this shape permanently, a resin such as epoxy resin may be filled up to the vicinity of the bending point Y and cured. Here, usually d=0.5~2.0cm, θ=
The angle is between 5° and 90°. It was confirmed that continuous monitoring could be performed by placing a device with this shape on the patient's lower eyelid and fixing the Z point with tape. However, although the method shown in Figure 1 has seen many improvements in size, weight, and ease of removal, it is still insufficient in terms of stably positioning the eye at a certain point and in consideration of the eyeball and conjunctiva. It was hot. After considering these points, the present inventors devised a device suitable for measuring the chemical components of tears.

That is, the present invention is a device for measuring the chemical components of tears, which comprises a sensor sensitive to the chemical components of tears and a support for fixing the sensor on the eyeball, and the support is configured to be attached to the surface of the eyeball. For measuring the chemical components of tears, the device has an inner surface shaped like a part of a spherical surface, and an opening into which a sensor is inserted so that the sensor is sensitive to tears on the surface of the eyeball. It is a device. By using the device of the present invention, the sensor can be stably fixed on the eyeball surface.

The present invention will be explained below with reference to the drawings.

Figure 2 a (cross-sectional view on the center line) and Figure 2
As shown in Figure b (plan view), the tip of the chemical-sensitive sensor is fixed to the inner surface of a support whose inner surface is part of a spherical surface, forming a device for measuring the chemical components of tears. . In this invention, the curvature of the inner surface is
It has been found that it is desirable to have a spherical surface with a distance A from the center of 7 mm or more and 15 mm or less in terms of the adhesion of the measuring device to the eyeball. On the other hand, the outer surface may be a flat surface as shown in FIG. 3, but it is desirable for wearability that it have a certain curvature like a contact lens. Further, it is desirable that the end portion has a peripheral curve (bevel) for the purpose of supplying nutrition to the eyeball and preventing damage. Here, it is necessary that the distance B between the ends of the inner surface be 30 mm or less in order to reduce the harm to the eyeballs. From the point of view of oxygen supply to the cornea, it is more preferable that B is 20 mm or less, but if it is too small, such as 3 mm, the holding stability of the sensor will deteriorate. Note that the thickness of the support is preferably about 0.1 to 1.0 mm. Furthermore, the distance C between the tip of the sensor inside the tube of the support and the inner surface of the support is preferably within 2 mm; if it is larger, the sensor will respond to changes in the chemical components on the eyeball. This is undesirable as it takes an unnecessary amount of time. C is 1.0 in terms of response time
It is particularly preferable that it is less than mm. However, if the tip of the sensor protrudes from the inner surface, it is dangerous as it may cause damage to the eyeballs. Next, regarding the piping to hold the sensor, the length D is 3 to 10
mm, and the inner diameter E of the pipe is preferably 0.3 to 5 mm. Furthermore, in the present invention, it is preferable that B is 5 to 15 mm, as this makes handling easier;
It is desirable that the diameter be 2.0 mm or less for better wearability.
Here, the material of the support must be lightweight and do not create pressure on the eyes, and is preferably an organic polymer material. Particularly desirable are polymer materials conventionally used in contact lenses, such as polymethyl methacrylate, silicone rubber, polycarbonate, and polyhydroxyethyl methacrylate resin.

As the sensor used in the present invention, any conventionally used sensor (glass electrode, Clark electrode, etc.) can be used as long as the shape allows, but from the viewpoint of small size and light weight, the
It is a FET sensor. FET sensors use IC processing technology, so it is extremely easy to make them compact and lightweight. For example, a size of 2 mm in length, 0.3 mm in width, and 0.15 mm in thickness can be easily achieved using conventional methods, and the weight is 1 mg.
It is equally easy to do the following. These are made by adding a small amount of water-resistant resin (e.g. epoxy, silicone resin) to the tip of the tube, which is then made of other water-resistant material.
After encapsulating it using a water-resistant resin, it may be fixed in the pipe on the support, or it may be fixed directly in the pipe on the support using a water-resistant resin. The types of sensors used in this invention are H ⁺ , Na ⁺ , C ^- , Ca ²⁺ ,
These include ion sensors such as HCO ³ _- , gas sensors such as O ₂ and CO ₂ , and sensors such as glucose, urea, and amino acids.

FIGS. 4a, b and c show what is shown in FIG. 2, with some parts missing. By doing so, oxygen transfer to the cornea can be facilitated. The shape of the cut may be linear as shown in FIG. 4a, or arcuate as shown in FIG. 4b. Of course, a structure having two (or more) missing portions on the top and bottom as shown in FIG. 4c may be used as well. In FIGS. 4a and 4b, F may be any value, and may be a corner value (if deeper than the center), but in that case, the piping for inserting the sensor only needs to be on the remaining spherical surface. FIG. 5 shows a case where the pipe of the support is not inserted perpendicularly to the spherical surface, but is inserted at a constant angle θ with respect to the tangent. Here, θ=5°~90
The angle is preferably 10° to 45°, and the other conditions are the same as those described above. A fitting such as that shown in FIG. 5 is particularly useful when the device is placed at the edge of the eye so that the sensor is held close to the lachrymal membrane.

Furthermore, in the present invention, the above-mentioned support whose inner surface is coated with a hydrogel-forming polymer is particularly excellent in terms of wearability.
As a polymer that forms a hydrogel, polyβ
Examples include hydroxyethyl methacrylate, polyvinylpyrrolidone, polyacrylamide, and polyvinyl alcohol. Copolymers thereof may also be used, particularly block or graft copolymers of β-hydroxymethyl methacrylate and methyl methacrylate, vinyl alcohol and ethylene,
Copolymers with vinyl chloride etc. are excellent. Of course, crosslinking after coating with these polymers is desirable from the viewpoint of strength, and for this purpose it is particularly preferable to copolymerize with a monomer such as glycidyl methacrylate.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a conventional tear chemical component measuring device, FIG. 2 a is a cross-sectional view of the central part of the tear chemical component measuring device of the present invention, and FIG. FIG. FIG. 3 is a cross-sectional view showing another embodiment of the device of the present invention, and FIGS. 4 a, b, and c are plane views showing other embodiments of the support of the present invention (a partially missing lens-shaped one). Figures 5a and 5b show cross-sectional views of another embodiment of the device of the present invention (an example in which the sensor is not inserted vertically into the support). In the figure, symbols 1 to 5 indicate the following.
1...Sensor, 2...Resin, 3...Connector, 4...Support, 5...Lead wire.

Claims (1)

[Claims for Utility Model Registration] 1. A device for measuring the chemical components of tears, which comprises a sensor sensitive to the chemical components of tears and a support for fixing the sensor on the eyeball, the support being attached to the surface of the eyeball. A lacrimal lens characterized by having an inner surface in the shape of a part of a spherical surface so that it can be worn, and an opening into which a sensor is inserted so that the sensor is sensitive to tears on the surface of the eyeball. Device for measuring chemical components. 2. The inner surface of the support is part of a spherical surface whose distance A from the center is 7 mm or more, and the support is a support whose distance B between the ends of the inner surface is 3 cm or less. The device according to scope 1. 3. The device according to claim 2, wherein the outer surface of the support is also spherical, and the support is shaped like a contact lens. 4 Utility model registration claim No. 3 in which the support device has a shape in which a part of a contact lens is missing
Apparatus described in section. 5. The device according to claim 1, wherein the sensor is fixed at a distance C within 2 mm from the inner surface of the support. 6. The device according to claim 1, wherein the sensor is a sensor sensitive to H ⁺ , Na ⁺ , K ⁺ , C ^- , O ₂ or CO ₂ . 7. The device according to claim 6, wherein the sensor is a FET sensor. 8. The device according to claim 1, wherein the material of the support is a polymer capable of forming a hydrogel.