JP7423342B2 - model eyes - Google Patents

Description

The present invention relates to an eye model used for measuring intraocular pressure using a tonometer.

Conventionally, in ophthalmology, the intraocular pressure of an eye to be examined has been measured using a contact tonometer such as a non-contact tonometer (gas injection tonometer) or a Goldmann tonometer. A non-contact tonometer and a contact tonometer measure the intraocular pressure of the eye to be examined using different measurement methods. In this case, for example, medical device certification bodies such as the Food and Drug Administration (FDA) in the United States require that when the same object is measured with a non-contact tonometer and a contact tonometer, the same intraocular pressure value can be measured. Standards for tonometers have been established to ensure that results are obtained. For this reason, model eyes are used to test whether non-contact tonometers and contact tonometers have measurement performance in accordance with the standards [including evaluation, inspection, adjustment, and calibration].

For example, Patent Document 1 discloses an eye model that can be used in both a non-contact tonometer and a contact tonometer to measure intraocular pressure. This model eye includes a main body having a storage chamber that contains liquid, and a lens that covers an opening formed in a wall of the storage chamber. The material used for this lens is silicone rubber or HEMA (Hydroxyethyl methacrylate), which has a flexibility similar to that of the cornea of the human eye.

Japanese Patent Application Publication No. 6-327632

By the way, when measuring the intraocular pressure of the subject's eye using a contact tonometer, if the amount of tear fluid covering the corneal surface of the subject's eye is too large or too small, an error will occur in the measurement result of the intraocular pressure value. The value cannot be measured accurately. For this reason, when testing a contact tonometer using a model eye, if the amount of liquid imitating tear fluid covering the surface of the model eye is not appropriate, the contact tonometer must be tested accurately. I can't.

When hydrophobic silicone rubber is used as the material for the lens of the model eye as described in Patent Document 1, the liquid in the storage chamber cannot penetrate the lens, which dries the lens and makes it difficult to measure intraocular pressure accurately. may become difficult. Furthermore, if HEMA is used as the material for the lens of the model eye, the liquid in the storage chamber will evaporate before it permeates from the back surface of the lens toward the front surface. Therefore, the amount of liquid covering the surface of the model eye may become too small or the lens may dry and harden, making it difficult to accurately measure intraocular pressure. As a result, it is difficult to accurately measure the intraocular pressure of the model eye of Patent Document 1 using a contact tonometer.

On the other hand, a non-contact tonometer is not affected by the amount of tear fluid covering the corneal surface of the eye to be examined, so it is difficult to accurately measure the intraocular pressure even when using the model eye described in Patent Document 1. Can be done. However, as mentioned above, it is difficult to accurately measure the intraocular pressure of the model eye of Patent Document 1 with a contact tonometer, so when a non-contact tonometer and a contact tonometer measure the same model eye, the same There is a possibility that the measurement result of the intraocular pressure value cannot be obtained.

The present invention has been made in view of these circumstances, and an object of the present invention is to provide a model eye that can prevent dryness.

A model eye for achieving the object of the present invention is a model eye used for intraocular pressure measurement, and includes a storage chamber for containing liquid, a casing having an opening in the wall of the storage chamber, and a lens covering the opening. and a lens having a back surface in contact with the liquid in the storage chamber and a front surface of the lens opposite to the back surface of the lens, wherein the lens transfers the liquid in the storage chamber from the back surface of the lens to the front surface of the lens. and soak it into the surface.

According to this model eye, the liquid in the storage chamber can always cover the front surface of the lens.

In the model eye according to another aspect of the present invention, the lens is formed of a material in which the amount of liquid that permeates into the front surface of the lens is equal to the amount of liquid that evaporates from the front surface of the lens. There is. This allows the lens front surface of the lens to be constantly covered with liquid, and also prevents the amount of liquid covering the lens front surface from becoming excessive.

In a model eye according to another aspect of the invention, the lens forms a layer of liquid on the front surface of the lens. This prevents the lens from drying out.

In the model eye according to another aspect of the present invention, the lens is formed of a hydrous material. This allows the liquid in the storage chamber to permeate from the back surface of the lens to the front surface of the lens.

In a model eye according to another aspect of the present invention, a lens is replaceably provided in the opening. Thereby, lenses can be easily replaced.

In the model eye according to another aspect of the present invention, the lens has an annular lens edge that contacts the peripheral edge of the opening in the casing, and a lens center that covers the opening, and is detachably attached to the casing. The present invention includes a lid that is attached to the casing, and includes an exposure window that exposes the center of the lens when the lid is attached to the casing, and a presser that holds the edge of the lens between the peripheral edge of the opening. This allows lenses to be easily replaced by simply removing the lid from the casing.

The present invention can prevent the model eye from drying out.

FIG. 1 is a schematic diagram of a model eye system in which intraocular pressure is measured using a tonometer. It is a sectional view of a model eye. It is an exploded sectional view of a model eye. FIG. 3 is an exploded cross-sectional view of the model eye with the lid removed. 3 is an enlarged view of the corneal model lens in FIG. 2. FIG. 6 is an enlarged view of the lens front surface of the corneal model lens shown within the dotted circle Q in FIG. 5. FIG.

FIG. 1 is a schematic diagram of a model eye system 9 in which intraocular pressure is measured by a tonometer 2. As shown in FIG. As shown in FIG. 1, the model eye system 9 includes a model eye 10 and an intraocular pressure adjustment device 20. The model eye 10 is set in an intraocular pressure adjustment device 20, and the intraocular pressure (the pressure of the liquid 50 within the model eye 10) is adjusted by the intraocular pressure adjustment device 20. This model eye 10 is subjected to intraocular pressure measurement using the tonometer 2 when the tonometer 2 is tested.

The tonometer 2 is not limited to the contact type tonometer illustrated in the figure, but also includes a non-contact type tonometer. Therefore, the model eye 10 is compatible with intraocular pressure measurement using both a non-contact tonometer and a contact tonometer, which have different measurement methods. Note that the tonometer 2 may be a multifunction device capable of performing various known measurements (for example, reflex measurement, keratometry, corneal pressure measurement, etc.) in addition to measuring the intraocular pressure of the eye to be examined.

[Intraocular pressure adjustment device]
The intraocular pressure adjustment device 20 includes a model eye support section 22, a main conduit 24, a manometer 26, a first branch conduit 28, a first connection conduit 30, a pressure gauge 32, and a second branch conduit 34. , a second connection pipe 36 , a third branch pipe 38 , a maintenance port 40 , a water level adjustment section 42 , a water level controller 44 , and a drainage pipe 46 .

The model eye support section 22 supports the model eye 10. The model eye support section 22 supports the model eye 10 so that the height position of the model eye 10 matches (including substantially matches) the baseline L0.

The main channel 24 has a shape extending in the horizontal direction, and one end thereof is connected to the storage chamber 18 (see FIG. 2) for the model eye 10, and the other end is connected to the manometer 26.

The manometer 26 (also referred to as a water column manometer) has a shape extending in the vertical direction, and has an upper end open to the atmosphere and a lower end connected to the main pipe 24. Therefore, the manometer 26 is connected to the accommodation chamber 18 (see FIG. 2) of the model eye 10 via the main conduit 24. The manometer 26 supplies the liquid 50 into the storage chamber 18 and applies pressure to the liquid 50 in the storage chamber 18 according to the water level (liquid level height) of the liquid 50 inside the manometer 26 . Thereby, by adjusting the height of the liquid 50 in the manometer 26, the intraocular pressure of the model eye 10 can be adjusted. Note that it is assumed that the specific gravity of the liquid 50 and the gravitational acceleration within the manometer 26 are constant.

As the liquid 50, for example, water, physiological saline, artificial lachrymal fluid (liquid imitating the tear fluid of the human eye), mercury (liquid metal), etc. are used. Note that the type of liquid 50 to be accommodated (filled) in the model eye 10 for measuring intraocular pressure is not particularly limited. Further, air may be included in the liquid 50.

The first branch pipe 28 is a T-shaped pipe provided in the middle of the main pipe 24 and branches the first connecting pipe 30 from the main pipe 24 . The first connecting pipe 30 has one end connected to the first connecting pipe 30 and the other end connected to the pressure gauge 32 .

The pressure gauge 32 (water pressure gauge) detects the water level of the liquid 50 in the manometer 26 as pressure (pressure display). This pressure gauge 32 is measured by the manometer 26 with the pressure set to "0 (mmHg)" when the level of the liquid 50 in the manometer 26 matches the baseline L0 (that is, the atmospheric pressure is set to 0 (mmHg)). The pressure of the liquid 50 being pressurized is detected. Thereby, the water level of the liquid 50 on the manometer 26 can be detected as pressure (gauge pressure). As a result, the pressure of the liquid 50 in the storage chamber 18 pressurized by the manometer 26 (model eye 10 intraocular pressure) can be quantified. Therefore, traceability of the calibration of the tonometer is ensured, so it is possible to comply with international standards set by certification bodies such as the FDA.

The second branch pipe 34 is a T-shaped pipe provided in the middle of the main pipe 24 and between the first branch pipe 28 and the manometer 26. is branching out. The second connecting pipe 36 has one end connected to the second branch pipe 34 and the other end connected to the water level adjustment section 42 . Note that a maintenance port 40 is connected to the middle of the second connection pipe 36 via a T-shaped third branch pipe 38 .

The water level adjustment section 42 includes a syringe 42a (cylinder) and an actuator 42b. The syringe 42a adjusts the level of the liquid 50 in the manometer 26 by injecting the liquid 50 into the main conduit 24 or suctioning the liquid 50 from the main conduit 24 through the second connection conduit 36. . Therefore, the intraocular pressure of the model eye 10 can be adjusted by driving the syringe 42a.

Here, the water level of the liquid 50 in the manometer 26 may be increased by the liquid 50 evaporating from the upper end side of the manometer 26 that is open to the atmosphere, or by the liquid 50 being evaporated from the upper end side of the manometer 26 which is open to the atmosphere, or by the liquid 50 being evaporated from the corneal model lens 14 (see FIG. 2) of the model eye 10 (described later). It decreases by seeping out. Therefore, even if the level of the liquid 50 in the manometer 26 decreases, the level of the liquid 50 in the manometer 26 can be kept constant by injecting the liquid 50 from the syringe 42a into the main conduit 24, that is, the eye of the model eye 10. The pressure can be adjusted to a constant level.

As the actuator 42b, various drive mechanisms capable of driving the syringe 42a, such as a motor drive mechanism or a linear motor, are used. This actuator 42b adjusts the height of the water level of the liquid 50 in the manometer 26 by driving the syringe 42a according to the input operation (water level adjustment operation) to the water level controller 44 by the operator, that is, the intraocular pressure of the model eye 10. Adjust.

Note that the water level adjustment unit 42 is not limited to having a syringe 42a, as long as it is possible to inject and drain the liquid 50 into the main pipe 24 (pressure adjustment), and may employ various known injection and draining mechanisms. good. Moreover, instead of adjusting the height of the water level of the liquid 50 in the manometer 26 by the water level adjustment part 42, a position adjustment part for adjusting the vertical position of the manometer 26 is provided as the water level adjustment part 42, so that the liquid level of the manometer 26 can be adjusted. The height of the water level of 50 may be adjusted.

The drain pipe 46 is connected to the storage chamber 18 (see FIG. 2) of the model eye 10, and is used to drain the liquid 50 from the storage chamber 18.

Note that there are pipes in the middle of the main pipe 24, between the first branch pipe 28 and the second branch pipe 34, in the middle of the second pipe, in the middle of the maintenance port 40, and in the middle of the drainage pipe 46. A stopcock 52 is provided to switch between opening and closing.

[Model eyes]
FIG. 2 is a cross-sectional view of the model eye 10. FIG. 3 is an exploded cross-sectional view of the model eye 10. FIG. 4 is an exploded sectional view of the model eye 10 with the outer lid 16 removed. As shown in FIGS. 2 to 4, the model eye 10 includes a casing 12, a corneal model lens 14 (corresponding to the lens of the present invention), an inner lid 15, and an outer lid 16.

The casing 12 has a hollow structure and includes a base portion 12a and a lens mounting portion 12b. A storage chamber 18 that accommodates the liquid 50 is formed by the inner surfaces (inner wall surfaces) of the base portion 12a and the lens mounting portion 12b.

Ends of the main pipe 24 and the drain pipe 46 are connected to the base portion 12a, and each end is opened within the storage chamber 18. Thereby, the liquid 50 can be accommodated (pressurized) in the accommodation chamber 18 or discharged (depressurized) from the accommodation chamber 18 by the intraocular pressure adjustment device 20 described above. Furthermore, a positioning pin 13 for positioning the inner lid 15 is provided protrudingly on the tip end surface of the base portion 12a on the lens mounting portion 12b side. Further, a threaded groove 19a for attaching the outer lid 16 is formed on the outer peripheral surface of the base portion 12a.

The lens mounting portion 12b is formed in a substantially cylindrical shape extending vertically from one surface of the base portion 12a. The tip of this lens mounting portion 12b is formed into a substantially hemispherical shape along a corneal model lens 14, which will be described later. An opening 12c is formed in the wall surface of the distal end of the lens mounting portion 12b (that is, the wall surface of the storage chamber 18).

The cornea model lens 14 is a soft, substantially cornea-shaped (so-called contact lens type) lens, and is placed (set) on the lens placement section 12b. Thereby, the corneal model lens 14 is placed on the lens placement part 12b so as to cover the opening 12c from the outside of the opening 12c (see FIG. 4). This corneal model lens 14 has an annular lens edge 14a that contacts the peripheral edge of the opening 12c in the casing 12, and a lens center portion 14b that covers the opening 12c. The cornea model lens 14 also has a lens back surface S1 that comes into contact with the liquid 50 in the storage chamber 18 through the opening 12c, and a lens front surface S2 that is the surface opposite to the lens back surface S1 and that faces the tonometer 2. and has. The material and function of the corneal model lens 14 will be described later.

The inner lid 15 constitutes the lid of the present invention together with the outer lid 16 described later, and is a presser lid that presses the cornea model lens 14 against the lens mounting portion 12b. The inner lid 15 is removably placed on the base portion 12a so as to cover the lens placement portion 12b and the corneal model lens 14. The inner lid 15 is formed in a substantially cylindrical shape, and one end thereof (on the base portion 12a side) is formed in a substantially flange shape. An insertion hole (not shown) into which the positioning pin 13 is inserted is formed at one end of the inner lid 15 . Thereby, the inner lid 15 is positioned with respect to the casing 12.

Further, a first exposure window 15a and a lens holding portion 15b are provided on the other end side of the inner lid 15 opposite to the one end side. The first exposure window 15a exposes the lens center portion 14b to the outside when the inner lid 15 is attached to the casing 12.

The lens holding portion 15b constitutes a peripheral portion of the first exposure window 15a within the inner lid 15. When the inner lid 15 is attached to the casing 12, the lens holding part 15b clamps and fixes the lens edge 14a between the lens holding part 15b and the peripheral edge of the opening 12c. Note that, when the inner lid 15 is removed from the casing 12, the lid holding portion 16b releases the clamping fixation of the lens edge 14a.

The outer lid 16 is detachably attached to the base portion 12a so as to cover the inner lid 15. This outer cover 16 is formed in a substantially cylindrical shape, and an engaging pawl 19b that threadably engages with a thread groove 19a is formed on the inner peripheral surface of one end side (base portion 12a side). By engaging the engaging claws 19b with the screw grooves 19a, the outer cover 16 is removably attached to the base portion 12a. At this time, since the outer lid 16 is not in contact with the corneal model lens 14, even if the outer lid 16 is attached to the casing 12 while being rotated, the corneal model lens 14 is prevented from being deformed or damaged.

Further, a second exposure window 16a and a lid holding part 16b are provided on the other end side of the outer lid 16 opposite to the one end side. The second exposure window 16a exposes the lens center portion 14b to the outside through the first exposure window 15a when the outer cover 16 is attached to the casing 12. This makes it possible to measure the intraocular pressure of the model eye 10 using the tonometer 2.

The lid holding part 16b constitutes the peripheral edge of the second exposure window 16a in the outer lid 16. When the outer lid 16 is attached to the casing 12, the lid holding portion 16b fixes the inner lid 15 to the casing 12 by pressing the lens holding portion 15b toward the lens mounting portion 12b. Thereby, the lens edge 14a is clamped and fixed between the lens presser 15b and the peripheral edge of the opening 12c.

Note that the lid holding portion 16b releases the fixation of the inner lid 15 to the casing 12 when the outer lid 16 is removed from the casing 12. Thereby, the inner lid 15 can be removed from the casing 12 and the clamping and fixing of the lens edge 14a can be released. As a result, the corneal model lens 14 can be removed from the casing 12. Therefore, when the corneal model lens 14 changes over time, the corneal model lens 14 can be easily replaced by simply removing the outer cover 16 and the inner cover 15 from the casing 12 in order.

[Cornea model lens]
FIG. 5 is an enlarged view of the corneal model lens 14 in FIG. 2. Moreover, FIG. 6 is an enlarged view of the lens front surface S2 of the corneal model lens 14 shown within the dotted circle Q in FIG. In addition, in FIGS. 5 and 6, illustration of the inner cover 15 and the outer cover 16 is omitted in order to prevent the drawings from becoming complicated.

As mentioned above, HEMA, which is the lens material described in Patent Document 1, is a low water content material with a water content (weight water content) of 40% or less. For this reason, if the corneal model lens 14 is formed using HEMA, the liquid 50 in the storage chamber 18 will evaporate before it permeates from the back surface S1 of the lens toward the front surface S2 of the lens. The lens 14 will dry and harden.

Therefore, as shown in FIG. 5, in this embodiment, the cornea model lens 14 is made of a highly water-containing material (equivalent to that of the human eye) that allows the liquid 50 in the storage chamber 18 to penetrate from the back surface S1 of the lens to the front surface S2 of the lens. It is made of hydrophilic material). This highly water-containing material is defined as follows: where P1 is the amount of liquid 50 that permeates from the back surface S1 of the lens to the front surface S2 of the lens, and P2 is the amount of evaporation of the liquid 50 that evaporates from the front surface S2 of the lens. In addition, the corneal model lens 14 is made of a material with a moisture content such that the permeation amount P1 and the evaporation amount P2 per unit area satisfy the relationship of permeation amount P1≈evaporation amount P2 under a predetermined temperature and humidity environment. Therefore, the water content of the highly water-containing material has a predetermined lower limit. This lower limit value is determined by experiments, simulations, etc. Note that the predetermined temperature and humidity environment is a general intraocular pressure measurement environment, for example, a temperature of 10 to 40° C. and a humidity of 10 to 95% (no condensation).

As shown in FIG. 6, a highly water-containing material in which the amount of penetration P1 is equal to (including being approximately equal to) the amount of evaporation of the liquid 50 from the lens front surface S2 side (the amount of penetration P1≈the amount of evaporation P2 is satisfied) By forming the cornea model lens 14 with a highly hydrous material), at least the lens front surface S2 of the lens central portion 14b can be covered by the liquid 50 that has permeated into the lens front surface S2 from inside the storage chamber 18. . As a result, a liquid layer 50a imitating a tear film can be formed on the lens front surface S2, thereby preventing the corneal model lens 14 from drying and hardening. As a result, measurement of intraocular pressure using the contact tonometer 2 is prevented when the corneal model lens 14 is dry and hardened.

In addition, when measuring the intraocular pressure of the model eye 10 using the contact-type tonometer 2, accurate intraocular pressure measurement is possible not only when the amount of liquid 50 covering the lens front surface S2 is too small but also when it is too large. It becomes difficult. For this reason, it is preferable that the thickness of the liquid layer 50a falls within a certain range suitable for measuring intraocular pressure with the contact-type tonometer 2 under the above-mentioned predetermined temperature and humidity environment. In other words, an upper limit is set for the moisture content of highly water-containing materials. This upper limit value is also determined through experiments, simulations, etc. For this reason, it is preferable to form the corneal model lens 14 with a material having a water content that satisfies the above-mentioned amount of penetration P1≈amount of evaporation P2.

Examples of the highly water-containing material of this embodiment include a copolymer mainly composed of MMA (Methyl Methacrylate Monomer) and N-VP (N-Vinylpyrrolidone). . More specifically, a copolymer of DMMA (N,N-dimethylacrylamide) and N-VP can be mentioned as an example. Note that the highly water-containing material of this embodiment is not limited to the above-mentioned copolymer, but is a material that satisfies the above-mentioned relationship between the amount of permeation P1 and the amount of evaporation P2, that is, the liquid 50 is used on the lens front surface S2. There are no particular limitations as long as the material penetrates into the area. Note that even if the above-mentioned copolymer is partially contained, the liquid 50 does not penetrate to the lens front surface S2 and evaporates, that is, the corneal model lens 14 dries and hardens. is excluded.

[Effects of this embodiment]
As described above, in this embodiment, the cornea model is made of a material (high water content material that satisfies penetration amount P1≒evaporation amount P2) that allows the liquid 50 in the storage chamber 18 to penetrate from the back surface S1 of the lens to the front surface S2 of the lens. Since the lens 14 is formed, the liquid layer 50a can be constantly formed on the lens front surface S2. This prevents the corneal model lens 14 from drying and hardening under a predetermined temperature and humidity environment (intraocular pressure measurement environment). As a result, the intraocular pressure of the model eye 10 can be accurately measured even with the contact-type tonometer 2, so that when the same model eye 10 is measured with the non-contact and contact-type tonometers 2, the same intraocular pressure can be measured. The measurement result of the value is obtained.

Furthermore, by forming the cornea model lens 14 with a material such that the thickness of the liquid layer 50a falls within a certain range suitable for intraocular pressure measurement under a predetermined temperature and humidity environment, the liquid 50 that covers the lens front surface S2 The amount can be adjusted appropriately. Thereby, the intraocular pressure of the model eye 10 can be measured more accurately using the contact-type tonometer 2. As a result, the effect that the same intraocular pressure value measurement results are obtained when the same model eye 10 is measured with the non-contact and contact tonometers 2 can be further enhanced.

Furthermore, in this embodiment, the corneal model lens 14 can be replaced simply by removing the outer lid 16 and the inner lid 15 from the casing 12, so if the corneal model lens 14 changes over time, the corneal model lens 14 can be easily replaced. can do.

[others]
In the above embodiment, the model eye 10 whose intraocular pressure is adjusted by the intraocular pressure adjustment device 20 having the manometer 26 has been described as an example, but the model eye 10 whose intraocular pressure is adjusted by various known intraocular pressure adjustment devices 20 The present invention is applicable to

In the above embodiment, the casing 12 and outer lid 16 of the model eye 10 are illustrated in FIG. It is not limited and can be changed as appropriate. Further, in the above embodiment, the cornea model lens 14 is detachably fixed to the casing 12 by the outer cover 16 via the inner cover 15, but the cornea model lens 14 may be fixed only by the outer cover 16. Alternatively, the corneal model lens 14 may be fixed using various fixing members or holding members other than the inner lid 15 and the outer lid 16.

In the embodiment described above, the corneal model lens 14 is detachably provided in the opening 12c of the casing 12, but for example, if the model eye 10 is a disposable type, the cornea model lens 14 is non-removably provided in the opening 12c. It may be. Further, in the above embodiment, the cornea model lens 14 covers the opening 12c from outside the opening 12c, but it may cover the opening 12c from the inside of the opening 12c (inner wall side of the storage chamber 18). .

In the above embodiment, the model eye 10 having the corneal model lens 14 in the shape of a cornea has been described as an example, but the present invention is applied to a model eye 10 for intraocular pressure measurement having lenses in various shapes such as a convex lens shape, for example. It is possible.

The cornea model lens 14 of the above embodiment has translucency, but the lens of the present invention is suitable for use with various cornea models (corneal surface models, It may have a light-shielding property as long as it is made of a highly water-containing material and can be used for intraocular pressure measurement with each tonometer, and is not necessarily limited to an optical element.

In the above embodiment, the model eye 10 that is commonly used for measuring intraocular pressure with a contact type and a non-contact tonometer 2 has been described as an example. The present invention is also applicable to the model eye 10 used only for intraocular pressure measurement (contact type).

2 Tonometer 9 Model eye system 10 Model eye 12 Casing 12a Base part 12b Lens mounting part 12c Opening part 14 Corneal model lens 14a Lens edge part 14b Lens central part 15 Inner lid 15a First exposure window 15b Lens holding part 16 Outer lid 16a Second exposure window 16b Lid holding part 18 Storage chamber 19a Thread groove 19b Engaging claw 20 Intraocular pressure adjustment device 22 Model eye support part 24 Main conduit 26 Manometer 28 First branch conduit 30 First connection conduit 32 Pressure gauge 34 Second branch line 36 Second connection line 38 Third branch line 40 Maintenance port 42 Water level adjustment part 42a Syringe 42b Actuator 44 Water level controller 46 Drain line 50 Liquid 50a Liquid layer 52 Stop cock L0 Baseline P1 Penetration amount P2 Evaporation amount S1 Lens back surface S2 Lens front surface

Claims (6)

In the model eye used for intraocular pressure measurement,
a casing having a storage chamber for containing a liquid and an opening in a wall of the storage chamber;
a lens that covers the opening and has a lens back surface that is in contact with the liquid in the storage chamber, and a lens front surface that is opposite to the lens back surface;
Equipped with
the lens allows the liquid in the storage chamber to penetrate from the back surface of the lens to the front surface of the lens ;
A model eye , wherein the lens is formed of a copolymer containing methyl methacrylate and N-vinylpyrrolidone . 2. The lens is formed of a material such that the amount of penetration of the liquid into the front surface of the lens is equal to the amount of evaporation of the liquid from the front surface of the lens. Model eyes. The model eye according to claim 1 or 2, wherein the lens forms a layer of the liquid on the front surface of the lens. The model eye according to any one of claims 1 to 3, wherein the lens is made of a hydrous material. The model eye according to any one of claims 1 to 4, wherein the lens is replaceably provided in the opening. The lens has an annular lens edge that abuts a peripheral edge of the opening in the casing, and a lens center that covers the opening,
comprising a lid that can be detachably attached to the casing,
5. When the lid is attached to the casing, the lid includes an exposure window that exposes the center portion of the lens, and a presser portion that holds the edge of the lens between the peripheral portion of the opening. Model eye described in.

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