JP4674893B2 - contact lens - Google Patents

Description

The present invention relates to an improvement of contact lenses, particularly hard contact lenses.

Conventionally, by providing an index on the lens surface of a toric contact lens, the offset between the cylinder axis and the ballast axis is identified, and whether rotation of the lens placed on the cornea is prevented as intended There is known a method of inspecting (see Patent Document 1).
Further, the provisional lens having an index on the lens surface is worn by the lens user to measure the optical characteristics of the eye, the optical information of the lens user's eye including aberration information is acquired, and the temporary lens is A method of manufacturing a contact lens to be processed is known (see Patent Document 2).

By the way, since the cornea is an avascular tissue, when the cornea is covered with a lens by wearing a hard contact lens, oxygen supply to the cornea becomes a problem, but this oxygen supply allows oxygen to pass through the lens material. When the contact lens moves on the cornea due to blinking, the tear fluid interposed between the lens and the cornea is exchanged in the bevel region on the rear surface of the lens.
In this case, the latter is important for oxygen supply to the cornea. This is because tear exchange not only supplies new oxygen but also excretes corneal metabolites to maintain the function of the cornea.

For this reason, the wearing state of the contact lens is inspected, and it is checked whether or not tear fluid is properly present in the bevel region of the lens. In this case, there are several methods for inspecting the wearing state of the contact lens, but usually the fluorescein dye is injected into the tear fluid after wearing the lens, and the state of the specific tear film formed between the lens and the cornea Therefore, a method for inspecting the wearing state has been implemented.

FIG. 5 is a diametrical sectional view of a conventional hard contact lens placed on the cornea, which is formed between the lens and the cornea, which is manifested by injecting fluorescein dye into tear fluid. An example of a unique tear film is shown. As shown in FIG. 5, in the lens central region 20 (defined by the base curve 22), there is a slight tear film 25 a below the lens, and the bevel region 21 (intermediate curve) outside the lens central region 20. A relatively thick tear film layer 25b is formed.

And according to this conventional lens wearing state inspection method, the lens moves smoothly with blinking by irradiating the measuring light with the lens user wearing the contact lens and observing with a slit lamp microscope, Whether or not tears are appropriately exchanged in the bevel region has been determined based on experience. Therefore, in order to realize an appropriate lens wearing state for the lens user, it is often necessary to wear a plurality of contact lenses.

In this case, it may be possible to check the degree of tears entering the bevel area by providing some index on the lens surface, but depending on the index provided in the conventional lens as described above, The condition of tears could not be checked.
JP-T-2001-507136 JP 2003-15093 A

Therefore, the problem of the present invention is that it is possible to easily check the degree of tears entering the bevel region of the contact lens placed on the cornea, and for the contact lens to be appropriately exchanged for tears and to obtain a good wearing state. It is to be able to quickly and accurately determine whether or not it is possible.

In order to solve the above problems, according to the present invention, in a contact lens having a lens rear surface comprising a circular lens central region and an annular bevel region provided outside the circular lens central region, the transition portion of the lens rear surface at the lens front surface the corresponding region, e Bei an index for checking the penetration of the tear with respect to the bevel region, the region corresponding to the transition of the lens rear surface in the front lens surface, when viewed diametrical cross section of the lens The line extending perpendicularly to the front curve of the front surface of the lens from the transition portion and the front curve intersect, and the indicator has a width of 0.01 to 0.1 mm and a depth of 0.1 mm. A contact lens having a groove of 001 to 0.1 mm is formed.

In order to solve the above-mentioned problems, and according to the present invention, in a contact lens having a lens rear surface comprising a circular lens central region and an annular bevel region provided outside the circular lens central region, The region corresponding to the transition portion is provided with an index for checking the degree of tears entering the bevel region, and the region corresponding to the transition portion of the rear surface of the lens on the front surface of the lens is a cross section in the diametrical direction of the lens. The line extending perpendicularly to the front curve of the lens front surface from the transition portion and the front curve intersect, and the indicator is a strip-shaped printed thin film having a width of 0.01 to 0.1 mm The contact lens characterized by comprising is comprised.

According to a preferred embodiment of the present invention, a plurality of the indicators are arranged at intervals from each other along a circumference centered on the center of the lens, or a circle centered on the center of the lens. Or it has the shape of a concentric circle, or is formed in dot shape.

According to the present invention, with the contact lens worn by the lens user, the observation dye is injected into the tear fluid, and then irradiated with the measurement light, and the index provided on the front surface of the lens is observed with a slit lamp microscope. By doing so, it is possible to easily check the degree of tears entering the bevel region, and whether or not appropriate tear fluid is exchanged in the bevel region and whether a good wearing state is obtained. It is possible to quickly and accurately determine whether or not.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a plan view of a contact lens (hard contact lens) according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view along the diameter direction of the lens of FIG. 1 placed on the cornea. Referring to FIGS. 1 and 2, the contact lens of the present invention comprises a circular lens central region 1 whose rear surface is defined by a base curve 4 and an annular bevel region 2 provided on the outside thereof. The lens front surface includes a substantially circular lens central region 5 defined by the front curve 6 and an annular peripheral region 7 provided outside the lens central region 5.

Further, when the cross section in the diametrical direction of the lens is viewed, a line extending perpendicularly to the front curve 6 on the front surface of the lens from a transition portion 8 from the lens central region 1 to the bevel region 2 on the rear surface of the lens. At the position where the front curve 6 and the front curve 6 intersect, the groove 3 is engraved so as to form a circle centered on the center of the lens. The groove 3 functions as an index for checking the degree of tears entering the bevel region 2.

  This index is not limited to that of this embodiment. For example, the index may be provided at the transition portion 8 from the lens central area 1 to the bevel area 2 on the rear surface of the lens, or the index may be You may provide in the area | region different from this Example corresponding to the transition part 8 of the lens rear surface in the lens front surface.

Further, as shown in FIG. 3A, a plurality of arc-shaped grooves 12 may be formed at intervals from each other along a circumference centered on the center of the lens. The index may be configured by imprinting a concentric groove on the lens surface with the center of the lens as the center. Alternatively, as shown in FIG. 3B, a dot-like recess 13 may be provided on the lens surface as an index.
When the indicator is composed of a groove, the groove preferably has a width of 0.01 to 0.1 mm and a depth of 0.001 to 0.1 mm. The diameter is preferably 0.002 to 0.1 mm and the depth is 0.001 to 0.05 mm.
Further, the index may be printed on the lens surface, and in this case, the index is preferably made of a strip-shaped printed thin film having a width of 0.01 to 0.1 mm.

  Thus, the contact lens according to the present invention is worn by the lens user and, as shown in FIG. 2, is placed on the cornea 10, the observation dye is injected into the tear fluid, and the tear fluid present between the lens and the cornea 10. Layer 11 is revealed. Then, the cornea is irradiated with measurement light and observed with a slit lamp microscope. At this time, the degree of penetration of tears into the bevel region 2 is checked based on an index provided on the lens surface. As a result, it is possible to quickly and accurately determine whether or not an appropriate tear fluid is exchanged in the bevel region 2 and whether or not a good wearing state is obtained.

  FIG. 4 is a photograph showing the wearing state of the contact lens of the present invention. In FIG. 4, 30 is a contact lens of the present invention, 31 is an index composed of grooves, and 32 is a cornea. In FIG. 4, the white annular portion 33 in the peripheral region of the contact lens 30 is tear fluid that has entered the bevel region. If the tear fluid 33 has entered the position of the index 31, it is determined that the tear fluid has entered the bevel region.

Next, a plurality of contact lenses provided with an index according to the present invention were manufactured, and it was tested to what extent the degree of penetration of tears into the bevel region could be checked using the index. In this test, as shown in Table 1, four types of contact lenses (evaluation lenses 1 to 4) were produced. The evaluation lenses 1 to 4 have base curves of 7.70 mm, 7.80 mm, 7.90 mm, and 8.00 mm, respectively, and the bevel area is positioned 0.5 to 0.7 mm inward from the lens edge. Provided.
Further, on the front surface of the lens, an index is provided at a position where a line extending in a direction perpendicular to the front curve from the transition portion from the lens central region to the bevel region on the rear surface of the lens intersects the front curve. For the evaluation lenses 1 and 2, as an index, a groove having a width of 0.03 mm and a depth of 0.02 mm is provided to form a circle. For the evaluation lens 3, the diameter is 0.02 mm and the depth is an index. Is provided at four locations with a dot-shaped groove of 0.01 mm, and for the evaluation lens 4, an arc groove having a width of 0.03 mm and a depth of 0.02 mm is spaced along the circumferential direction as an index. Provided.

Using a keratometry system PR7000 manufactured by Sun Contact Lens Co., Ltd., the lens wearer's corneal diameter, corneal weak principal meridian, corneal strong principal meridian, etc. are measured. Based on the curvature distribution of the entire cornea and aspheric coefficient data, The usefulness of the evaluation lens was confirmed.

Example 1
The lens wearer's cornea diameter is 11.6
The corneal weak main meridian (horizontal corneal radius of curvature) is 7.78 mm, the corneal strong main meridian (vertical corneal radius of curvature) is 7.65 mm, and the corneal radius of curvature approximates a conicoid quadratic curve. The aspherical coefficient obtained in this way was -0.25. The results were as follows.

Referring to Table 2, for evaluation lenses 2 to 4, the degree of entry of tears into the bevel region was at a level of entering “slightly in the center direction from the index”. The movement of these lenses on the cornea associated with blinking was “slightly meandering”, “meandering”, and “little”. Also, these lenses did not stand still in the central cornea.
On the other hand, for the evaluation lens 1, the degree of tears entering the bevel region was at a level of entering the “index part”. Moreover, the movement of the lens on the cornea associated with the blink did not meander, but moved smoothly in the vertical direction with the blink. In addition, the lens was stationary at the center of the cornea. As a result, in the evaluation lens 1, the lacrimal fluid appropriately entered the index position, and the overall determination could be determined as “appropriate”.

(Example 2)
The lens wearer has a corneal diameter of 11.6 mm, a weak main meridian of the cornea (horizontal corneal curvature radius) of 7.88 mm, a strong corneal main meridian (vertical corneal curvature radius) of 7.75 mm, and a corneal curvature. The aspherical coefficient obtained by approximating the radius to a conicoid quadratic curve was −0.34. The results were as follows.

With respect to the evaluation lenses 1 and 2, the degree of tears entering the bevel region was at a level of entering “slightly in the outer circumferential direction”. The movement of these lenses on the cornea accompanying blinking was “slightly fast”. In the evaluation lens 4, the degree of tears entering the bevel area was at a level of entering “slightly in the center direction from the index”. The movement of this lens on the cornea associated with blinking was “little”. These lenses did not rest in the central cornea.
On the other hand, for the evaluation lens 3, the degree of tears entering the bevel region was at a level of entering the “index part”. The lens moved smoothly on the cornea up and down with blinking. In addition, the lens was stationary at the center of the cornea. As a result, in the evaluation lens 3, the tear fluid appropriately entered the index position, and the overall determination could be determined as “appropriate”.

(Example 3)
The lens wearer's cornea diameter is 11.8 mm, the weak main meridian of the cornea (horizontal corneal radius of curvature) is 8.05 mm, the strong main meridian of the cornea (vertical corneal radius of curvature) is 7.96 mm, and the cornea The aspheric coefficient obtained by approximating the radius of curvature to a conicoid quadratic curve is -0.08. The results were as follows.

In the evaluation lens 1, the degree of tears entering the bevel region was at a level of entering “outer direction of 0.2 mm from the index”. In the evaluation lenses 2 to 3, the degree of penetration of tears into the bevel region was at a level of entering “slightly outward from the index”. Also, the movement of these lenses on the cornea associated with blinking was “slightly fast” to “fast”. In addition, these lenses did not rest in the central cornea.
On the other hand, with respect to the evaluation lens 4, the degree of tears entering the bevel region was at a level of entering the “index part”. The lens moved smoothly on the cornea up and down with blinking. In addition, the lens was stationary at the center of the cornea. As a result, in the evaluation lens 4, the lacrimal fluid appropriately entered the index position, and the overall determination could be determined as “appropriate”.

Example 4
The lens wearer has a corneal diameter of 11.7 mm, a weak main meridian of the cornea (horizontal corneal radius of curvature) of 7.83 mm, a strong corneal main meridian (vertical corneal radius of curvature) of 7.78 mm, and a corneal curvature. The aspheric coefficient obtained by approximating the radius to a conicoid quadratic curve was −0.15. The results were as follows.

In the evaluation lens 1, the degree of tears entering the bevel region was a level that entered the “slightly outer circumferential direction”. For the evaluation lenses 3 to 4, the degree of tears entering the bevel area was at a level of entering “slightly in the center direction from the index” and “about 0.2 mm in the center direction from the index”, respectively. In addition, the movement of these lenses on the cornea associated with blinking was “slightly less” to “less”. In addition, these lenses did not rest in the central cornea.
On the other hand, for the evaluation lens 2, the degree of tears entering the bevel region was at a level of entering the “index part”. The lens moved smoothly on the cornea up and down with blinking. In addition, the lens was stationary at the center of the cornea. As a result, in the evaluation lens 2, the tear fluid appropriately entered the index position, and the overall determination could be determined as “appropriate”.

1 is a plan view of a contact lens according to an embodiment of the present invention. FIG. 2 is a cross-sectional view along the diameter direction of the lens of FIG. 1 placed on the cornea. It is the top view which showed the modification of the parameter | index. It is a photograph which shows the wearing condition of the contact lens of this invention. It is sectional drawing along the diameter direction of the conventional hard contact lens set | placed on the cornea.

Explanation of symbols

1 Lens center area (Lens rear side)
2 Bevel area 3 Groove 4 Base curve 5 Lens center area (lens front side)
6 Front curve 7 Peripheral area 8 Transition part from lens central area to bevel area 9 Transition part from lens central area to peripheral area 10 Cornea 11 Tear layer

Claims (4)

In a contact lens having a lens rear surface composed of a circular lens central region and an annular bevel region provided outside the circular lens central region ,
In a region corresponding to the transition of the lens rear surface of the lens front surface, Bei example an indicator to check the entry of the tear with respect to the bevel region,
The area corresponding to the transition part of the rear surface of the lens on the front surface of the lens has a line extending from the transition part perpendicular to the front curve of the front surface of the lens and the front curve when the diametrical cross section of the lens is viewed. At the intersection,
The contact lens is characterized by comprising a groove having a width of 0.01 to 0.1 mm and a depth of 0.001 to 0.1 mm. In a contact lens having a lens rear surface composed of a circular lens central region and an annular bevel region provided outside the circular lens central region,
In the area corresponding to the transition part of the rear surface of the lens on the front surface of the lens, an index for checking the degree of tears entering the bevel area,
The area corresponding to the transition part of the rear surface of the lens on the front surface of the lens has a line extending from the transition part perpendicular to the front curve of the front surface of the lens and the front curve when the diametrical cross section of the lens is viewed. At the intersection,
The index is made of a belt-like printed thin film having a width of 0.01 to 0.1 mm.   3. The contact lens according to claim 1, wherein a plurality of the indicators are arranged at intervals from each other along a circumference having the center of the lens as the center.   The contact lens according to claim 1, wherein the index has a shape of a circle or a concentric circle whose center is the center of the lens.