CN212749433U

CN212749433U - Cornea shaping mirror

Info

Publication number: CN212749433U
Application number: CN202020791228.8U
Authority: CN
Inventors: 王曌; 解江冰
Original assignee: Abbott Beijing Medical Technology Co ltd
Current assignee: Abbott Beijing Medical Technology Co ltd; Eyebright Medical Technology Beijing Co Ltd
Priority date: 2020-05-13
Filing date: 2020-05-13
Publication date: 2021-03-19
Anticipated expiration: 2030-05-13

Abstract

The utility model provides a novel moulding mirror of base arc aspheric surface cornea for reduce the moulding back optics district spherical aberration of cornea, improve the visual quality after plucking the mirror, and increase the rise in reversal arc district, improve moulding efficiency and myopia control effect. The utility model discloses a moulding mirror of cornea includes the lens, its characterized in that, the rear surface in the base arc district of lens has the aspheric surface shape in the aspheric surface shape, the bending degree of central part is greater than and is located the bending degree of the peripheral part of central part periphery. That is, in the aspherical surface, the peripheral portion located on the outer periphery of the central portion is flatter than the central portion.

Description

Cornea shaping mirror

Technical Field

The utility model relates to an optical technical field is looked to the eye, in particular to wear to carry out moulding mirror of moulding cornea of people's eye cornea at night usually.

Background

The orthokeratology lens is a lens made of rigid air-permeable materials, is worn at night, and applies compression force through eyelid-lens-cornea to promote the migration/deformation of corneal epithelial cells and change the curvature radius of the cornea, thereby changing the refractive power of the cornea, temporarily changing the shape of the cornea and correcting ametropia.

Modern orthokeratology mirror is generally divided into four areas, namely a basal arc area (BC arc area), a reverse arc area (RC arc area), a fitting arc area (AC arc area) and a side arc area (PC arc area), and the design also comprises three areas, namely the basal arc area, the reverse arc area and a landing area. The basal arc area is the central area of the cornea, and the surface shape is relatively flat and is used for flattening the surface of the cornea; the reverse arc is steep and used for stabilizing the flattening effect of the base arc and ensuring a certain tear storage capacity; the positioning arc, also called fitting arc (or landing zone), is mainly used to stabilize the lens; the peripheral arc ensures the circulation of the cornea and the tear around the plastic lens. The base arc area of the traditional orthokeratology mirror is designed in a spherical surface mode and is only used for correcting myopia.

In the Chinese patent application CN201711278012.0, a corneal plastic lens with more than one curvature radius in the base arc region is proposed, which shapes the optical region of the cornea into several regions with different curvature radii, and simultaneously provides a plurality of focuses for the human eyes to correct the ametropia and simultaneously combine to correct the presbyopia. In the chinese patent application cn201510441201.x, a corneal shaping lens with a base arc having an aspheric design opposite to the aspheric direction of the cornea is mentioned, which is used for forming more optimized myopic peripheral defocus and playing a better role in myopia control. The chinese patent application CN201410039031.8 discloses a corneal plastic mirror with an aspheric outer surface in the optical area, which is used to solve the problem of optical interference when wearing the corneal plastic mirror at night.

SUMMERY OF THE UTILITY MODEL

After the existing orthokeratology mirror is worn, a patient has the problem of glare interference. The reason for generating the glare is relatively complex, and partly because the position of the reversal arc is too close to the pupil area, the curvature radius of the reversal arc is larger than that of the base arc, when the lens deviates or the diameter of the base arc area of the lens is too small, the large diopter of the reversal arc jumps to enter the pupil for imaging, the glare is formed, and the general patient is difficult to tolerate when the situation occurs, and the problem can be solved by enlarging the diameter of the base arc area or solving the deviation of the lens.

More generally, after a person wears the cornea shaping mirror, the spherical aberration of the optical area is increased, the cornea of the person originally has an aspheric surface which is flatter as the cornea goes to the periphery, the aberration compensation function is achieved, the difference of the whole eyeball tends to 0, or the aberration is in a smaller range, after shaping, the cornea is shaped into a spherical surface or an aspheric surface which is steeper than the spherical surface, the optical surface shape brings a large amount of positive spherical aberration to the cornea, the imaging quality of the optical area is affected, and patients complain that a luminous object (an eyeglass-off state) is in a light-ball shape at night, for example, when watching an elevator luminous button, the patient feels 'dazzling', namely, glare and halo caused by the fact that the difference of the whole eyeball is too large as the corneal spherical aberration is too large.

Table 1 shows the spherical aberration of the cornea at an aperture of 4mm before and after the orthokeratology lens is worn for orthokeratology, wherein the K value is the refractive power of the cornea and is expressed in D; the original corneal spherical aberration (first column of Table 1) was calculated using an aspheric coefficient of-0.29 for the corneal Q value as an example; spherical cornea (second column of table 1) refers to the shape of the cornea after being shaped by a common orthokeratology mirror; a steep aspheric surface (third column of table 1) is after the cornea is shaped into a steep aspheric surface as described in patent 201510441201.X, respectively. It can be seen that the wearing of the orthokeratology lens risks increasing the corneal spherical aberration of the patient. Given the natural vision clarity habit that has developed in adults, this optical disturbance generally has a greater effect on adults and, as such, has affected the popularity of orthokeratology lenses in adults.

TABLE 1 corneal spherical aberration contrast before and after wearing a corneal plastic lens (unit μm)

Value of K	Spherical aberration of natural cornea	Spherical aberration of spherical cornea	Steep aspheric surface
				40.0D	0.02	0.05	0.08
43.0D	0.03	0.07	0.10
				46.0D	0.04	0.08	0.12

In view of this, an object of the present invention is to provide a novel orthokeratology mirror with an aspheric base arc region, which is used to reduce the spherical aberration of the optical region after orthokeratology and improve the visual quality after picking the mirror. Additionally, the aspheric surface of the base arc curve can be designed to increase the rise of the reversal arc area, so that the shaping efficiency is improved, the peripheral defocusing amount is increased, and the myopia control effect is improved.

In order to achieve the above object, the orthokeratology mirror of the present invention is an orthokeratology mirror, which comprises a mirror plate, characterized in that the back surface of the base curve region of the mirror plate has an aspherical shape in which the degree of curvature of the central portion is larger than the degree of curvature of the peripheral portion located at the periphery of the central portion. That is, in the aspherical shape, the peripheral portion located on the outer periphery of the central portion is flatter than the central portion.

Typically, the degree of curvature is measured in terms of the equivalent radius of curvature, specifically, in the aspherical shape, the equivalent radius of curvature of the central portion is smaller than the equivalent radius of curvature of the peripheral portions located at the periphery of the central portion.

With the above configuration, since the back surface of the base curve region of the lens has an aspheric shape in which the equivalent radius of curvature of the central portion is smaller than that of the peripheral portion located at the outer periphery of the central portion, as demonstrated in the following embodiments, the spherical aberration of the optical region of the rear film after shaping can be reduced, the visual quality can be improved, and the bad visual effects such as glare and halo can be reduced.

In addition, by adopting the structure, the rise difference of the reversal arc area can be increased, and the shaping efficiency is improved. The rise difference of the inversion arc region refers to the difference between the rise of the starting point and the rise of the end point of the inversion arc, wherein the starting point is the end point of the base arc region, namely the rise of the edge position of the base arc region, and the end point is the starting point of the positioning arc (adaptive arc). The sagittal height refers to the height difference between the position of the point on the lens and the vertex of the keratoplasty lens (O in figure 3), and the sagittal height of the edge position of the base arc zone is schematically shown as 05 in figure 3.

Moreover, by adopting the structure, the peripheral defocusing amount of the 'bull' eye ring can be improved, and the myopia control effect is improved. Specifically, the orthokeratology lens is widely applied to myopia control of teenagers, the mainstream theory in control is myopia and peripheral defocus, and a large number of researches suggest that after the orthokeratology lens is shaped, a cornea with an inverted arc can bring a large amount of peripheral defocus to eyes of people after the cornea is shaped, and the area is called as a 'bull' eye ring. The base arc aspheric surface design can increase the rise difference of the reversal arc area, the reversal arc area is steeper than that of the conventional spherical lens, and the peripheral defocusing amount formed by the bullseye is larger, so that a better effect can be brought to myopia control.

As an alternative, the surface shape expression of the aspheric shape is:

wherein Z (y) is an expression of a curve of an aspheric generatrix of the base arc area on a YZ plane, c is the curvature of a base sphere of the base arc area, and y isThe vertical distance from any point on the curve to the abscissa axis (Z), Q is the aspheric coefficient, A_2iEach point on the aspherical shape is obtained from the curve by rotation about the abscissa axis (Z) for a high order coefficient of the aspherical surface, and the aspherical surface takes a Q value or the Q value is used in combination with a high order coefficient.

As an alternative, the amplitude of the aspheric surface is defined by a scaling factor η of the equivalent radius of curvature. Eta is different aperture d_m、d_nA ratio of equivalent radii of curvature r of wherein m > n:

the calculation method of the equivalent curvature radius is as follows:

wherein d is_mFor measuring the aperture, i.e. the aperture at a certain point M, h_mIs the rise of the M point, i.e. the height difference between the M point and the vertex of the aspheric surface, r_mIs the equivalent radius of curvature of point M.

Optionally, when m is 5 and n is 2, the scale factor η of the equivalent curvature radius of the aspheric surface is 1.01 to 1.027, 1.001 to 1.019, or 1.003 to 1.014.

As an optional mode, the equivalent curvature radius within 3mm of the center of the base arc area is 7.0-10.0 mm or 7.5-9.93 mm.

As an optional mode, the base arc area is positioned in the center of the lens and is adjacent to the reversal arc area, and the diameter of the base arc area is 4.5-8.0 mm, 5.0-7.0 mm or 5.0-6.5 mm.

As an optional mode, the reversal arc area is adjacent to the base arc area, and the diameter width is 0.3-2.0 mm, 0.4-1.5 mm, or 0.5-1.0 mm.

As an optional mode, the arc-shaped structure is provided with a matching arc area, the matching arc area is adjacent to the reversal arc area, and the diameter width is 0.3-2.0 mm, 0.4-1.5 mm or 0.5-1.0 mm.

Optionally, the orthokeratology lens has a tilted area adjacent to the adaptive arc area and located at the outermost periphery of the lens, and the radial width is 0.4-1.0 mm or 0.4-0.7 mm.

Definition of terms

The following definitions apply to terms used in this specification unless specifically stated otherwise.

The basal arc zone (BC) is positioned at the most central part of the cornea shaping mirror and is the inner surface of the optical zone and is used for pressing the front surface of the cornea and shaping the front surface of the cornea into the shape, and the area of the shaped cornea is the optical zone and plays a role in optical imaging.

The reverse arc area (RC) is a second area closely connected with the base arc area, and plays a role in connecting the base arc area and the adaptive arc area, forming a gap between the orthokeratology lens and the front surface of the cornea, and playing a role in storing tears and promoting the circulation of the tears.

The adaptive arc Area (AC) is also called a positioning arc area, a matching arc area and the like, is close to the reversal arc area, and the area is matched with the shape of the cornea to play a role in positioning.

The side arc area (PC) is optional, is positioned at the outermost edge of the orthokeratology lens, is tightly connected with the adaptive arc area, is generally flatter than the adaptive arc area, and forms a certain tilting angle with the surface of the cornea, thereby ensuring the exchange and the circulation of tears and oxygen around the cornea and the orthokeratology lens.

Moreover, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of inconsistency, the present specification and the definitions included therein shall control.

Drawings

Fig. 1 is a diagram of an expression for a curve representing an aspherical bus of a base arc region on a YZ plane, where a is a spherical bus and B is an aspherical bus.

FIG. 2 shows the equivalent curvature radius calculation method, where M is any point on the aspheric surface, O is the aspheric surface vertex, and r is_mIs an equivalent radius of curvature, d_mIs the diameter of the point M, h_mIs the rise of the point M, i.e. MThe vertical distance of the point from the vertex.

Fig. 3 is a schematic diagram of the inner surface of the orthokeratology lens, wherein O is the vertex of the inner surface of the lens, 01 'is the base arc of the sphere, 01 is the base arc of the aspheric surface, 02' is the inverse arc of the sphere, 02 is the inverse arc of the aspheric surface, 03 is the fitting arc, 04 is the edge arc, and 05 is the edge rise of the base arc.

Detailed Description

Next, specific embodiments of the present invention will be described in detail.

The orthokeratology lens in the embodiment is made of a hard high oxygen permeable material, has a front surface and a back surface, wherein the back surface refers to a surface which is in contact with a cornea when being worn, has an inverse geometric design, and at least comprises a base arc area which compresses the cornea, the base arc area is positioned in the center of the orthokeratology lens, the diameter of the base arc area is 4.5-8.0 mm, preferably 5.0-7.0 mm, and more preferably 5.0-6.5 mm; a tear-containing zone (inverted arc zone) adjacent to the base arc zone and having a diameter width of between 0.3 and 2.0mm, preferably between 0.4 and 1.5mm, more preferably between 0.5 and 1.0 mm; a positioning arc area (adaptive arc area) which is contacted with the cornea and has a positioning function, is adjacent to the reversal arc area, and has a diameter width of 0.3-2.0 mm, preferably 0.4-1.5 mm, more preferably 0.5-1.0 mm; and the edge arc area is adjacent to the adaptive arc area, is positioned at the outermost periphery of the lens, has the diameter width of 0.4-1.0 mm, preferably 0.4-0.7 mm, and has the shape consistent with that of the positioning arc area under certain conditions without forming obvious distinction.

The base arc area of the cornea shaping mirror is an aspheric surface, and in the aspheric surface, the equivalent curvature radius of the peripheral part is larger than that of the central part. And the aspherical surface has a flatter curvature toward the periphery than the spherical surface. In other words, in the orthokeratology mirror of the present embodiment, the central portion is curved to a greater extent than the peripheral portion located at the outer periphery of the central portion in the aspherical surface of the base curve region. By aspheric is meant herein that the curved surface shape of the base curve region is not spherical.

In the present embodiment, the aspherical surface adopts the following surface shape expression:

wherein Z (y) is an expression of a curve of an aspheric generatrix of the base arc region on a YZ plane, as shown in FIG. 1, c is a curvature of a base sphere of the base arc region, y is a vertical distance of any point on the curve from an abscissa axis (Z), Q is an aspheric coefficient, A_2iEach point on the aspherical surface shape is obtained from the curve by forming axial symmetry by rotating around an abscissa axis (Z) for aspherical high-order term coefficients.

The above expression is a typical aspherical expression in the optical field, and when an aspherical shape is specifically designed using the expression, a Q value, or a coefficient of a high-order term, or a Q value and a coefficient of a high-order term may be used in combination. That is, the Q value and the high-order coefficient may be zero.

The equivalent curvature radius within 3mm of the center of the base arc area (under small aperture) is 7.0-10.0 mm, preferably 7.5-9.93 mm.

The amplitude (degree of deviation from the basic sphere) of the aspheric surface is defined by a scale factor eta of the equivalent curvature radius, eta being different aperture diameters d_m、d_nA ratio of equivalent radii of curvature r of wherein m > n:

for spherical surfaces, η ═ 1; for aspheric surfaces with flatter periphery than center, η > 1; for aspheric surfaces with steeper perimeter than center, η < 1.

Further, when m is 5 and n is 2, the scale factor η of the equivalent curvature radius of the aspherical surface is 1.01 to 1.027, preferably 1.001 to 1.019, and more preferably 1.003 to 1.014.

As an example, the equivalent radius of curvature is calculated as follows:

wherein d is_mFor measuring the aperture, M is the aperture d_mPoint of (d), h_mIs the rise of the M point, i.e. the height difference between the M point and the vertex of the aspheric surface, r_mIs the equivalent radius of curvature of point M.

Table 2 is a partial example, wherein base curve K represents the radius of curvature of the base curve in converted to corneal power in units of D, which is related to the radius of curvature of the base curve zone:

wherein, R is the curvature radius of the basic sphere of the base arc area. From this, the radius of the base spherical surface of the base arc zone is obtained from the diopter of the cornea.

Wherein, Q, A₂、A₄、A₆The parameters of the inverse arc, the adaptive arc and the side arc are the diameter width (mm)/curvature radius (mm).

TABLE 2 examples

Table 3 shows the scaling factor η of the equivalent radius of curvature of the base arc region of the example shown in table 2, where m is 5 and n is 2, and in this case, the scaling factor η of the equivalent radius of curvature of the aspheric surface is 1.01 to 1.027, preferably 1.001 to 1.019, and more preferably 1.003 to 1.014.

TABLE 3 scaling factor eta of equivalent radius of curvature of base-arc zone

Example number	Scale factor eta	Example number	Scale factor eta
				1	1.002	10	1.003
2	1.004	11	1.013
				3	1.007	12	1.027
4	1.009	13	1.014
				5	1.011	14	1.019
6	1.015	15	1.008
				7	1.019	16	1.009
8	1.021	17	1.007
				9	1.001	18	1.004

Table 4 shows the corneal spherical aberration (in μm), base arc edge rise (in μm) at 4mm diameter after corneal sculpting for the examples described in Table 2, in comparison to a conventional spherical sculpting mirror. Wherein the radius of curvature of the ordinary spherical surface is the same as the radius of curvature of the base spherical surface of the aspherical surface.

TABLE 4 spherical aberration, base arc edge rise contrast

Therefore, the above-mentioned base arc aspheric surface design of the orthokeratology mirror of the present embodiment can provide at least three technical effects:

(1) the spherical aberration of the optical area of the film after shaping can be reduced, the visual quality is improved, and the bad visual effects such as glare, halation and the like are reduced.

(2) The rise difference of the reversal arc area can be increased, and the shaping efficiency is improved. The rise difference of the inversion arc region refers to the difference between the rise of the starting point and the rise of the end point of the inversion arc, wherein the starting point is the end point of the base arc region, namely the rise of the edge position of the base arc region, and the end point is the starting point of the positioning arc (adaptive arc). The sagittal height refers to the height difference between the position of the point on the lens and the vertex of the keratoplasty lens (O in figure 3), and the sagittal height of the edge position of the base arc zone is schematically shown as 05 in figure 3.

As can be seen from Table 3, the rise of the base arc aspheric surface design at the base arc edge is 0.9-43.1 μm smaller than that of the common spherical base arc design, and the end rise of the inversion arc is unchanged, so that the rise difference of the inversion arc is increased. The rise difference of the reversal arc determines the shaping efficiency, and under the condition that other parameters are consistent, the bigger the rise difference of the reversal arc is, the faster the shaping speed is. For example, in example 3 shown in table 2, if the parameters of the other arc regions are consistent, the corneal plastic lens is designed according to the corresponding spherical base arc, and the myopia decreasing rate is about 0.75-1.0D in 30 minutes, but if the base arc is designed according to the aspheric surface, the myopia decreasing rate can reach 1.0-1.5D in 30 minutes, and the difference of the decreasing rate is larger when the corneal plastic lens is worn at night or more.

(3) The defocusing amount of the periphery of the 'bull' eye ring is increased, and the myopia control effect is improved. Specifically, the orthokeratology lens is widely applied to myopia control of teenagers, the mainstream theory in control is myopia and peripheral defocus, and a large number of researches suggest that after the orthokeratology lens is shaped, a cornea with an inverted arc can bring a large amount of peripheral defocus to eyes of people after the cornea is shaped, and the area is called as a 'bull' eye ring. The base arc aspheric surface design can increase the rise difference of the reversal arc area, the reversal arc area is steeper than that of the conventional spherical lens, and the peripheral defocusing amount formed by the bullseye is larger, so that a better effect can be brought to myopia control.

In the embodiment, the base arc area is an aspheric surface using the above expression, as a comparative example, if the base arc area is designed as a spherical surface with a curvature varying in a stepwise manner, since the stepwise spherical surface is also a spherical surface with spherical aberration, the glare problem caused by the spherical aberration cannot be solved, and the problem of image jump and aperture caused by the connection of each section of spherical surface is also solved, so the technical problem of the present invention cannot be solved by the stepwise spherical surface.

The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A orthokeratology lens comprising a lens, wherein a posterior surface of a base curve region of the lens has an aspheric shape in which a central portion is curved to a greater extent than a peripheral portion located at a periphery of the central portion.

2. The orthokeratology mirror of claim 1, wherein in the aspheric shape, an equivalent radius of curvature of a central portion is smaller than an equivalent radius of curvature of a peripheral portion located at a periphery of the central portion.

3. The orthokeratology mirror of claim 1 or 2, wherein the aspheric shape has a surface shape expressed by:

wherein Z (y) is an expression of a curve of an aspheric generatrix of the base arc area on a YZ plane, c is the curvature of a base sphere of the base arc area, y is the vertical distance of any point on the curve from an abscissa axis (Z), Q is an aspheric coefficient, A is_2iEach point on the aspherical shape is obtained from the curve by rotating around the abscissa axis (Z), which is an aspherical high-order term coefficient.

4. According to claim 1 or 2The orthokeratology mirror is characterized in that the amplitude of the aspheric surface is defined by a scale factor eta of an equivalent curvature radius, wherein eta is different aperture diameters d_m、d_nA ratio of equivalent radii of curvature r where m > n, the scaling factor η satisfying the following relationship:

the calculation method of the equivalent curvature radius is as follows:

wherein r is_mIs the equivalent radius of curvature of point M, d_mIs the aperture at M point, h_mThe rise of the M point is the height difference of the aspheric surface between the M point and the vertex.

5. The orthokeratology mirror of claim 4,

when m is 5 and n is 2, the scale factor eta of the equivalent curvature radius of the aspheric surface is 1.01-1.027, 1.001-1.019 or 1.003-1.014.

6. The orthokeratology mirror of claim 1 or 2,

the equivalent curvature radius within 3mm of the center of the base arc area is 7.0-10.0 mm or 7.5-9.93 mm.

7. The orthokeratology mirror of claim 1 or 2,

the base arc area is located in the center of the lens and adjacent to the reverse arc area, and the diameter of the base arc area is 4.5-8.0 mm, 5.0-7.0 mm or 5.0-6.5 mm.

8. The orthokeratology mirror of claim 7,

the reversal arc area is adjacent to the base arc area, and the diameter width is 0.3-2.0 mm, 0.4-1.5 mm or 0.5-1.0 mm.

9. The orthokeratology mirror of claim 8,

the arc-matching area is adjacent to the reverse arc area, and the diameter width is 0.3-2.0 mm, 0.4-1.5 mm or 0.5-1.0 mm.

10. The orthokeratology lens of claim 9, having a peripheral zone adjacent to the compliant arc zone and located at the outermost periphery of the lens, and having a radial width of 0.4-1.0 mm or 0.4-0.7 mm.