CN106842613A - soft contact lens - Google Patents

Abstract

The invention discloses a kind of soft corneal contact lens, including wearing rear surface and the preceding surface relative with rear surface on the tear layer on cornea surface for being covered in, wherein, preceding surface includes circular center arc area and the annular prevention and control arc area around center arc area, the negative focal power or zero focal power with the near vision power about equivalent with hyperphoria with fixed eyeballs are formed between center arc area and rear surface, positive focal power is incremented by by amount is smooth from inside to outside in prevention and control arc area, and the positive focal power total increment value in prevention and control arc area depends on the near vision power with hyperphoria with fixed eyeballs.

Description

soft contact lens

technical field

The invention relates to a soft corneal contact lens.

Background technique

The traditional soft contact lens is a kind of soft material lens worn on the cornea of the myopia patient to correct vision. It uses the negative focal power corresponding to the degree of myopia of the wearing eye to image the external objects in the On the retina of the wearing eye, the myopic patient can see the external objects clearly, thus correcting the myopia of the wearing eye. However, this traditional soft contact lens does not have the effect of controlling the development of myopia in adolescents.

In recent years, a kind of aspheric soft contact lens, also known as high definition soft contact lens (high definition SCL), has appeared. The advent of this aspheric soft contact lens is based on the following understanding: the front surface of the cornea is not a regular spherical surface, but an aspheric curved surface to a certain extent, that is, the central part of the cornea is the most curved, and the peripheral part gradually becomes curved. Flat, so the positive focal power is the largest in the center of the cornea, and the positive focal power decreases gradually as it shifts to the peripheral part of the cornea. The light emitted by the target object is first focused through the center of the cornea, and then focused after passing through the peripheral part of the cornea, which cannot simultaneously form a corresponding clear image on the fundus. Therefore, the aspherical shape of the cornea affects the visual acuity of the human eye and makes the vision of the eye slightly blurred, which is called the physiological aberration of the eye, as shown in Figure 1.

The design points of the aspheric soft contact lens are as follows. The shape of the optical zone on the front surface of the soft contact lens is designed as a reverse aspheric shape, that is, the curvature of the center of the front surface of the lens is the flattest, and it gradually becomes curved toward the periphery, so that The negative focal force is the largest at the center of the lens, and the negative focal force gradually decreases as it moves toward the peripheral part of the cornea, thereby offsetting the physiological aberration of the cornea and making the image of the target light close to the original true state, as shown in Figure 2. Aspherical soft contact lenses have been on the market for more than ten years. Clinical evaluations have recognized that this type of lens has the characteristics of clear vision, enhanced contrast sensitivity, and improved color vision. effect.

This is because the function of this kind of aspheric soft contact lens is limited to correcting the physiological aberration caused by the aspheric surface of the cornea, that is, the curvature of the front surface of the lens gradually changes from the center to the periphery. The curvature gradually flattens from the central part to the peripheral part by approximately the same amount. It is known that the physiological aberration of the cornea in the pupil area is only 0.25-1.00D. Assuming that the central curvature of the front surface of the lens is 42.00D, the curvature value of the edge of the optical zone is designed to be approximately 42.75D.

Another kind of contact lens opposite to soft contact lens is orthokeratology lens, also known as rigid gas permeable contact lens (Ortho-k lens) for orthokeratology. Orthokeratology lenses are made of rigid breathable polymer material, the main component is fluorinated silicone polymethyl methacrylate, the water content of this material is <1.0%, and the deformation strength is >70g. The inner surface is designed with four different curved surfaces, so that the lens can flatten and shape the cornea. After the lens is taken off, the myopia of the wearing eye can be corrected to a certain extent within a certain period of time. Lenses are usually worn at night, and the service life varies depending on the quality of maintenance, usually more than one year.

Figure 3 shows a coronal view of an orthokeratology lens. Figure 4 shows a sagittal view of an orthokeratology lens. As shown in Figures 3 and 4, the rear surface of the orthokeratology lens is sequentially designed into four parts from the center to the periphery, including a base arc, an inversion arc, a fitting arc, and a marginal arc. Contrary to the morphological law that the front surface of the cornea becomes flatter from the center to the periphery, that is, the base curve in the center of the lens is flatter than the center of the cornea, and the inversion curve around the base curve is to eliminate the flatness of the base curve compared with the cornea in the same area. Curved, the fitting arc surrounding the inversion arc has the same curvature as the cornea in the same area.

When the lens is attached to the cornea, because the fitting arc is the same as the curvature of the same area of the cornea, under the filling action of tears, the inner surface of the lens and the front surface of the cornea generate a relatively stable adhesion tension. At the same time, because the base arc of the central area of the lens is slightly flatter than the central area of the cornea, it has a flattening effect on the cornea, thereby achieving the effect of correcting myopia. The long-term accumulation of the flattening effect will locally maintain the center of the cornea In the flattened "shaping" state, after the lens is removed, the cornea will have a physical morphological "memory" effect. After the center of the cornea is flat, the positive focal force of the cornea is reduced. If the amount of flattening and shaping is equal to the degree of myopia of the wearing eye, the target light can be focused on the retina after entering the eye, thus making the myopia Get clear vision.

Under the flattening action of the lens, the cornea can produce a physical shape "memory" effect, but still maintain the biological shape constant properties, so the shaping effect of orthokeratology lenses is temporary and limited. After stopping wearing orthokeratology lenses, the myopia of the wearing eyes will return to the original level within a few days, so orthokeratology lenses cannot cure myopia.

The initial target of orthokeratology is to correct myopia. The lens is usually worn at night, and the night lens is centered and positioned stably. After taking off the lens during the day, the wearer does not need to wear any corrective glasses throughout the day. Maintain usable corrected vision as if without myopia. However, several years after orthokeratology lenses became popular, and after accumulating a large number of wearer samples, it was gradually found that the development of myopia in some cases of orthokeratology lenses has slowed down. For this unexpected discovery, a fitter made a lot of follow-up observations on the above clinical phenomena, and some literature compared and analyzed the degree of myopia development between wearing orthokeratology lenses and wearing ordinary soft contact lenses for several years , the results confirmed that after wearing orthokeratology lenses, there is a significant difference in the slowing down of the degree of myopia in the wearing eyes. There are also literatures that compare and analyze the degree of eye axial length extension between wearing orthokeratology lenses and wearing ordinary soft contact lenses for several years, and the results confirm that the development of eye axis length extension after wearing orthokeratology lenses There was a significant difference in slowing down.

It is an indisputable fact that after wearing orthokeratology lenses, the development of myopia in the wearing eyes slows down. As for its cause, recent studies believe that the occurrence and development of myopia is related to the blurred image of the retina. When the blurred image appears on the retina, it will affect the level of retinal neurotransmitters, and then affect the growth and development of the axial length of the eyeball. Due to the abnormal extension of the eye axis, the image of the external object will be focused in front of the retina, thus forming myopia.

There is a theory that after normal optical glasses correct myopia, the aspherical shape of the cornea makes the image in the peripheral area of the retina form behind the retina, so it is in a blurred state, which is called peripheral defocus. However, during the wearing process of orthokeratology lenses, since the inversion arc area does not contact the cornea, the tears contained in it will be discharged and form a negative pressure, which will increase the focus of the cornea in the same area and induce physiological aberrations of the cornea after shaping. After being corrected, the peripheral blurred image is reduced in the field of vision of the glasses, so that the development of myopia in the glasses is slowed down. Another theory is that after the usual optical glasses correct myopia, there is an abnormal adjustment lag when the wearing eye is gazing at the near target, that is, the wearing eye cannot mobilize enough adjustment when gazing at the near target, and the image in the central area of the retina is blurred and is blocked. called central defocus. However, in the modern living environment, the utilization rate of young people's near vision has exceeded 90%, which makes this pathogenic factor highlighted. However, during the wearing process of orthokeratology lenses, the focal increase in the reverse arc area makes the peripheral part of the retina have sufficient positive focal power, which not only effectively controls the peripheral defocus of the retinal image, but also makes the target image properly in front of the retina. The focal position of the eye is imaged, thus limiting the abnormal accommodation lag of the eye when fixating on near objects. The improvement of the image clarity in the center of the retina plays a vital role in slowing down the development of myopia in glasses-wearing eyes.

But orthokeratology lenses have the following disadvantages:

(1) Wearing orthokeratology lenses will put pressure on the central area of the cornea, resulting in pathological changes in the corneal epithelial cell layer and changes in the gaps between layers of the cornea, which may cause damage to the corneal epithelial barrier function and tear layer disorder. Epithelial damage, eye complications and long-term sequelae may occur due to wearing glasses.

(2) The rear surface of the orthokeratology lens only fits closely with the cornea in the area of the fitting arc, and its area only accounts for about 30% of the total area of the lens. Moreover, due to the individual differences in the shape of the aspheric surface and toric surface of the cornea, the posterior surface of the lens The contact surface between the surface and the cornea is smaller, so the fitting of the lens is not stable enough, and the accurate quantification of the fitting arc becomes the key to the success of the correction. The fitting arc parameters must be determined through time-consuming and repeated try-ins. The difficulty of fitting. It often induces insufficient myopia correction, irregular astigmatism, and deviating prisms. Therefore, the correction focus of orthokeratology lenses is only an approximate value. A certain percentage of wearers cannot succeed no matter how they modify the correction plan. Cases with myopia exceeding 5.00D are corrected The failure rate is even higher. Even after the successful correction of low myopia, it is unavoidable to change the amount of correction in the morning and afternoon due to the recovery of orthokeratology. In the evening, due to the enlarged pupil diameter, the depth of field of the light entering the eye is shortened, and the corrected vision is particularly blurred. Orthokeratology lens fitting technology is complicated and time-consuming, as well as insurmountable correction errors and correction failures, which have been criticized by fitters.

(3) Orthokeratology lenses are hard and the inner surface of the lens is not consistent with the shape of the cornea. As a result, many wearers cannot accept the foreign body sensation when wearing them for the first time. The sensory threshold of wearing the cornea increases, so that the cornea is in a state of sensory insensitivity for a long time, and the blinking decreases due to the numbness of the cornea, resulting in secondary dry eye symptoms. Wearers often stop wearing or give up treatment due to the unbearable pain of wearing glasses. Especially children audiences have acceptance bottlenecks and fears for orthokeratology lenses.

It can be seen that there is a need in the art for an improved technical solution that can prevent and control the development of myopia and overcome the shortcomings of orthokeratology lenses.

Contents of the invention

In order to solve the above technical problems, the technical solution of the present invention is proposed.

In one aspect of the present invention, a soft contact lens is provided, comprising a posterior surface for covering the tear layer of the corneal surface of the wearing eye and an anterior surface opposite to the posterior surface, wherein the anterior surface comprises a circular The central arc area and the ring-shaped prevention and control arc area surrounding the central arc area form a negative focal power or zero focal power approximately equal to the myopia power of the wearing eye between the central arc area and the rear surface, and the prevention and control arc area consists of The positive power increases smoothly from inside to outside, and the total incremental value of the positive power in the prevention and control arc area depends on the myopia power of the wearing eye.

The soft corneal contact lens of the present invention avoids various disadvantages of the orthokeratology lens, and retains the effect of the orthokeratology lens on preventing the development of myopia.

Description of drawings

Fig. 1 schematically shows the physiological aberrations of the cornea (prior art);

Fig. 2 schematically shows that the aspherical soft contact lens overcomes the physiological aberration of the cornea (prior art);

Fig. 3 schematically shows a coronal view of an orthokeratology lens (prior art);

Figure 4 schematically shows a sagittal view of an orthokeratology lens (prior art);

Figure 5 schematically shows the morphological changes of the anterior surface of the cornea after orthokeratology;

Fig. 6 schematically shows a physiological lens after orthokeratology analysis using parallel anterior movement of the posterior corneal surface;

Fig. 7 schematically shows the physiological lens after using the soft contact lens to simulate orthokeratology;

Fig. 8 schematically shows a panoramic view of the front surface of a soft contact lens according to an embodiment of the present invention;

Fig. 9 schematically shows a subdivision of the main arc areas of the front surface of the soft contact lens according to an embodiment of the present invention;

Fig. 10 schematically shows the radius of curvature of each sagittal arc in the main arc area of the soft contact lens according to an embodiment of the present invention;

Fig. 11 schematically shows an analysis diagram of the anterior effective arc transition rate of the soft contact lens according to an embodiment of the present invention.

detailed description

The formation of the basic idea of the invention was inspired by orthokeratology lenses. In view of the fact that a large number of clinical experiments have confirmed that orthokeratology lenses can prevent and control the occurrence and development of myopia to a certain extent, this invention intends to extract the effective elements shown in the corneal morphology of successful cases of orthokeratology lenses, and design them into soft contact lenses. The wearer does not need to modify the shape of the cornea to achieve the purpose of preventing and controlling myopia. Drawing on the experience that aspheric soft contact lenses cannot prevent and control myopia, we broke through the limitation of correcting corneal physiological aberrations when designing the lens surface. That is to say, the present invention uses soft contact lenses to simulate the corneal shape of successful cases of orthokeratology lenses, and retains the effective elements of myopia prevention and control in the corneal optical interface of successful cases of orthokeratology lenses.

The soft contact lens of the present invention can be made of, for example, soft high molecular polymer material, and its main component can be, for example, a hydrogel material such as polyhydroxyethyl methacrylate. The material is soft in texture and has a water content of 38-70%. The shape design of the inner surface of the lens can match the front surface of the cornea to the greatest extent, so the lens has no shaping effect on the cornea. In the state of wearing glasses, the lens can correct myopia. After taking off the lens, the shape of the cornea remains unchanged, and the wearing eye immediately returns to the original state of myopia. The wearing mode of the soft contact lens can be daily wearing, that is, wearing at non-sleeping time, without night wearing.

Myopia is manifested as an abnormal increase in positive focus of the eye. After wearing orthokeratology lenses, the central part of the cornea is flattened and shaped, thereby reducing the positive focus of the cornea and achieving the purpose of correcting myopia. Figure 5 shows the morphological changes of the anterior surface of the cornea after orthokeratology. It can be seen from the figure that the front surface of the cornea other than the geometric center of the cornea is pulled by the negative pressure of the lens reversal arc to form a focal increase zone with a width of about 2mm. valid element.

If the posterior surface of the cornea is moved forward in parallel, it can be seen that the corneal tissue between the anterior and posterior surfaces of the cornea has formed a very thin physiological lens with a special shape, as shown in Figure 6.

The present invention adopts the soft contact lens material to simulate the physiological lens formed by orthokeratology, and moves forward as a whole to the front of the cornea, thereby forming the myopia prevention and control soft contact lens of the present invention, as shown in FIG. 7 . Wearing the corneal contact lens can keep the shape of the cornea unchanged, and can also achieve the purpose of slowing down the development of myopia after orthokeratology.

Embodiments of the present invention are now described with reference to 8-10, wherein, Fig. 8 schematically shows a panoramic view of the front surface of a soft contact lens according to an embodiment of the present invention; The subdivision diagram of the main arc area of the front surface of the soft contact lens according to the embodiment of the invention; Fig. 10 schematically shows the sagittal arc radius diagram of the main arc area of the soft contact lens according to the embodiment of the invention .

As shown in FIGS. 8-10 , according to an embodiment of the present invention, a soft contact lens is provided that includes a posterior surface for overlying the tear layer of the corneal surface of the wearing eye and a rear surface opposite the posterior surface. The front surface, wherein the front surface includes a circular (that is, viewed as a circle from the front view) central arc area and a ring around the central arc area (that is, viewed as a ring from the front view) anti-arc area, the central arc area Negative focal power or zero focal power about the same amount as the myopic focal power of the wearing eye is formed between the back surface and the back surface, and the positive focal power of the prevention and control arc area increases smoothly gradually from the inside to the outside, and the total positive power of the prevention and control arc area The increment value depends on the myopic power of the wearing eye. The central arc area and the prevention and control arc area can be collectively referred to as the effective arc area.

The target corrected focal power specification of the soft contact lens determined by the focal power between the central arc region and the rear surface can be set as -1.00～-9.00D, and the step increment can be 0.25D, for example .

According to an embodiment of the present invention, the total incremental value of the positive power of the anti-arc zone may be 80%-110% of the myopic power of the wearing eye. For example, the total incremental value of the positive power of the arc prevention and control zone may be approximately equal to the myopic power of the wearing eye. For wearing eyes without myopia, the total increment value of the positive focal power in the prevention and control arc area can be about 0.75D, so that the occurrence of myopia can still be prevented.

According to an embodiment of the present invention, the central arc area may be a spherical arc, and its diameter may be about 2.0-4.0 mm, and the width of the anti-arc area may be about 2.0-2.4 mm. For example, the diameter of the central arc area may be about 3 mm, and the diameter of the anti-arc area may be about 2.1 mm.

According to an embodiment of the present invention, the arc prevention and control zone may further include a near-ring zone surrounding the central arc zone and a far-ring zone surrounding the near-ring zone, the width of the near-ring zone may be 0.8-1.2 mm, and the The width of the far ring area is about 1.2 mm, and the focal increase amount of the outer edge of the near ring area is 55% to 75% of the total incremental value of the positive focal power, and the focus increase amount of the outer edge of the far ring area is the positive power. 25% to 45% of the total incremental value of focal power. For example, the width of the near-ring area can be 1mm, and the focal increase amount of the outer edge of the near-ring area can be 65% of the total increase value of the positive focal power, and the focus increase amount of the outer edge of the far ring area can be the 35% of the total incremental value of the positive power mentioned above.

According to an embodiment of the present invention, the front surface may also include an annular release arc area with a width of about 0.8-1.2mm surrounding the prevention and control arc area, and the release arc area smoothly decreases from the inside to the outside in positive focus, which is used for digestion prevention and control The focal increase of the arc reduces the thickness of the edge of the lens. For example, the width of the release arc may be 0.8 mm.

The release arc area can have no optical effect, and is only used to release the focus increase of the arc prevention and control to achieve the purpose of reducing the edge thickness of the lens. The release arc area can decrease the focal increase amount of the prevention and control arc by about 75-85%, for example, it can decrease the focal increase amount of the prevention and control arc by 80%. Outside the release arc area, the focus increase amount of the remaining prevention and control arc areas can still be appropriately reduced to complete the curvature gradient difference between the release arc area and the above-mentioned front peripheral arc area.

According to an embodiment of the invention, the rear surface may comprise a centrally located circular (i.e. circular in front view) base arc and an annular (i.e. annular in front view) rear peripheral arc surrounding the base arc. , the base arc area can be a spherical arc surface, and its curvature can be one of several different curvatures selected from the range of about 8.1-8.9 mm according to the curvature of the wearing cornea. The area is flat 0.75-1.25D, and the front surface may also include a front peripheral arc surrounding the release arc, the arc power of the front peripheral arc may be the same as the rear peripheral arc. For example, the base arc area can be designed as two different values of curvature radius according to the curvature of the wearing cornea, which are 8.6mm and 8.3mm respectively. The selection of the radius of curvature of the base arc area can coincide with the front surface of the cornea for wearing.

According to an embodiment of the present invention, the diameter of the base arc may be 7.0-8.0 mm, the width of the rear peripheral arc may be 3.1-3.3 mm, and the width of the front peripheral arc may be 1.7-2.8 mm . For example, the diameter of the base arc may be 7.5 mm, the width of the rear peripheral arc may be 3.0 mm, and the width of the front peripheral arc may be 2.35 mm.

Thus, the total diameter of the chords of the soft contact lens can be obtained to be 13.2-14.6mm.

According to an embodiment of the present invention, the main matrix component of the lens material may be a hydrogel, such as polyhydroxyethyl methacrylate. The lens material may also include sodium hyaluronate and fluorinated silicone as auxiliary components, which function to increase the degree of moisture in the wearing eye and the level of corneal oxygen metabolism.

According to the known refractive index of the lens material, the target corrected focal power and the radius of curvature of the base arc of the rear surface of the lens, the parameters of the radius of curvature of the central arc of the front surface of the lens can be calculated. Calculated as follows.

(Formula 1)

In the formula, r ₁ is the radius of curvature parameter of the central arc area of the front surface, D is the target correction power, r ₂ is the radius of curvature parameter of the base arc area, and n is the refractive index of the material.

In addition, assuming that the prevention and control arc near the ring area completes X% of the total increase in focus of the prevention and control arc area (that is, the percentage of the outer edge of the prevention and control arc near the ring area to the total positive focus increment value of the prevention and control arc area is X%), according to the known refractive index of the lens material, the target corrected focal power and the radius of curvature parameter of the central arc area of the front surface, the value of the radius of curvature of the outer edge of the near ring area of the prevention and control arc can be calculated. Calculated as follows.

(Formula 2)

In the formula, r3 is the radius of curvature of the outer edge _of the control arc near the ring area.

Assuming that the prevention and control arc far ring area completes Y% of the total focus increase of the prevention and control arc area, according to the known refractive index of the lens material, the target correction power and the radius of curvature parameter of the outer edge of the near ring area, the distance outside the far ring area can be calculated. The radius of curvature of the edge. Calculated as follows.

(Formula 3)

In the formula, _r4 is the radius of curvature of the outer edge of the control arc far ring area.

Assuming that the total amount of focal increase in the prevention and control arc area is reduced by about Z% in the release arc area, the radius of curvature of the outer edge of the release arc area is calculated based on the known refractive index of the lens material, the target correction focal power, and the radius of curvature value of the edge of the far ring area value. Calculated as follows.

(Formula 4)

In the _formula , r5 is the radius of curvature of the outer edge of the release arc.

Fig. 8 shows the curvature gradient curve of an exemplary soft corneal lens lens front surface effective arc zone according to the above design according to an embodiment of the present invention, wherein the abscissa represents each position in the effective arc zone of the lens front surface The distance from the geometric center of the cornea, the ordinate indicates the rate of change of the curvature of the position relative to the base arc, where the curvature of the base arc is taken as the reference point 0, and the rate of change of the center of the effective arc area relative to the curvature of the base arc is 100%. It can be seen from the figure that as the distance from the geometric center of the cornea increases, the rate of change relative to the base arc curvature gradually decreases, and the rate of change relative to the base arc curvature is 0 at a distance of about 3.5 mm from the corneal geometric center. That is, it is equal to the curvature of the base arc. Of course, as those skilled in the art can understand, this curve only represents an exemplary and illustrative implementation of the geometric parameters of the soft contact lens lens of the present invention, rather than limiting the present invention.

The soft contact lens according to the embodiments of the present invention has at least the following advantages.

(1) Compared with the orthokeratology lens, the soft contact lens according to the embodiment of the present invention does not modify the corneal shape after wearing the lens, and avoids the pathological change of the corneal epithelial cell layer caused by the orthokeratology lens The changes in the gaps between the layers of the cornea and the cornea avoid the epithelial damage caused by the destruction of the corneal epithelial barrier function and the disorder of the tear layer. The present invention can be worn during the day, and does not cause the accumulation effect of corneal oxygen metabolism disorder induced by wearing orthokeratology lenses at night, resulting in corneal edema and thinning of the stroma layer. The invention successfully avoids eye complications which parents of orthokeratology lens wearers are most taboo about and possible long-term sequelae caused by wearing the lenses.

(2) According to the embodiment of the present invention, the rear surface of the lens of the soft contact lens is fully attached to the cornea, so there is no need to try it on, no need to re-examine, and the fitting is simple and time-saving. The amount is accurate, the clarity of vision remains unchanged in the morning and afternoon, the range of correction can reach 9.00D or more of myopia, and the possibility of correction failure is extremely small.

(3) The soft contact lens according to the embodiment of the present invention has soft lens material, strong plasticity, comfortable wearing without irritation, and no significant change in the sensory threshold of the cornea after wearing the lens, thus successfully avoiding the contact lens. Acceptance bottlenecks and fears of orthokeratology among children.

(4) The present invention uses soft contact lenses to simulate the corneal shape of the successful cases of orthokeratology lenses, and successfully retains the effective elements of myopia prevention and control in the corneal optical interface of the successful cases of orthokeratology lenses, thereby having the function of preventing and controlling myopia. control function. And because the correction amount is more accurate, the clear vision is more sustainable and stable, and there are fewer stoppages caused by complications of wearing glasses, so that the wearing eyes will feel less blurred images, and the effect of myopia prevention and control is more reliable.

The embodiments of the present invention have been described above with reference to the accompanying drawings. It should be noted that the above descriptions are exemplary and illustrative only, rather than limiting the present invention. For example, the shapes, dimensions, curves, etc. shown in the drawings and descriptions are merely exemplary and explanatory, and various changes and modifications are possible. For another example, terms in the specification and claims, such as the central arc area, the prevention and control arc area, the near ring area, the far ring area, the release arc area, the front peripheral arc area, the base arc area, the rear peripheral arc area, etc., It is only specified for the convenience of description, and does not constitute a limitation to the present invention. The concepts expressed by these terms could well be expressed using other terms. The protection scope of the present invention is limited only by the literal expressions of the appended claims and their equivalents.

Claims (13)

1. A soft contact lens, comprising a back surface for covering on the tear layer of the wearing corneal surface and an anterior surface opposite to the posterior surface, wherein the anterior surface comprises a circular central arc region and a surrounding center The ring-shaped prevention and control arc area of the arc area, the negative focal power or zero focal power approximately equal to the myopia focal power of the wearing eye is formed between the central arc area and the rear surface, and the positive focal power of the prevention and control arc area is gradually increased from the inside to the outside Smoothly increasing, the total incremental value of the positive focal power of the prevention and control arc area depends on the myopic focal power of the wearing eye. 2. The soft contact lens according to claim 1, wherein the total incremental value of the positive focal power of the prevention and control arc zone is 80%-110% of the myopic focal power of the wearing eye. 3. The soft contact lens according to claim 2, wherein the total increment value of the positive power of the anti-arc zone is approximately equal to the myopic power of the wearing eye. 4. The soft contact lens according to claim 1, wherein when the myopic power of the wearer's eye is 0 power, the total positive power increment of the anti-arc zone is about 0.75D. 5. The soft contact lens according to claim 1, wherein the diameter of the central arc is about 2.0-4.0mm, and the width of the anti-arc is about 2.0-2.4mm. 6. The soft contact lens of claim 5, wherein the diameter of the central arc is about 3 mm. 7. The soft contact lens according to claim 5, wherein the width of the anti-arc zone is about 2.1mm. 8. The soft contact lens according to claim 1, wherein the prevention and control arc zone comprises a near-ring zone around the central arc zone and a far-ring zone around the near-ring zone, and the width of the near-ring zone is 0.8- 1.2mm, the width of the far ring area is about 1.2mm, and the focus increase amount of the outer edge of the near ring area is 55% to 75% of the total increase value of the positive focal power, and the focus increase amount of the outer edge of the far ring area The amount is 25% to 45% of the total incremental value of the positive focal power. 9. The soft contact lens according to claim 8, wherein the width of the near-ring area is 1mm, and the focal increase amount of the outer edge of the near-ring area is 65% of the total incremental value of the positive focal power, far The focus increase amount at the outer edge of the ring area is 35% of the total increase value of the positive power. 10. The soft contact lens according to claim 1, wherein the front surface further includes an annular release arc area with a width of about 0.8-1.2 mm around the anti-arc area, and the release arc area is smooth from the inside to the outside. Decrease, which is used to eliminate the focal increase of arc prevention and control, thereby reducing the thickness of the edge of the lens. 11. The soft contact lens according to claim 5, wherein the posterior surface comprises a centrally located circular base arc and an annular rear peripheral arc surrounding the base arc, the base arc being a spherical arc with a curvature of According to the curvature of the wearing cornea is selected from one of several different curvatures in the range of about 8.1-8.9mm, the arc power of the posterior peripheral arc is flatter than that of the base arc by 0.75-1.25D, and the front surface also includes the arc around the The front peripheral arc of the release arc has the same arc focal power as the rear peripheral arc. 12. The soft contact lens according to claim 11, wherein the diameter of the base arc is 7.0-8.0 mm, the width of the rear peripheral arc is 3.1-3.3 mm, and the width of the front peripheral arc is 1.7-2.8mm. 13. The soft contact lens according to claim 1, wherein the main matrix component of the lens material is hydrogel, and the auxiliary components are sodium hyaluronate and fluorinated silicone.