Patent Publication Number: US-2022221736-A1

Title: Aspheric lens using e-value to control eye ball growth rate

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation-In-Part of co-pending application Ser. No. 16/707,519, filed on Dec. 9, 2019, which is a Continuation-In-Part of application Ser. No. 16/158,833, filed on Oct. 12, 2018, for which priority is claimed under 35 U.S.C. § 120, the entire contents of which are hereby incorporated by reference. 
     This application claims the priority benefit of Application No. 106217150 filed in Taiwan on Nov. 17, 2017. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an aspheric lens using E-value to control eyeball growth rate, especially the treatment zone of the lens uses a base curve with an eccentricity between −4˜4 to make the eccentricity of the image shell on the retina non-zero, to increase the peripheral defocus area of the image on the retina, thereby effectively controlling myopia or hyperopia. 
     2. Description of the Related Art 
     At present, the main methods of correcting refractive errors include wearing glasses, contact lenses, corneal myopia surgery or orthokeratology lenses. Each of the above methods has its advantages and disadvantages. Here, it is especially focus on orthokeratology lenses, where the orthokeratology lenses are made of high oxygen permeable rigid gas materials. When the lens is worn on the eyeball, a layer of unevenly distributed tear will be sandwiched between the lens and the outer surface of the cornea of the eyeball, and the epithelial cells can be squashed by the positive pressure exerted by the tear on the cornea. At the same time, if the wearer closes the eye, it will exert a certain pressure on the cornea by the weight of the eyelid and lens. If the wearing time is sufficient, the central curvature of the cornea can be gradually flattened and the central epithelial layer gradually thinned, so that the central cornea can be flattened, thereby reducing the refractive power of the cornea. In this way, the effect of correcting myopia and even returning to normal vision is achieved. 
     However, although general orthokeratology lenses can correct myopia, some people cannot effectively control the progression of myopia by wearing orthokeratology lenses, so that the power of myopia will continue to increase. Moreover, when the target power of the orthokeratology lens is low (between about −0.50 to −4.00 D), since the base curve of the orthokeratology lens is spherical, the space formed by the spherical base curve and the reverse curve on one side for the accumulation of tears will be insufficient, so that epithelial cells cannot be effectively squeezed, resulting in poor myopia control. How to solve the current problems and problems of wearing orthokeratology lenses is the direction that correlated industry in this field want to study and improve. 
     SUMMARY OF THE INVENTION 
     The present invention has been accomplished under the circumstances in view. It is therefore the main object of the present invention to provide an aspheric lens using E-value to control eyeball growth rate. The aspheric lens is an orthokeratology lens to be worn on the cornea surface of a preset eyeball. The surface of the orthokeratology lens is aspheric. The aspheric lens comprises a treatment zone through which light passes to image at the retina of the eyeball, and a positioning zone of the non-visual area outside the treatment zone. The treatment zone comprises a base curve, and a reverse curve formed on the outside of the base curve. The positioning zone comprises an alignment curve, and a peripheral curve located outside the alignment curve. The aspheric lens is provided with the alignment curve and the peripheral curve of the positioning zone from the outer side of the base curve and the reverse curve of the treatment zone to the outside in sequence. A center point is formed in the center of the base curve. The junction of the base curve and the reverse curve forms a first point of intersection. The junction of the reverse curve and the alignment curve forms a second point of intersection. The junction of the alignment curve and the peripheral curve forms a third point of intersection. The linear distance between the center point of the base curve and the cornea of the preset eyeball is between 9 μm˜21 μm. The linear distance between the first point of intersection and the cornea of the preset eyeball is between 89 μm˜189 μm. An electronic device is used to simulate wearing the orthokeratology lens on the cornea, and a calculation formula is used to calculate the tear volume between the cornea and the base curve and reverse curve of the preset orthokeratology lens. The calculation formula is tear volume=∫ 0   BCW/2 f1(x)dx+∫ BCW/2   (BCW+RCW)/2 f2(x)dx. In this way, it effectively controls myopia or hyperopia, to achieve the purpose of correcting myopia or hyperopia. 
     Another object of the present invention is that the eccentricity of the base curve of the aspheric lens is between −4˜4, and the eccentricity of the image shell of the image on the retina of the preset eyeball is non-zero. The reverse curve of the aspheric lens is aspherical. The linear distance between the second point of intersection between the reverse curve and the alignment curve and the cornea of the preset eyeball is between 15 μm˜25 μm. The third point of intersection between the alignment curve and the peripheral curve of the aspheric lens is in contact with the cornea surface of the preset eyeball. 
     Another object of the present invention is that the lens can be simulated on the cornea to be worn with the lens through an electronic device, and the calculation formula is used to calculate the tear volume between the base curve and the reverse curve of the cornea and the lens. Then adjust the eccentricity of the orthokeratology lens base curve to make the base curve aspherical, so that the tear volume between the orthokeratology lens and the cornea conforms to the tear volume required by the cornea shape to create peripheral defocusing. With this manufacturing method, the tear volume between the lens and the cornea can be easily matched to the required tear volume, to reduce manufacturing errors and achieve the purpose of improving product yield. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of the light path of the present invention. 
         FIG. 2  is a cross-sectional side view of the present invention. 
         FIG. 3  is a data diagram of the distance between the lens of the present invention and the cornea. 
         FIG. 4  is a flowchart of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1, 2 and 3 , as shown in the drawings, it can be clearly seen that the aspheric lens of the present invention uses E-value to control the eyeball growth rate. The lens  1  is an orthokeratology lens and the surface is aspheric. The lens  1  comprises a treatment zone  11  through which light passes to image at the retina  21  of the eyeball  2 , and a positioning zone  12  of the non-visual area outside the treatment zone  11 . 
     The treatment zone  11  comprises a base curve  111  (BC) whose eccentricity (E-value) can be between −4 and 4, and a reverse curve  112  (RC) formed on the outside of the base curve  111  to form a gap between the base curve  111  and the eyeball  2  for the accumulation of tears. 
     The positioning zone  12  comprises an alignment curve  121  that allows the lens  1  to be firmly fixed on the eyeball  2 , and a peripheral curve  122  (PC) located outside the alignment curve  121 . 
     The base curve  111  eccentricity of the treatment zone  11  of the lens  1  can be between −4 and 4, and when the eccentricity is between 0 and 1, the surface of the base curve  111  has an elliptical shape. 
     The above-mentioned lens  1  is provided with the alignment curve  121  and the peripheral curve  122  of the positioning zone  12  from the outer side of the base curve  111  and the reverse curve  112  of the treatment zone  11  to the outside in sequence. A center point  100  is formed in the center of the base curve  111 . The junction of the base curve  111  and the reverse curve  112  forms a first point of intersection  101 , the junction of the reverse curve  112  and the alignment curve  121  forms a second point of intersection  102 , and the junction of the alignment curve  121  and the peripheral curve  122  forms a third point of intersection  103 . The linear distance between the center point  100  of the base curve  111  and the cornea of the preset eyeball is between 9 μm˜21 μm. The linear distance between the first point of intersection  101  at the junction of the base curve ill and the reverse curve  112  and the cornea  22  of the preset eyeball  2  is between 89 μm˜189 μm. This way effectively controls myopia or hyperopia, to achieve the purpose of correcting myopia or hyperopia. The eccentricity of the base curve  111  of the treatment zone  11  of the aforementioned lens  1  can be between −4˜4, and the eccentricity of the image shell imaged on the retina  21  of the preset eyeball  2  is non-zero. The reverse curve  112  of the treatment zone  11  of the lens  1  is aspherical, and the linear distance between the second point of intersection  102  between the reverse curve  112  and the alignment curve  121  of the positioning zone  12  and the cornea  22  of the preset eyeball  2  can be between 15 μm˜25 μm. As for the third point of intersection  103  between the alignment curve  121  and the peripheral curve  122  of the positioning zone  12  of the lens  1  is in contact with the surface of the cornea  22  of the preset eyeball  2 . 
     The linear distance between the second point of intersection  102  between the reverse curve  112  of the treatment zone  11  and the alignment curve  121  of the positioning zone  12  of the lens  1  and the cornea  22  of the eyeball  2  is between 15 μm˜25 μm. Since the base curve  111  and the reverse curve  112  of the lens  1  are aspherical, the aspherical design can be used to ensure that the linear distance between the second point of intersection  102  and the cornea  22  of the eyeball  2  is between 15 μm˜25 μm, which can improve the manufacturing accuracy. Because the base curve  111  of the lens  1  is aspherical (eccentricity is non-zero), the eccentricity of the image shell  20  imaged on the retina  21  of the eyeball  2  can be made non-zero, to increase the peripheral defocus area of the image on the retina  21 , and then effectively control the speed of eye axial length change (lengthening or shortening), thereby effectively controlling myopia or hyperopia, thereby achieving the effect of correcting myopia or hyperopia. 
     Furthermore, the third point of intersection  103  between the alignment curve  121  and the peripheral curve  122  of the positioning zone  12  of the lens  1  is in contact with the surface of the cornea  22  of the eyeball  2 . Because the lens  1  is arc-shaped, the closer the lens  1  is to the outer periphery, the larger the circumference, so that when the third point of intersection  103  contacts the surface of the cornea  22  of the eyeball  2 , the contact part is the most, so that when the eyelid is closed on the lens  1 , the lens  1  is not prone to shaking, which can reduce the offset of the lens  1 , thereby improving the accuracy of squeezing, to surely squeeze the surface of the cornea  22 . 
     Furthermore, the preset curve of the base curve  111  of the treatment zone  11  of the lens  1  is greater than the horizontal curve of the cornea  22  of the eyeball  2  (that is, the curve of the base curve ill is flatter than the horizontal curve of the cornea  22 ). Since the curve of the base curve  11  is greater than the curve of the cornea  22 , when the lens  1  is worn on the eyeball  2 , the tear between the base curve  111  and the cornea  22  can generate a positive pressure on the epithelial cells of the cornea  22 . In addition, the reverse curve  112  of the lens  1  can store tears, and the negative pressure provided by the tears can achieve the effect of improving the positioning of the lens  1  on the eyeball  2 . 
     The peripheral curve  122  of the positioning zone  12  of the lens  1  preferably has a slightly raised edge design. It can squeeze the tears during blinking to promote the tear circulation inside the lens  1 , and the tear circulation can make the lens  1  and the cornea  22  of the eyeball  2  continue to lubricate and bring in oxygen, to improve the comfort of wearing and wearability. 
     In addition, an electronic device is used to simulate wearing the above-mentioned lens  1  on the cornea  22 , and a calculation formula is used to calculate the amount of tears between the cornea  22  and the base curve  111  and reverse curve  112  of the lens  1 . The formula is tear volume=∫ 0   BCW/2 f1(x)dx+∫ BCW/2   (BCW+RCW)/2 f2(x)dx. 
     When the present invention is used, the user can first put the lens  1  on the eyeball  2  and make the inner surface of the lens  1  contact the surface of the cornea  22  of the eyeball  2 . At this time, tears with uneven thickness will be generated between the inner surface of the lens  1  and the cornea  22 . When the user blinks or goes to bed at night to close the eyelid (not shown in the drawing), the eyelid will press against the outer surface of the lens  1 , and at the same time, the weight of the eyelid and the lens  1  will generate a positive pressure. The tear between the base curve  111  of the treatment zone  11  of the lens  1  and the cornea  22  exerts a positive pressure on the epithelial cells at the center of the surface of the cornea  22  of the eyeball  2 . The epithelial cells on the surface of the cornea  22  are squeezed by the tear, and the central curve gradually becomes relatively flat. Thereby, the central epithelial layer of the cornea  22  is thinned, thereby reducing the refractive power of the cornea  22 , so that the imaging point of the visual object is moved in the direction of the retina  21  of the eyeball  2 , thereby achieving the effect of reducing the power of myopia or eliminating the power of myopia. 
     Please refer to  FIGS. 1, 2, 3, and 4  again. It can be clearly seen from the drawings that the aspheric lens of the present invention uses E-value to control eyeball growth rate, and the lens  1  of the present invention is manufactured. It can include the following steps: 
     (A) Use a corneal inspection machine (not shown) to obtain the shape of the cornea  22  of the wearer&#39;s eyeball  2 , to know the amount of tears required for the shape of the cornea  22  to create peripheral defocusing. 
     (B) Use an electronic device (not shown) to simulate wearing the preset orthokeratology lens (not shown) on the cornea  22  and calculate the tear volume between the cornea  22  and the base curve and reverse curve of the preset orthokeratology lens. 
     (C) Perform a calibration operation on the preset orthokeratology lens. The calibration operation is to adjust the eccentricity (E-value) of the base curve of the preset orthokeratology lens so that the eccentricity of the base curve is non-zero, so that the base curve of the preset orthokeratology lens is aspherical. In this way, the eccentricity of the base curve can be adjusted to make the tear volume between the preset orthokeratology lens and the cornea  22  conform to the tear volume required for the shape of the cornea  22  to create peripheral defocusing. 
     (D) Use a lens manufacturing machine (not shown) to produce the lens  1  of the present invention according to the preset orthokeratology lens. 
     The corneal inspection machine in the above step (A) is a machine for detecting the diopter, shape, or radius of curvature of the cornea  22  of the eyeball  2 , such as Topography, Auto-K or any machine can inspect the Manifest refraction, Schirmer, Axial Length, or Corneal diameter, etc. 
     The tear volume required to create peripheral defocus in the above step (A) can be obtained through a wearing experiment (that is, subjects with different cornea  22  shapes wear the cornea orthokeratology lens used for the test to know the tear volume required to create peripheral defocusing, and then build a database to make the database contain the tear volume data required for various cornea  22  shapes to create peripheral defocus). 
     The electronic device of the above step (B) can be an electronic device with computing functions such as a desktop computer, a notebook computer or a tablet computer, and the electronic device can be installed with a preset cornea orthokeratology lens manufacturing software, which can be used to simulate wearing the preset orthokeratology lens on the cornea  22  and calculate the tear volume between the cornea  22  and the base curve and reverse curve of the preset orthokeratology lens. The formula can be: 
       tear volume=∫ 0   BCW/2   f 1( x ) dx+∫   BCW/2   (BCW+RCW)/2   f 2( x ) dx  
 
     In the above calculation formula, BCW is the width of the base curve of the preset orthokeratology lens, RCW is the width of the reverse curve of the preset orthokeratology lens, f1(x) is the inner surface of the base curve of the preset orthokeratology lens, and f2(x) is the inner surface of the reverse curve of the preset orthokeratology lens. 
     When the user wants to correct myopia or hyperopia (that is, the imaging distance of the eyeball  2  is too long or too short), the lens  1  can be worn on the eyeball  2  first, so that the light can pass through the treatment zone  11  of the lens  1 . When the light passes through the base curve  111  of the treatment zone  11 , the eccentricity of the base curve  111  can be between −4˜4, so that the image shell  20  imaged on the retina  21  is non-circular arc shape. The non-circular arc shape image shell  20  can increase the peripheral defocus area of the image on the retina  21  compared to the circular arc shape image shell, and due to the increase in the peripheral defocus area, compared to the general lens whose base curve is spherical, its myopia or hyperopia control effect is better. 
     Furthermore, when the above-mentioned user wants to correct myopia, the preferred eccentricity of the base curve  111  of the treatment zone  11  can be set between 0 and 1. When the light passes through the base curve  111 , the eccentricity of the image shell  20  imaged on the retina  21  can be between 0 and 1, which is a non-circular arc shape (ellipse). Compared with the preset spherical image shell A 0 , the non-circular arc shape image shell  20  can increase the peripheral defocus area on the peripheral out-of-focus image area  211  of the retina  21 , to have a better myopia control effect.