CN114779497B - Scleral contact lens based on phase modulation technology - Google Patents
Scleral contact lens based on phase modulation technology Download PDFInfo
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- CN114779497B CN114779497B CN202210500567.XA CN202210500567A CN114779497B CN 114779497 B CN114779497 B CN 114779497B CN 202210500567 A CN202210500567 A CN 202210500567A CN 114779497 B CN114779497 B CN 114779497B
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- 210000004087 cornea Anatomy 0.000 claims abstract description 70
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- 230000004075 alteration Effects 0.000 claims abstract description 33
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- 238000013461 design Methods 0.000 abstract description 11
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Classifications
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- G—PHYSICS
- G02—OPTICS
- G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
- G02C7/00—Optical parts
- G02C7/02—Lenses; Lens systems ; Methods of designing lenses
- G02C7/04—Contact lenses for the eyes
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/0012—Optical design, e.g. procedures, algorithms, optimisation routines
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/0025—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for optical correction, e.g. distorsion, aberration
-
- G—PHYSICS
- G02—OPTICS
- G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
- G02C7/00—Optical parts
- G02C7/02—Lenses; Lens systems ; Methods of designing lenses
- G02C7/024—Methods of designing ophthalmic lenses
- G02C7/027—Methods of designing ophthalmic lenses considering wearer's parameters
-
- G—PHYSICS
- G02—OPTICS
- G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
- G02C7/00—Optical parts
- G02C7/02—Lenses; Lens systems ; Methods of designing lenses
- G02C7/04—Contact lenses for the eyes
- G02C7/047—Contact lens fitting; Contact lenses for orthokeratology; Contact lenses for specially shaped corneae
-
- G—PHYSICS
- G02—OPTICS
- G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
- G02C2202/00—Generic optical aspects applicable to one or more of the subgroups of G02C7/00
- G02C2202/22—Correction of higher order and chromatic aberrations, wave front measurement and calculation
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- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Ophthalmology & Optometry (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- General Health & Medical Sciences (AREA)
- Prostheses (AREA)
Abstract
According to the sclera contact lens based on the phase modulation technology, the modulation/demodulation phase is superposed on the optical surface of the front surface of the sclera contact lens, so that the wavefront aberration of the whole eye is modulated in a personalized way, the requirements of design on the wavefront aberration of the human eye are met, various wavefront aberrations of the front surface of the cornea of a patient are accurately compensated, and the vision level and the vision quality of the patient are greatly improved.
Description
Technical Field
The invention relates to the technical field of scleral contact lenses, in particular to a scleral contact lens based on a phase modulation technology.
Background
Scleral lenses are specially designed rigid gas permeable contact lenses, which are named after landing on the scleral area across the entire cornea because of the large diameter of the lens, without contact with the cornea, and are filled with preservative-free saline between the lens and the cornea. The large diameter contact lens positions the lens beyond the limbus of the cornea, making it considered the best way to correct irregular cornea patient vision, with the cornea being truly clear of the lens by wearing the lens sheet, without any mechanical friction, avoiding as much as possible any contact between the lens and the cornea, so that the lens spans the cornea like a bridge, as shown in fig. 1. Technically, these lenses are not contact lenses, at least not in contact with the corneal surface, and the comfort of the cornea is greatly improved, which is one of the greatest advantages of large diameter contact lenses.
In recent years, scleral lenses are becoming popular in Europe and America, and have certain advantages for refractive correction, irregular cornea and dry eye treatment due to their personalized designs. The diameter classification of the scleral lens can be classified into a cornucopia (diameter 12.5mm-15mm, contact part cornea), a mini scleral lens (diameter 15mm-18mm, full contact sclera), a full scleral lens (18 mm-25mm, full contact sclera), and a superior oxygen permeability and visual quality due to a generally small tear water storage amount of the mini scleral lens, and a superior corneal vertex gap, which can reduce mechanical friction on the central cornea.
The scleral lens adopts a gas-permeable rigid gas-permeable scleral contact lens material, namely, the material with different oxygen permeability coefficients is gradually improved and formed through an RGP material with high oxygen permeability. Current lens materials come primarily from BOSTON, menicon and CONTAMAC. The BOSTON material is the material with the greatest global use amount, most common use and most people, has higher oxygen permeability and wettability and good comfort level, wherein the BOSTON XO2 material has a wetting angle 38, an oxygen permeability coefficient of 141, a higher Dk value, good dimensional stability and processability, and has been applied to hard breathable contact lenses for cornea shaping, the safety and the effectiveness of the hard breathable contact lenses have been verified, and the high oxygen permeability and balanced processability of the hard breathable contact lenses are ideal materials for preparing scleral lenses. Scleral lenses require the use of high Dk materials and the tear fluid in the lens and cornea gap should not be excessive to prevent hypoxia. Studies have shown that no current study demonstrates that wearing modern scleral lenses can cause corneal hypoxia.
The clinical application of the scleral lens generally adopts a test-wearing piece, and adopts a test-wearing evaluation technology, and the main test-matching process is as follows: first, a corneoscleral topography was performed, slit lamp examination, and OCT anterior ocular segment examination. Obtaining the sagittal height from the corneal vertex to the landing zone and the corresponding sagittal height difference, and selecting a proper fitting piece for fitting evaluation; before wearing, the lens is held by a suction rod, physiological saline and sodium fluorescein are dripped into the lens, a patient is ordered to vertically see the lower head of the patient to the ground, the upper eyelid and the lower eyelid are strutted by the hands of the patient as much as possible to expose eyeballs, a doctor helps the patient to wear the lens, and whether air bubbles exist under the lens or not is observed, and if the air bubbles exist, the patient needs to take out the lens and wear the lens again. When the scleral lens is worn, the lens mobility is almost zero, and tear exchange is almost not caused. The ideal apical tear film gap is around 300 microns, with slight depression on the lens edge landing on the sclera, and the tear film thickness is significantly reduced (120-170 microns) after wear, so the fit assessment is performed half an hour after wear. Tear thickness between the lens and cornea was assessed by using a slit lamp and observing the tear thickness under the lens at 45 degrees using optical sectioning (optionally using fluorescent staining). The observation of the limbus under the slit lamp is to fill the limbus with 360-degree fluorescence, so that the direct contact between the lens and the limbus is avoided, and the edge of the lens has no pressure on the bulbar conjunctiva blood vessel. The limbal part is important for corneal health, and in particular stem cells are responsible for the production of new epithelial cells that are scattered throughout the cornea. Tears between the lens and the limbal part are very important for fragile stem cells of the limbal part, a space of about 100 microns is ensured as much as possible in the process of testing, OCT is recommended to be used as an auxiliary tool in the process of testing, the tear thickness which should be reserved at each position is accurately estimated from the central vertex to the limbal part, and the accuracy of testing and matching is improved.
It is also important to evaluate the pressure exerted by the lens positioning arc on the bulbar conjunctiva. If the localized area is too tightly pressed against the conjunctiva, blood in the region of the conjunctival pressure will not pass through the blood vessel, causing the subconjunctival blood vessel under the lens to whiten. In addition, scleral lenses also require a rocker to assist in tear circulation. However, the warping angle is not too high, and the too high warping angle can increase foreign body sensation, so that the wearer is easy to feel uncomfortable, and wearing comfort is affected. The tilt angle can be adjusted by changing the location area angle. Finally, subjective refraction and vision inspection after wearing the glasses are carried out, and the diopter of the lenses is determined.
In general, hard scleral contact lenses have the following unique advantages: (1) The high oxygen permeability ensures that the surface of the eye obtains sufficient oxygen, thereby greatly reducing complications compared with the common soft lens, and being one of the safest contact lenses to be worn at present; (2) The forming effect is good, the optical performance is good, the clear vision is ensured, and even high astigmatism, irregular astigmatism and no crystalline eye can be well corrected; (3) the indications for scleral lenses are rather broad: general myopia, hyperopia, astigmatism, and diopter spread; in particular, high myopia, high hyperopia, high astigmatism and irregular astigmatism; keratoconus or presbyopic patients, due to various refractive keratoses (e.g., RK, PRK, LASIK), keratoplasty, keratopathy (e.g., corneal trauma, keratitis), and resulting in irregular astigmatism of the cornea; all wearers who are unadapted and unable to discard contact lenses due to various complications resulting from wearing contact lenses.
Compared with soft glasses and frame glasses, the sclera contact lens can obviously improve the visual quality of human eyes, the key reason is that a tear layer of hundreds of microns is formed between the front surface of the cornea and the rear surface of the sclera lens, and the refractive index of the tear layer is similar to that of the cornea, so that the change of wavefront aberration caused by various defects and deformations of the front surface of the cornea can be obviously reduced, the visual quality of a patient is improved, but the visual quality is improved to a certain extent due to the fact that most of the optical areas of the sclera contact lens are of simple spherical design at present, but glare can occur to a certain extent to a great extent when a plurality of patients wear, especially when pupils become large at night, and the condition of the visual object is unclear, and the main reason is that the condition of the cornea is relatively poor in general case for patients wearing the sclera lens, irregular astigmatism or regular high astigmatism exists, and even high-order aberration such as coma, clover and the like exists, and further improvement of the visual quality of the patient is greatly limited. Therefore, there is an urgent need to develop a scleral contact lens based on a phase modulation technique to solve the above technical problems.
In view of this, the present invention has been made.
Disclosure of Invention
The invention aims to provide a sclera contact lens based on a phase modulation technology, which is characterized in that firstly, a three-dimensional sagittal height distribution model of the front surface of a human eye cornea is established, secondly, a human eye optical system model after wearing the sclera contact lens is established based on a classical LB human eye model, thirdly, the rear surface of the sclera lens adopts a spherical design, which is mainly matched with the curvature radius of the front surface of the human eye, finally, a phase modulation function is overlapped on an optical area of the front surface of the sclera lens aiming at the wave front aberration actually existing in the whole eye, and the specific optical aberration of each incident view field is modulated, so that the balance or correction of target aberration is realized.
In view of the above-mentioned problems with the prior art, the present invention provides a scleral contact lens based on a phase modulation technique, the inner surface of which (the surface in contact with the cornea) can be divided into three parts generally from the middle outwards: an intermediate optical zone D1, a transition zone D2 and a landing zone D3, as shown in fig. 2, characterized by an optical zone that spans the cornea and does not contact the cornea to correct vision; the transition zone connects the optical zone and the landing zone, is located at the limbus, and is divided into two regions: the limbal zone is positioned at the limbus and keeps a certain gap with the limbus, and the limbus zone is used for adjusting the rise of the scleral lens and the compensation of the rise; the landing zone is the bearing area of the whole lens, is consistent with the radian of the sclera, and is tangentially contacted with the sclera, so that the sclera contact lens can be well fixed on the sclera, and an included angle is formed between the landing zone and the cornea, thereby facilitating tear exchange.
The anterior surface optical zone of the scleral contact lens and the inner surface optical zone of the scleral lens together provide optical imaging characteristics, the anterior surface optical zone having a base profile similar to a standard facet profile (planar, spherical, quadric) plus an additional phase term defined by zernike standard coefficients. The additional phase term is offset as the light passes through the facet and increases the optical path length of the light. This type of facet is actually a phase modulation added to the standard facet, the additional phase of the facet being defined as:
The phase function describes that on the basis of a standard curved surface, the modulation phase is increased at any radial wavelength position, so that the phase modulation function is realized. The standard surface profile (base profile) of the anterior surface optical zone of the scleral contact lens employs a hyperboloid design with higher order terms expressed by the following formula:
Wherein,
The conic coefficients may differ in both the X and Y directions, except for the base radius, alpha i and beta i are the X-direction and Y-direction higher order aspheric coefficients, respectively, the hyperboloid allowing direct assignment of Rx, ry, kx and Ky.
The profile of the anterior surface optical zone of the scleral contact lens, i.e., the profile after phase modulation, is expressed as:
The first term is the base profile, which together with the scleral posterior surface provides the power of the scleral contact lens, the second term is the higher order aspheric coefficients in the x-direction and y-direction, and the last term is the phase modulation term superimposed on the base profile.
The scleral contact lens is characterized in that the surface profile of the cornea of the human eye is measured by a cornea topographer to obtain a sagittal height distribution map of the front surface of the cornea, an equivalent curvature radius and a conical coefficient are fitted, and a sagittal height difference value is unfolded by a Zernike sagittal height coefficient:
the surface type of the discrete sampling of the front surface of the cornea of the sclera contact lens can also be directly converted into a phase surface by the following conversion modes:
discretizing the sagittal distribution of the anterior surface of the cornea in a two-dimensional xy plane, wherein deltay is the sagittal height of the sagittal plane of the anterior surface of the cornea at deltax displacement intervals, and the sagittal distribution can be directly subjected to phase transformation.
After simulation wearing, the sclera contact lens establishes a human eye imaging optical system after wearing, adopts a ray tracing method to calculate the distribution condition of retinal defocus when an on-axis view field and an off-axis view field are incident, takes the weighted sum of RMS values of a plurality of view field diffuse spots at the retinal position as an evaluation function, and the smaller the value is, the better the imaging quality is represented, namely:
The scleral contact lens is characterized in that plasma treatment is adopted integrally, the surface hydrophilicity is improved, the scleral contact lens is more comfortable to wear, and the plasma power is 10-2000W.
The refractive index of the scleral contact lens ranges from 1.4 to 1.6, and the oxygen permeability coefficient is (80-200) 10-11 (cm 2/s)[mlO2/(ml multiplied by mmHg) ].
The total diameter of the scleral contact lens ranges from 12.5mm to 24mm, and the curvature radius of the rear surface ranges from 6.4mm to 9.2 mm.
The design method comprises the following steps:
(1) The corneal topography instrument is adopted to obtain the information such as the curvature, thickness, anterior chamber depth and the like of the front and back surfaces of the cornea of the human eye, and the most critical is that the aspheric coefficient Q of the cornea of the human eye can be obtained in a personalized way.
(2) The method comprises the steps of establishing a human eye cornea front surface sagittal distribution model according to corneal front surface sagittal distribution data obtained by a cornea topography instrument, obtaining a difference value of an actual surface sagittal minus a fitting sagittal by adopting a fitting algorithm, and carrying out Zernike polynomial expansion on a residual error to finally obtain a front surface sagittal expression.
(3) The anterior surface sagittal height of cornea is converted into phase distribution data, which is imported into a personalized human eye model, and a complete personalized human eye model comprising the actual anterior surface of cornea is established.
(4) Based on the personalized human eye model, a human eye optical system model after wearing the sclera contact lens is built, and on-axis and off-axis light rays are built, so that light ray tracing is performed, as shown in figure 3.
(5) The rear surface of the sclera lens is matched with the front surface of the cornea of the human eye, the radius which is slightly flatter than the average radius of curvature of the front surface of the cornea is adopted, and the spherical design is adopted to match the radius of curvature of the front surface of the cornea of the human eye.
(6) The wavefront aberration distribution characteristics and the amplitude under the condition of different pupils of the whole eye are obtained through personalized human eye ray tracing, and the aberration values of targeted phase modulation and compensation are given according to the actual requirements of patients;
(7) For the wave front aberration actually existing in the whole eye, the superimposed phase modulation function is arranged in the optical area of the front surface of the sclera lens, and the specific optical aberration of each incident view field is modulated, so that the balance or correction of the target aberration is realized.
(8) The final scleral anterior surface profile is determined.
(9) Lathe and polishing. The raw material for processing is high oxygen permeability material, the material reaches a glass state at normal temperature, and the front and rear surfaces are processed by adopting a diamond single-point turning technology. And removing lane lines and fine scratches through single-head polishing.
(10) The surface hydrophilicity is improved after plasma treatment, the wearing is more comfortable, and the plasma power is 10-2000W.
The sclera contact lens based on the phase modulation technology provided by the invention has the beneficial effects that the modulation/demodulation phase is superposed on the optical surface of the front surface of the sclera contact lens, and the wavefront aberration of the whole eye is modulated in a personalized way, so that the sclera contact lens has the following beneficial effects:
1. Meets the requirements of the design on the wavefront aberration of the human eye.
2. Accurately compensates for various wavefront aberrations of the anterior surface of the patient's cornea.
3. Greatly improves the vision level and vision quality of the patient.
Drawings
FIG. 1 is a schematic illustration of a scleral contact lens worn by a human eye;
FIG. 2 is a schematic view of a scleral contact lens;
FIG. 3 is a view of a human eye ray tracing of a scleral contact lens;
FIG. 4 is a flow chart of a design of a scleral contact lens based on a phase modulation technique;
FIG. 5 Zernike coefficient comparison before and after center field modulation under a 6mm pupil, sphere before modulation and aspherical after modulation;
FIG. 6 Zernike coefficient comparison before and after 5 degree field modulation at 6mm pupil, sphere before modulation and aspherical after modulation;
FIG. 7 Zernike coefficient comparison before and after 10 degree field modulation at 6mm pupil, sphere before modulation and aspherical after modulation;
FIG. 8 is a 6mm pupil, 0 degree field modulation front-to-back MTF comparison;
FIG. 9 is a 6mm pupil, 5 degree field modulation front-to-back MTF comparison;
fig. 10 is a 6mm pupil, -5 degree field modulation front-to-back MTF comparison.
Detailed Description
The invention will be further described with reference to specific examples and figures to aid in the understanding of the invention.
Example 1
As shown in fig. 2, which is a schematic structural view of a scleral contact lens, the inner surface (the surface in contact with the cornea) of the scleral contact lens can be divided into three sections generally from the middle to the outside: an intermediate optical zone D1, a transition zone D2, and a landing zone D3, the anterior surface optical zone of the scleral contact lens providing optical imaging characteristics in combination with the scleral lens interior surface optical zone.
The preparation steps of the scleral contact lens are as follows, and the design flow chart is as shown in fig. 4:
(1) The corneal topography instrument is adopted to obtain the information such as the curvature, thickness, anterior chamber depth and the like of the front and back surfaces of the cornea of the human eye, and the most critical is that the aspheric coefficient Q of the cornea of the human eye can be obtained in a personalized way.
(2) The method comprises the steps of establishing a human eye cornea front surface sagittal distribution model according to corneal front surface sagittal distribution data obtained by a cornea topography instrument, obtaining a difference value of an actual surface sagittal minus a fitting sagittal by adopting a fitting algorithm, and carrying out Zernike polynomial expansion on a residual error to finally obtain a front surface sagittal expression.
(3) The anterior surface sagittal height of cornea is converted into phase distribution data, which is imported into a personalized human eye model, and a complete personalized human eye model comprising the actual anterior surface of cornea is established.
(4) Based on the personalized human eye model, a human eye optical system model after wearing the sclera contact lens is built, and on-axis and off-axis light rays are built, so that light ray tracing is performed, as shown in figure 3.
(5) The rear surface of the sclera lens is matched with the front surface of the cornea of the human eye, the radius which is flatter than the average radius of curvature of the front surface of the cornea is adopted, and the spherical design is adopted to match the radius of curvature of the front surface of the cornea of the human eye.
(6) The wavefront aberration distribution characteristics and the amplitude under the condition of different pupils of the whole eye are obtained through personalized human eye ray tracing, and the aberration values of targeted phase modulation and compensation are given according to the actual requirements of patients;
(7) For the wave front aberration actually existing in the whole eye, the superimposed phase modulation function is arranged in the optical area of the front surface of the sclera lens, and the specific optical aberration of each incident view field is modulated, so that the balance or correction of the target aberration is realized.
(8) And determining the front surface profile of the final scleral mirror, and performing lathe and polishing processing. The raw material for processing is high oxygen permeability material, the material reaches a glass state at normal temperature, and the front and rear surfaces are processed by adopting a diamond single-point turning technology. And removing lane lines and fine scratches through single-head polishing.
(9) The surface hydrophilicity is improved after plasma treatment, the wearing is more comfortable, and the plasma power is 10-2000W.
Analysis and discussion of results:
The distribution of on-axis and off-axis light on the retina of a human eye is obtained by combining the established personalized human eye model by adopting light ray pursuit software, as shown in figure 3. As can be seen, diopter errors of on-axis points have been corrected, light is focused on the retina, then off-axis light is focused in front of or behind the retina, the targeted modulated zernike terms are astigmatism terms Z5 and Z6, coma terms Z7 and Z8 and spherical aberration term Z11, respectively, for a patient with sclera, there will be astigmatism terms and coma terms due to corneal irregularities and distortions, for off-axis light, coma is a very pronounced aberration for a patient with keratoconus, this example is intended to represent a targeted aberration modulation capability.
Fig. 5, at a 6mm pupil, a comparison of the zernike coefficients before and after the central field of view modulation, with the sphere before modulation and the aspherical surface after modulation.
Fig. 6 zernike coefficient comparisons before and after 5 degree field modulation at a 6mm pupil, sphere before modulation and aspherical after modulation.
Fig. 7, under a 6mm pupil, a comparison of the zernike coefficients before and after modulation of the 10 degree field of view, with the sphere before modulation and the aspherical surface after modulation.
The method comprises the steps of obtaining basic parameters of an individualized human eye by adopting a cornea topography instrument test, establishing a human eye model, obtaining aberration distribution conditions under different fields of view after ray tracing by using a fitted spherical average curvature radius of the front surface of the cornea, uniformly adopting 6mm pupils for comparison convenience, wherein the aberration difference of the human eye is obvious, and the aspheric surface refers to the average curvature radius of the front surface of the cornea of the human eye obtained by adopting a cornea topography, and carrying out Zernike polynomial expansion on the rest sagittal height after fitting to obtain a final plane distribution model, and carrying out ray tracing and modulation compensation. The aberration distribution of different fields before and after modulation is shown in figures 5-7, and it can be obviously seen that the aberration is obviously reduced before and after modulation, so as to achieve the purpose of phase modulation.
Fig. 8-10 are graphs comparing MTF before and after modulation of a 0 degree field of view, a 5 degree field of view, and a-5 degree field of view under a 6mm pupil, respectively, and it can be seen that the Modulation Transfer Function (MTF) of the corresponding field of view is also significantly improved due to a significant reduction in aberration.
The phase modulation function can be directly overlapped on the optical area of the front surface of the sclera, so that the later lathe processing and forming are facilitated, and the phase modulation technology can be used for carrying out modulation compensation on the actually detected human eye aberration in a targeted manner, and has wider adaptability and universality.
Specific examples are set forth herein to illustrate the invention in detail, and the description of the above examples is only for the purpose of aiding in understanding the core concept of the invention. It should be noted that any obvious modifications, equivalents, or other improvements to those skilled in the art without departing from the inventive concept are intended to be included in the scope of the present invention.
Claims (4)
1. A scleral contact lens based on a phase modulation technique, characterized in that the inner surface of the scleral contact lens, i.e. the surface in contact with the cornea, is divided from the middle outwards into three parts in total: an intermediate optical zone, a transition zone, and a landing zone, the optical zone traversing across and not in contact with the cornea to correct vision; the transition zone connects the optical zone and the landing zone, is located at the limbus, and is divided into two areas: the limbal zone is positioned at the limbus and keeps a gap with the limbus, and the limbus zone is used for adjusting the rise of the scleral lens and the compensation of the rise; the landing area is the bearing area of the whole lens, is in tangential contact with the sclera in accordance with the radian of the sclera, so that the sclera contact lens can be well fixed on the sclera, and an included angle is formed between the landing area and the cornea, thereby facilitating tear exchange; converting the front surface sagittal height of the cornea into phase distribution data, leading the phase distribution data into a personalized human eye model, establishing a complete personalized human eye model comprising the actual front surface of the cornea, establishing a human eye optical system model after wearing a sclera contact lens through personalized human eye ray tracing, establishing vertical axis and different axis external rays, carrying out ray tracing to obtain wavefront aberration distribution characteristics and amplitude under the condition of different pupils of the whole eye, providing aberration values of targeted phase modulation and compensation according to actual requirements of patients, establishing a human eye optical system model after wearing the sclera contact lens based on the personalized human eye model, establishing vertical axis and different axis external rays, carrying out ray tracing, matching the rear surface of the sclera lens with the front surface of the human eye cornea, finally realizing balance or correction of target aberration, and determining the front surface profile of the final sclera lens;
The anterior surface optic zone of the scleral contact lens cooperates with the inner surface optic zone of the scleral lens to provide optical imaging characteristics, the anterior surface optic zone having a base profile similar to a standard facet profile plus an additional phase term defined by a zernike standard coefficient that deflects light rays as they pass through the facet and increases the optical path length of the light rays, the facet being in effect an increased phase modulation based on the standard facet profile, the additional phase of the facet being defined as:
Here, N is the number of zernike coefficients in the series, a i is a coefficient in a zernike polynomial, ρ is a normalized radial ray coordinate value, ψ is an angle coordinate value of the ray, D is a diffraction order, the phase function describes that on the basis of a standard curved surface, by adding a modulation phase at an arbitrary radial wavelength position, a i is a phase shift in wavelength unit, λ corresponds to 2pi, Is wave surface distribution in a polar coordinate system;
the standard surface of the anterior surface optical zone of a scleral contact lens is designed with a hyperboloid with higher order terms expressed by the following equation:
Wherein,
The conic coefficients may differ in both the X and Y directions except for the base radius, alpha i and beta i being the X and Y directions higher order aspheric coefficients, respectively, the hyperboloid allowing direct specification of Rx, ry, kx and Ky;
The profile of the anterior optical zone of the scleral contact lens, i.e., the profile after phase modulation, is:
The first term is a base profile that, together with the scleral posterior surface, provides the power of the scleral contact lens, followed by the higher order aspheric coefficients in the x-direction and y-direction, and the last term is a phase modulation term superimposed on top of the base profile;
The surface profile of the cornea of the human eye is measured by a cornea topographer to obtain a sagittal height distribution map of the front surface of the cornea, the equivalent radius of curvature and conic coefficient are fitted, and the sagittal height difference value is unfolded by using a Zernike sagittal height coefficient:
Wherein k is a conic coefficient of a surface of the cornea front surface, c is an inverse of a radius of curvature, N is a zernike number, B i is a zernike coefficient value, ρ is a normalized radial ray coordinate value, and ψ is an angle coordinate value of a ray;
The discrete sampled surface shape of the anterior surface of the cornea is directly converted into a phase surface in the following manner:
discretizing the sagittal distribution of the anterior surface of the cornea in a two-dimensional xy plane, wherein deltay is the sagittal height of the sagittal plane of the anterior surface of the cornea at deltax displacement intervals, and the sagittal distribution can be directly subjected to phase transformation;
after the sclera contact lens is worn in a simulation mode, a human eye imaging optical system after the lens is worn is established, an on-axis view field and an off-axis view field are calculated by adopting a ray tracing method, the distribution condition of retinal defocus is calculated, the weighted sum of RMS values of a plurality of view field diffuse spots at the retinal position is used as an evaluation function, the smaller the value is, the better the imaging quality is represented, namely:
wherein: s i is the weighting coefficient, RMS i is the speckle RMS value of the i fields of view, and T is the total number of fields of view involved in the calculation.
2. The scleral contact lens based on the phase modulation technique according to claim 1, wherein the whole body is treated by plasma, so that the surface hydrophilicity is improved, the lens is more comfortable to wear, and the plasma power is 10-2000W.
3. The scleral contact lens according to claim 1, wherein the refractive index is in the range of 1.4-1.6 and the oxygen permeability coefficient is in the range of 80*10-11(cm2/s)[mlO2/(ml×mmHg)]-200*10-11(cm2/s)[mlO2/(ml×mmHg)].
4. A scleral contact lens based on the phase modulation technique according to claim 1, characterized in that its total diameter ranges between 12.5mm and 24mm and the radius of curvature of the rear surface ranges between 6.4mm and 9.2 mm.
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| CN202210500567.XA CN114779497B (en) | 2022-05-09 | 2022-05-09 | Scleral contact lens based on phase modulation technology |
| PCT/CN2022/131983 WO2023216540A1 (en) | 2022-05-09 | 2022-11-15 | Scleral contact lens based on phase modulation technology |
| GBGB2412906.6A GB202412906D0 (en) | 2022-05-09 | 2022-11-15 | Scleral contact lens based on phase modulation technology |
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2022
- 2022-05-09 CN CN202210500567.XA patent/CN114779497B/en active Active
- 2022-11-15 GB GBGB2412906.6A patent/GB202412906D0/en active Pending
- 2022-11-15 WO PCT/CN2022/131983 patent/WO2023216540A1/en unknown
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| CN114779497A (en) | 2022-07-22 |
| GB202412906D0 (en) | 2024-10-16 |
| WO2023216540A1 (en) | 2023-11-16 |
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