JP2020525842A - Ophthalmic lens design based on topology - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-invasive method for designing and manufacturing a custom-fit scleral lens suitable for the surface of a patient's eye. The method includes (a) a step of operating an eye shape analysis device to provide a three-dimensional model of an eye. The 3D model is designated as an array of pixel data points, which array contains the 3D positions of each pixel data point. Each pixel data point represents an x, y, z position on the surface of the eye and a corresponding intensity value of each pixel data point. The spatial relationship between the pixel data points accurately reflects clinically visible eye abnormalities, after correcting for artifacts caused by impulsive eye movements and random eye movements. The sampling density of the pixel data points is dense enough to characterize the clinically visible anomaly as well as one within the pupil, iris and blood vessel. The method further comprises (b) determining from the data points an array of a plurality of independent data points that define the rear surface of the lens. The density of this data point is high enough to allow the posterior surface of the lens to be adjusted in response to abnormalities in the eye. [Selection diagram] Fig. 1

Description

Related application

(Cross-reference of related applications)
This application claims priority to co-pending US patent application Ser. No. 15/634,631 filed June 27, 2017, “TOPOPLOGY GUIDED OCULAR LENS DESIGN”. To do. The entire contents of that application are incorporated herein by reference.

(background)
Scleral lenses have been used to restore visual acuity and alleviate discomfort due to dry eye disorders in patients with injured or diseased corneas. The incidence of dry eye in the population is estimated to be 15%, of which about 2 out of 10 are severe enough to significantly affect quality of life. Globally, this represents 3% of the world's population, and the United States alone represents approximately 9.24 million dry eye patients.
In addition, millions of people, who usually do not have dry eyes, feel dry after wearing standard contact lenses for a long time.

As shown in FIG. 1, a scleral lens is a large contact lens that is placed in the white scleral region of the eye and vaulted over the cornea. The gap 103 between the posterior medial surface of the lens and the cornea is typically filled with saline which acts like a liquid bandage to soothe the thousands of nerves on the corneal surface. .. Depending on the application, agents to help heal the injured eye can be added to or used in place of the saline.

In order to ensure that the lens does not stimulate nerves on the scleral surface, the shape of the bearing surface 100 shown in FIG. 1 includes the sclera of the patient (including the area normally covered by the eyelids). ) Must match the unique 3D shape.
Unfortunately, there is currently no method to accurately measure scleral morphology. As a result, in order to find a lens that fits comfortably, one has to select a lens suitable for the scleral surface of the patient from a set of up to 2000 kinds of trial lenses. This is an iterative, costly and time consuming process that can take weeks. Even if a trial lens that fits well can be found, there is often a need to make further modifications to the trial lens to optimize its fit.

As shown in FIGS. 2a, 2b, 2c, and 2d, if the patient's eye has an abnormal shape due to, for example, an injury or a lesion, a trial for following the irregular shaped bearing surface shape. There is no lens and it may be impossible to fit.
There is also a field of smaller diameter scleral lenses in which the resting surface rests on both sides of the limbus that spans the sclera and the outermost region of the cornea. In the case of an injured eye, such a lens may need to be fitted, as it may have to follow both the corneal and scleral injuries of the bearing surface as shown in Figures 2c and 2d. It can be even more difficult.

With prior art approaches, even if a good-fitting trial lens could be found, the optical part that needs to be vaulted in front of the patient's cornea to properly image the light on the retina. Is further provided with a step of determining its optical characteristics.

It is important to emphasize that while the trial lens itself does not have an optical component for vision correction, the design of such an optical component can be done by placing the trial lens in the patient's eye and wearing it. The point is that it must be kept. This is because a fluid (typically saline) is placed between the posterior surface of the scleral lens and the anterior surface of the cornea, so that the light rays at both the fluid-corneal and fluid-scleral lens posterior boundaries. This is because the way of refraction (how light rays are bent) changes.

With the trial lens worn, a doctor or an ophthalmologist will perform a photorefractive examination (ie, placing various known lenses in front of the trial scleral lens). This determines the optical power of the optical portion of the scleral lens.
Upon completion of the refraction test, the required optical power and the best-fitting bearing surface shape of the trial lens are known, and it becomes possible to manufacture a custom scleral lens for each patient.

Gemoules' title "Method of Fitting Rigid Gas-permeable Contact Lenses from High Resolution Imaging" describes the replacement of trial lenses. Prior art attempts to measure scleral morphology without repeated iterations have been described. The Gemoules fitting method is based on using a digital acquisition device to acquire a two-dimensional cross-sectional sagittal image of the eye, including the sclera, as shown in Figure 3a. However, since the shape of the eye is not two-dimensional and is three-dimensional as shown in FIGS. 5a, 5b, and 5c, the cross-sectional image is not suitable as an approximation of the three-dimensional image. This limit is illustrated by Figure 3b, which shows an injured eye. In FIG. 3b, a plurality of independent meridians, which are present on the surface of the injured area, are drawn to make the posterior surface of the lens follow the surface topology of the eye well. The spatial Z heights of the radial meridians can take different values independently of each other. Although the cross-sectional sagittal image shown in FIG. 3a can easily correspond to the scan image (scan) taken at line 301-307 in FIG. 3b, in this cross-sectional sagittal image, the scan lines 302, 303, 304, 305 The scan lines of (may be said to be meridian) do not reveal the presence of injuries. Moreover, although not mentioned in Gemoules, the attempt to obtain multiple three-dimensional shape approximations by acquiring multiple independent two-dimensional scan images around the eye causes the spatial position of the eye to move between scans. I've failed so far.

Svochak's “Contact Lens with Controlled Shape” (Patent Document 2) is a contact lens that sits on the cornea and has four base curves, one in each quadrant. Has proposed a method for producing a contact lens whose posterior surface shape is defined. This approach to designing the bearing surface of the scleral lens has a number of limitations. First, the scleral lens is unable to follow small injuries or protrusions or irregular shapes in regions of substantially different shapes, as shown in Figures 2a, 2b, 2c, 2d of the present application. Second, the corneal base curve is almost always different from the sclera base curve with the limbus as the demarcation point. Whereas a scleral lens that spans both regions must follow such a complex change in curvature (as indicated by arrow 1003 in FIG. 10) at the interregional boundary, Svochak follows the cornea. I only deal with lenses. Third, it is not possible with such a solution with four base curves to follow every possible change in the three-dimensional topology of the eye.
As in the case of the injured eye of FIGS. 2a-2d, Svochak's method cannot be applied if four base curves are not sufficient to define the shape of the eye and the shape of the optimized lens that fits well. ..

The title "Prosthetic Lenses and Methods of Making the Same" by Sindt in Patent Document 3 obtains a physical impression of the eye by applying a foreign body to the surface of the eye. The method (to make a mold) is described. Then, by using this impression, the rear surface of the lens is determined. This procedure is extremely invasive and is not well tolerated by patients with sensitive eyes.

U.S. Pat. No. 7,862,176 US Pat. No. 7,296,890 US Patent No. 9551885

(Outline of preferred embodiment)
As a result, a non-invasive method for designing and manufacturing a custom-fit scleral lens having a shape that matches the surface of the patient's eye is desired.

In view of the limitations of the prior art, as a first method, it is possible to design a scleral lens bearing surface that follows the actual three-dimensional shape of the sclera without using a trial lens. The method will be described. The lens bearing surface or posterior surface resting on the eye is described by a three-dimensional array of data points each representing independent x, y, z measurement positions on the surface of the eye. This new capability can be applied to any scleral lens design, whether it alleviates dry eye symptoms or restores visual acuity in patients with injured or diseased corneas. It is possible. In the approach described in this specification, unlike Gemoules that creates the posterior surface of the lens using one sagittal image and Svochak that creates the posterior surface of the lens using four base curves, each data on the lens bearing surface is The points may correspond to unique three-dimensional x,y,z measurements on the patient's eye. Unlike the prior art, the lens design is not limited to only four base curves, one in each quadrant. Rather, the upper limit on the number of radial meridians used to design the lens is limited only by the spatial resolution of the shape analyzer. Each meridian may be different (typically different from each other) as shown in FIG. 3b. FIG. 3d is an actual three-dimensional high-resolution, high-density scan image of the patient's eye, showing a three-dimensional array of independent measurement data points on the surface of the eye, and It is depicted that the three-dimensional array can fit the details on the surface. FIG. 3d was obtained using the Bishop type shape analyzer shown in FIG. FIG. 3c shows that this data can be used to produce contact lenses with a posterior surface shaped to match the unique topology of the patient's eye.

As a second method, a method that enables the design of the optical portion of the scleral lens without the need to perform a refraction test with the scleral lens attached to the eye will be described. This is because if you want to wear a scleral lens for the purpose of relieving dry eye symptoms or for some other reason, use glasses and contacts even if you already have sufficient eyesight. It can also be applied to patients who have good visual acuity.

As a third method, a method that enables the design of the entire scleral lens including the bearing surface and the optical portion without the need for a trial lens will be described. In this embodiment, the scleral lens bearing surface that is specific to each patient follows the actual three-dimensional shape of the patient's eye, but does not require the use of trial lenses to determine this shape. .. This is because if you want to wear a scleral lens for the purpose of relieving dry eye symptoms or for some other reason, use glasses and contacts even if you already have sufficient eyesight. It can also be applied to patients who have good visual acuity.

The fourth method is a method that enables 3D printing (stereoscopic printing) of a lens designed using the method described above.

It is sectional drawing of the scleral lens with which the eye was equipped. FIG. 2a shows an eye injury. FIG. 2b is another view showing an eye injury. FIG. 2c is yet another view showing eye injury. Figure 2d is yet another view showing eye injury. FIG. 3a is a cross-sectional sagittal image of the eye. FIG. 3b is an image of an injured eye with multiple independent meridians in one quadrant. FIG. 3c is a cross-sectional view of the lens, showing that its front and back surfaces can be designed independently of each other. FIG. 3d is a scanned image with motion compensation of the human eye, acquired with a Bishop scanning device. It is a photograph of a Bishop type shape analyzer. FIG. 5a is a three-dimensional model of the human eye, an image depicting a front view. FIG. 5b is a three-dimensional model of the human eye, an image depicting a side view. FIG. 5c is a three-dimensional topology map of the human eye, an image depicting a front view. It is a figure which shows a mode that a topology map and the three-dimensional model of the said whole eye are produced|generated by splicing together the image of several gaze directions about an eye. FIG. 7a is the topology map of FIG. FIG. 7b is the topology map of FIG. FIG. 8a is a diagram in which the data of the central cornea and the sclera are superimposed on the scanned image of the eye. FIG. 8b is a diagram in which the data of the central cornea and the sclera are superimposed on the eye topology map. FIG. 9a shows a three-dimensional model with the selected bearing surface of the eye superimposed. FIG. 9b is a diagram in which the designated bearing surface of the eye is superimposed on the topology map. FIG. 10a is a diagram in which the central surface of the cornea of the eye is superimposed on the three-dimensional model. FIG. 10b is a diagram in which the central surface of the cornea of the eye is superimposed on the topology map. FIG. 10c is a side view of the eye model, which also depicts a lens bearing surface having a shape that matches the eye topology. FIG. 6 shows a scleral lens having a vaulted optical portion, a transition area and a bearing surface. FIG. 12a is a diagram showing an eye wearing corrective glasses. FIG. 12b is a diagram showing a case where a scleral lens is attached to the eye. FIG. 13a is a diagram showing how a light ray travels through the glasses into the eye. FIG. 13b is a diagram showing how the light rays travel through the scleral lens and into the eye. FIG. 14a is a diagram showing the relationship between the light rays of the spectacles and the light rays of the scleral lens. FIG. 14b is another diagram showing the relationship between the light rays of the spectacles and the light rays of the scleral lens. It is a figure which shows the visual field of the eye in a fixed gaze direction. It is a figure which described Snell's law. It is the figure which illustrated Snell's law in the boundary of an air-cornea. It is the figure which illustrated Snell's law in the boundary of a physiological saline-cornea. FIG. 19a shows a first computer model needed to design the scleral lens optics. FIG. 19b shows a second computer model needed to design the scleral lens optics. FIG. 19b is an enlarged cross-sectional view of FIG. 19b, with light rays near the eye depicted. 19a and 19b are enlarged views in which FIG. 19a and FIG. 19b are overlapped with each other, and the relationship between the light ray near the eye in FIG. 19a and the light ray near the eye in FIG. 19b is depicted. 22a is a three-dimensional representation of FIG. 19a. FIG. 22b is a three-dimensional representation of FIG. 19b. FIG. 22c is a diagram in which FIG. 22a and FIG. 22b are overlapped, and the relationship between the light ray in FIG. 22a and the light ray in FIG. 22b is depicted. FIG. 23a is a diagram showing how a light ray travels through the air into the eye. FIG. 23b is a diagram showing how the light rays travel through the scleral lens and into the eye. FIG. 24a is a diagram showing a relationship between a light ray when a scleral lens is attached to an eye and a light ray when a scleral lens is not attached to an eye. FIG. 24b is another diagram showing the relationship between the light rays when the scleral lens is attached to the eye and the light rays when the scleral lens is not attached to the eye. FIG. 25a shows a first computer model needed to design the scleral lens optics. FIG. 25b shows a second computer model needed to design the scleral lens optics. FIG. 26 is an enlarged view obtained by superimposing FIG. 25 a and FIG. 25 b, and illustrates the relationship between the light ray near the eye in FIG. 25 a and the light ray near the eye in FIG. 25 b. FIG. 27a is a three-dimensional representation of FIG. 25a. FIG. 27b is a three-dimensional representation of FIG. 25b. FIG. 27c is a superposed view of FIGS. 27a and 27b and illustrates the relationship between the rays of FIG. 27a and the rays of FIG. 27b. FIG. 3 is a block diagram illustrating a preferred embodiment of a system that may be used to implement the methods described herein.

(Detailed Description of Preferred Embodiments)
Conventionally, the three-dimensional shape of the bearing surface of a scleral lens has been obtained by using a trial lens as described above. However, the latest advances in ocular topological scanning devices have provided a way to directly measure the three-dimensional shape of the sclera. For example, as disclosed in US Pat. No. 9,398,845 and US Pat. No. 9,489,753 (both of which are incorporated herein by reference), a shape analyzer (Topographer) as developed by Bishop et al. It is possible to three-dimensionally scan all areas of the sclera, including the area covered by the eyelids. FIG. 4 shows a Bishop type shape analyzer. Technical details regarding the operation of the Bishop-type shape analyzer are contained in the above cited document. The Bishop shape analyzer also corrects eye movements during any scanning process. FIG. 5 shows a three-dimensional topological scan image of the human eye obtained by using the Bishop type shape analyzer. During eye scanning, the eyelids were kept open using a speculum to expose the upper and lower areas of the sclera. Figure 5a is the resulting front view, Figure 5b is the resulting side view, and Figure 5c is the resulting contour map [intensity is proportional to height]. ]. Figures 5a, 5b and 5c were all generated from a single 3 second scan of the eye.

Even if it is not desirable to use an eyelid opener for some reason, the Bishop shape analyzer exposes various areas of the sclera in different eye gaze directions as shown in the scanned image of the eye as shown in FIG. It is possible to obtain a plurality of these while splicing them together. Then, the shape analysis device can synthesize a single three-dimensional model capable of extracting the bearing surface by combining the scan images. The scanner corrects for any eye movement during and between scans. 7a is a height contour map, and FIG. 7b is a three-dimensional model generated by stitching together a plurality of gaze direction scan images shown in FIG.

In the following description, the three-dimensional model of the eye and the topology map as shown in FIGS. 5 to 12 obtained by using the Bishop type shape analyzer (US Pat. No. 9,398,845) and the eyelid opener are used. However, to implement and implement the methods and systems described herein, those that use optical triangulation, those that use light interference, those that use OCT technology, and patterns. Enables 3D scanning of the scleral lens bearing area without using pattern projection, interferometry, or eye movement artifacts. Any shape analyzer can be used, such as with any other eye scanning technique that

The following steps are performed to determine the bearing surface of the scleral lens:
1. An eye shape analyzer, such as a Bishop shape analyzer, is used to measure the three-dimensional topology of the area of the patient's eye used to design the posterior surface of the lens. 8a and 8b are examples of bearing areas in the sclera, indicated by arrow 801 in FIG. 8a and arrow 802 in FIG. 8b. The resulting topology information, obtained as a set of data points, must be free of motion blur to represent the actual shape of the eye. As shown in Figures 8a and 8b, each data point represents an independent x,y,z measurement position on the surface of the eye.
2. Define the position, width and size of the lens bearing surface in the eye. As an example, FIGS. 9a and 9b show the bearing surface located in the sclera. This bearing surface is indicated by arrow 901 in Figure 9a, arrow 902 in Figure 9b and arrow 1001 in Figure 10. However, the bearing surface may straddle the cornea and the sclera, or it may contact any part of the eye. From the information of the bearing surface, the rear surface of the lens has a high density of sample points to follow the actual three-dimensional topology of the eye and over 360° in the bearing area as shown in FIGS. 9a and 9b. Generate as it exists. This design approach results in a posterior surface having a shape that resembles the molded impression of the eye. The posterior surface can include injured areas and/or irregular areas on the bearing surface.
3. When the lens is a vault over the central region of the cornea, the pupil from the bearing surface of the scleral lens to the central surface of the cornea is determined from the three-dimensional model or three-dimensional topology map obtained from the shape analysis device. Extract the maximum height above (eg, height H1 indicated by arrow 1002 in FIG. 10c).
4. The posterior surface of the scleral lens optical portion, indicated by arrow 1101 in FIG. 11, is designed to cover the cornea while forming a clearance distance 1107. This ensures that the posterior surface of the scleral lens does not contact the cornea. For scleral lenses overlaid on the cornea, clearance distances are typically in the range of 100-300 microns.
5. Identify scars or injuries in the scleral and/or corneal regions, as shown in FIGS. 2a-2d, which may prevent the lens from properly and/or comfortably seating on the eye. If necessary, the back surface of the lens is elevated to cover the injured portion indicated by the arrow 1102 in FIG. What is important is that the shape analyzer surely has sufficient spatial resolution to detect such an abnormal portion. Such scars and injuries may be caused by a worker checking a video camera image as shown in FIGS. 2a to 2d or 3b (the video camera image is also provided by the shape analysis device) and/or It can be identified by examining the three-dimensional topology data.
6. In the case of a scleral lens covered with fluid between the cornea and the center of the posterior surface of the lens, the lower valley or trough pointed by arrow 1103 in the eye topology that naturally occurs below the lens bearing surface. Tears into the area covered by the lens by utilizing the group and/or by forming at least one or more small raised gaps below the posterior surface of the lens as indicated by arrows 1104, 1105. Free to flow in and out. Such a gap also prevents the formation of an excessive suction between the lens and the eye, which can make removal of the lens difficult. Such valleys may be identified by manipulating and inspecting the 3D topology map and/or model and/or the video image.

Although the posterior surface of the lens is seated on the sclera in FIGS. 8-11, the same technique for designing the posterior surface of the lens applies to any lens placed on any part of the eye. It is possible to In addition, in that case also:
• The entire lens bearing area of the eye is described by a three-dimensional array of independent measurement data points provided by the eye shape analyzer.
● The spatial relationship between the data points is corrected for eye movement during scanning and/or does not include artifacts due to motion blur.
● Extract the eye topology in the bearing area to generate the posterior surface of the lens.
● Each data point on the back surface of the lens represents an independent x, y, z measurement position on the surface of the eye.
Hereinafter, a method of designing the scleral lens optical portion based on the lens rear surface designed as described above without mounting a series of trial lenses on the eye will be described.

(Design of scleral lens optics specialized for each patient without using trial lens)
While the patient wants to wear a scleral lens to mitigate dry eye or dry eye symptoms due to contact lenses, a clear image on the retina can be obtained even if the patient does not need glasses or corrective lenses. A scleral lens that has sufficient visual acuity to produce must be designed so that when applied to the eye, the visual acuity is maintained at the same level as it was prior to the application of the scleral lens. I have to.

Alternatively, if the patient wears spectacles to produce a clear image on the retina or needs to wear a corrective lens on the anterior part of the eye, this visual acuity should be added to the optical part of the scleral lens. It is also possible to incorporate a correction function. When the scleral lens in this case is attached to the eye, the same image as that formed when the correction lens is attached to the front part of the eye is reproduced on the retina as shown in FIGS. 12a and 12b. Must be designed to. That is, the total photorefractive characteristics between the object (the candle in FIGS. 12a and 12b) and the retina must be the same between the optical configuration shown in FIG. 12a and the optical configuration shown in FIG. 12b. I have to. These two types of optical configurations are described in detail in FIGS. 13a and 13b (repeatedly, the image projected on the retina is the same in both configurations). The only difference between FIG. 13a and FIG. 13b is the condition outside the eye in front of the cornea. In both configurations, the inside of the patient's eye has not changed at all, and in both configurations, a clear image must be projected on the retina, so that in FIG. 13a without the scleral lens. It can be concluded that the light rays inside the cornea and the light rays inside the cornea in FIG. 13b with the scleral lens are always the same in producing an in-focus image on the retina. .. Therefore, as shown in FIGS. 14a and 14b, all that is necessary is to match the rays that enter the inside of the cornea.

In addition, a fixed gaze viewing angle of the eye [typically “Optimizing Image Quality in the Radiologist's Field of Vision” by Xthona, A.,] , Barco Healthcare, 03 November 2015] and as shown in FIG. 15, just match the rays within ±10° for letters and ±30° for figures. It is enough to think that it is good.

Matching of light rays is accomplished using Snell's law, as shown in FIG. 16, which determines the degree of refraction as light travels between dissimilar materials. Snell's law is the following formula:
I _i sinα _i =I _r sinα _r
Given by.
(Where I _i is the refractive index of the incident beam side material, α _i is the incident angle of the incident beam with respect to a straight line drawn orthogonal to the incident surface, and I _r is the refractive index of the refractive beam side material. Yes, α _r is the angle of incidence of the refracted beam on a straight line drawn orthogonal to the exit surface.)

When a light ray enters the eye at a right angle to the corneal surface, the incident angle (α _i ) is zero and sin0=0, so the light ray passes straight through the corneal surface without refraction (without bending). To do. However, when an off-axis light ray is incident on the corneal surface, the ray is bent toward the axis perpendicular to the corneal surface (perpendicular axis). As an example, when a scleral lens is applied to the eye, a ray of light incident from the air (I _i =1.00) into the cornea (I _r =1.376) at a 30° angle of incidence is shown in FIG. As shown in, the angle is bent by 8.7° and the angle inside the cornea becomes 21.3°.

On the other hand, the 30° incident beam when the scleral lens was applied so as to contain saline between the posterior surface of the scleral lens and the cornea, resulted in a saline-corneal boundary as shown in FIG. At only 0.98° in total. This is because the difference between the refractive index of saline (I _i =1.335) and the refractive index of the cornea (I _i =1.376) is only 0.041. Therefore, most of the light refraction by the scleral lens needs to be performed at the air-sclera lens boundary in order to keep the same location where the incident light rays are distributed inside the cornea.

(Design of scleral lens with optics for vision correction)
Prior to designing a scleral lens, it is first necessary to determine where in the cornea the light rays will be placed by the corrective lens (glass or refractive lens) in order to provide good vision. This is accomplished by tracing light rays from a light source (candle 1401a in FIG. 14a) through the corrective lens 1402 and the anterior surface of the cornea 1403a to a three-dimensional reference plane 1404a located in the eye.

The exact location of the reference surface 1404a is not critical as long as it is planar in its entirety in the eye or other known 3D shape in its entirety in the eye. However, if the reference surface 1404a is placed inside the cornea near the front of the eye, it is not necessary to trace the light ray beyond this location, which facilitates calculation. FIG. 14a shows that the entire reference surface 1404a is placed inside the cornea.

The set of rays from the light source to the reference surface formed by the corrective lens is referred to as the "Reference Ray Set" and includes the following ray subsets as shown in Figure 14a. I'm out.
1. Light ray 1410a from the light source to the correction lens
2. Light ray 1411a from the correction lens to the cornea
3. Ray 1412a from cornea to reference surface

The degree of light refraction by the corrective lens is determined using Snell's law and the known shape of the corrective lens 1402. The degree of light refraction on the air-corneal surface is determined using Snell's law and the shape of the cornea 1403a provided by the three-dimensional shape analyzer.

The goal is to place the rays from the light source in the same approximate position in the cornea as in the corrective lens, within the constraints imposed by Snell's law and the technique used to fabricate the three-dimensional shape of the scleral lens surface. It is to design such a scleral lens.

To achieve this goal, the following steps are performed (see Figure 14b):
1. Each ray of the reference ray set is retraced from the reference surface 1404b inside the cornea to the outside of the eye (retrace), and stopped at the boundary 1403b of the cornea-saline fluid. Reference plane 1404b in FIG. 14b is a reference plane common to reference numeral 1404a in FIG. 14a, and is drawn again for convenience. The cornea 1403b is a cornea common to the reference numeral 1403a, and is drawn again for convenience.
2. Next, Snell's law is applied to the boundary of the cornea (1403b)-saline (1405) to calculate how much each ray bends at this boundary. The degree of light refraction at the cornea-saline boundary is calculated by using Snell's law, the refractive index of the cornea (T=1.376), and the shape of the cornea 1404b provided by the three-dimensional shape analyzer. To be done. This causes each ray to continue to travel from the saline solution (1405) to the posterior surface of the scleral lens 1406 at a new projected angle.
3. Snell's Law is then applied to the posterior surface-saline (1405) boundary of the scleral lens (1406) and the anterior surface-air boundary of the scleral lens (1406). The ray emerging from the front surface of the scleral lens (1406) is, within the constraints of Snell's law, the corresponding ray existing between the light source 1401a and the corrective lens 1402 of the set of reference rays indicated by the arrow 1410a in FIG. 14a. The shape of the three-dimensional front and back scleral lens surfaces is set so as to retraces, as close as possible. Adjust. Snell's law is applied using the index of refraction of saline (I=1.335). The goal when this design is complete is to match the intraocular rays 1412a, 1412b with each other and the extraocular rays 1410a, 1410b with each other as shown in FIGS. 14a and 14b.

Performing this conceptual optical design procedure for the scleral lens makes it possible to create the actual scleral lens optics that can be used in place of the spectacles worn to correct myopia. Design performance can be assessed by superimposing a reference ray set of configurations for spectacles on the corresponding rays of the configuration for scleral lenses. The front surface of the scleral lens refracts light more than the back surface for the same angle of incident light. This is because the difference between the refractive index of the scleral lens material (1.424) and the refractive index of saline solution (1.335) on the rear surface is 0.089, whereas the refractive index of air on the front surface. This is because the difference between (1.00) and the refractive index of the scleral lens material (1.424) is 0.424, which is more than 4.7 times the difference. Therefore, in the design example described, the rear surface is spherical and the front surface is aspherical. However, if desired, more complex shapes can be employed to increase the match with the reference ray set.

To design this scleral lens:
a. A light source 1901a (typically placed at infinity), a corrective lens 1902 that is placed in front of the patient's eye to enhance the patient's vision, a three-dimensional model of the patient's anterior corneal surface 1903a, and the eye. Generate a first computer model (FIG. 19a) that includes a reference surface 1904a located posteriorly to the cornea.
b. Rays from the light source (1901a) are traced through the air to the anterior surface 1902F of the corrective lens 1902 using Snell's law.
c. By grasping the three-dimensional shape of the front surface (ray-incident surface) 1902F of the corrective lens, Snell's law is applied to the front air-lens boundary to determine the path of the light ray passing through the corrective lens 1902. ..
d. After grasping the three-dimensional shape of the rear surface (light emitting surface) 1902B of the correction lens, by applying Snell's law to the boundary between the rear surface and the air, the rays from the rear surface of the correction lens 1902 to the front surface 1903a of the cornea. Determine the route.
e. Determine the path of the light ray from the anterior surface 1903a of the cornea to the reference surface 1904a located in the eye. Knowing the three-dimensional shape of the anterior surface of the cornea, Snell's law is applied to the anterior air-corneal boundary and to any material boundary located in the eye between the cornea and the reference surface. The reference surface may be flat or curved. When the reference plane is placed in the cornea as depicted in Figure 19a, the only boundaries encountered are the air-corneal boundaries.
f. The path of the light rays traveling from the light source 1901a to the reference surface 1904a is stored, and this set of light rays is referred to as a reference ray set.
g. Generate a second computer model that includes the same light source 1901b, eye 1903b, and reference plane (1904b) as the first computer model (light source 1901b is the same as light source 1901a, eye 1903b is the same as eye 1903a). , Reference surface 1904b is the same as reference surface 1904a). The light source 1901b is placed at the same distance from the eye as the first computer model. The reference plane is placed in the eye at the same position as the first computer model.
h. In the second computer model (FIG. 19b), the eye is fitted with a scleral lens 1906, and the gap between the cornea and the posterior surface of the scleral lens is filled with fluid (typically saline) 1905. ..
i. From the reference ray set in the first computer model (FIG. 19a), insert a three-dimensional ray located between the cornea 1903a and the reference surface 1904a in the eye into the second computer model (FIG. 19b), The ray is placed in the eye 1903b at the same position as the first computer model. For the purpose of designing a scleral lens, here, a ray of light originates from the reference surface 1904b and goes out of the eye 1903b in the fluid 1905 and through the scleral lens 1906 from the front of the scleral lens to the light source 1901b. It is assumed that it is progressing.
j. The three-dimensional shape of the anterior surface 1903b of the cornea, the three-dimensional shape of the cornea-fluid interface, the refractive index of the cornea (typically 1.376), and the refractive index of the fluid (typically 1. 336) and then applying Snell's law to the corneal-fluid (saline) boundary, light rays pass from the anterior surface of the cornea through the fluid 1905 to the posterior surface of the scleral lens 1906. Determine the route to.
k. The height of the posterior surface of the scleral lens [reference numeral H2 (1107) in FIG. 11] is adjusted so as to cover the cornea (vault over). The vaulting height is not critical, but is typically less than 300 microns (micrometers).
l. In a second computer model, Snell's law was applied to the anterior (surface 2006F magnified in FIG. 20) and posterior surface (surface 2006B magnified in FIG. 20) of the scleral lens, and the sclera shown in FIG. 19b. The angle and position of the lens ray 1908b is snelled relative to the path traveled between the light source and the corrective lens of the reference ray set (1907a) in the first computer model as indicated by arrow 1908a in FIG. 19a. The three-dimensional shape of the anterior and posterior surfaces of the scleral lens optics is adjusted so that the approximation is as close as possible within the constraints imposed by the law. That is, 1908b≈1908a.

FIG. 21 is an enlarged view of the periphery of the cornea by superimposing the example of FIG. 19a and the example of FIG. 19b, and how much the rays in the design in the case of the scleral lens and the reference ray set in the configuration in the case of the correction lens It is an enlarged view showing whether they match. The light rays being drawn are incident on the eye at angles of about 0°, about 10° and about 20° with respect to a straight line orthogonal to the anterior surface of the cornea.

FIG. 22a is a three-dimensional representation of FIG. 19a, which is a first three-dimensional model required for a computer to design a scleral lens. FIG. 22b is a three-dimensional representation of FIG. 19b, which is the second three-dimensional model required for the computer to design the scleral lens.

FIG. 22c is a superposition of the example of FIG. 22a and the example of FIG. 22b and shows the degree of coincidence of the ray bundles, specifically, how much the scleral lens can reproduce the reference ray set. Is shown. In the design examples shown in FIGS. 19 to 22, the radius of curvature of the front surface 1902F of the correction lens 1902 of FIG. 19 is 150 mm, and the radius of curvature of the rear surface 1902B is 100 mm. In the scleral lens 2006 of FIG. 20, the spherical rear surface 2006B has a radius of curvature of 10.64 mm. The front surface of the scleral lens 2006 has a flat even surface (radius = 38,473 mm, conic = -4.75 mm, second order = 0.058, fourth order = 0.000623, sixth order = -0. 0001804, 8th-order term = 0.00003288, 10th-order term = -2.947E-6, 12th-order term = 1.06E-7). Each parameter used to specify an aspheric surface is described in Czajkowski, A., “Specifying an Aspheric Surface,” OPT 521-Report #2, December 14, 2007. There is.

Although there are many ray tracing programs and lens design programs on the market, the design shown in FIGS. 19 to 22 is a ray tracing called “Opticstudio” manufactured by Zemax LLC (Kirkland, WA, USA).・It was created by a lens design program.

(Design of scleral lens without vision correction optics)
In the above, the method of incorporating the corrective lens optical part in the scleral lens to eliminate the need for glasses, but in the following, although it does not require the corrective lens optical part or glasses to produce a clear image on the retina, Describes how to design a scleral lens for patients who want to wear a scleral lens for the purpose of alleviating dry eye symptoms or for some other reason.
FIG. 23a depicts a patient's eye focused on an object 2301a (typically located at an infinitely distant location). The subject is assumed to be clearly visible to the patient. In FIG. 23b, the case where the scleral lens 2304a is attached to the eye is depicted. The scleral lens must be designed so that, when applied to the eye, the visual acuity is maintained at the same level as before the application of the scleral lens. The goal is to project the same image as in Figure 23a onto the retina of Figure 23b, within the constraints of Snell's Law. With reference to Figures 24a and 24b, this can be achieved by matching the rays (2412a and 2412b) to the reference plane in the eye as previously described. The reference plane may be located anywhere in the eye posterior to the corneal surface (anterior, inward or posterior of the lens). In addition to matching the rays within the eye, the rays before and after application of the scleral lens are also matched outside the eye. Matching the light rays outside the eye corresponds to matching the reference light ray 2410a and the light ray 2410b. That is, the light ray 2410a≈the light ray 2410b and the light ray 2412a≈the light ray 2412b are set within the constraints imposed by Snell's law and the scleral lens manufacturing process. The second design example below describes the detailed steps required to design such a scleral lens.

Similar to the first example, the rear surface of the scleral lens is spherical and the front surface is aspheric. If desired, more complex shapes can be employed to improve the match with the reference ray set. To design the scleral lens above:
a. A light source 2501a (preferably placed at infinite distance), a patient's eye (2502a) according to a three-dimensional model of the anterior surface of the patient's cornea 2503a obtained from a shape analysis device, and the posterior cornea in the eye. Generate a first computer model (FIG. 25a) that includes the referenced surface 2504a.
b. Light rays from the light source (2501a) are traced through the air to the anterior surface 2503Fa of the cornea.
c. Determine the path of the light rays from the anterior surface 2503Fa of the cornea to the reference surface 2504a located in the eye. After grasping the three-dimensional shape of the anterior surface 2503Fa of the cornea supplied by the shape analysis device, Snell's law is applied to any material located between the anterior air-corneal boundary and the cornea in the eye and the reference surface 2504a. Apply to the border. The reference surface may be flat or curved.
d. The three-dimensional path of the light rays traveling from the light source 2501a to the reference surface 2504a is stored, and this set of light rays is referred to as a reference light ray set 2507a.
e. Generate a second computer model (FIG. 25b) that includes the same light source 2501b, eye 2502b, and reference plane (2504b) as the first computer model (light source 2501b is the same as light source 2501a, eye 2502b is eye 2502a). , The cornea 2503a is the same as the cornea 2503b, and the reference surface 2504b is the same as the reference surface 2504a). The light source 2501b is placed at the same distance from the eye as the first computer model. The reference surface 2504b is placed in the eye at the same position as the first computer model.
f. In a second computer model (FIG. 25b), the eye is fitted with a scleral lens 2506 and the gap between the cornea and the posterior surface of the scleral lens is filled with fluid (typically saline) 2505. ..
g. Of the reference ray set in the first computer model (FIG. 25a), the three-dimensional ray located between the cornea 2503a and the reference surface 2504a in the eye is inserted into the second computer model (FIG. 25b), The ray is placed in the eye 2503b at the same position as the first computer model. For the purpose of designing a scleral lens, here a ray of light originates from the reference surface 2504b, out of the eye 2502b, through the anterior surface 2503Fb of the cornea, through the fluid 2505b and through the scleral lens 2506, and in front of the scleral lens. Suppose that you are proceeding from.
h. The three-dimensional shape of the anterior surface of the cornea 2503b, the three-dimensional shape of the cornea-fluid interface, the refractive index of the cornea (typically 1.376), and the refractive index of the fluid (typically 1. 336), and applying Snell's law to the corneal-fluid (saline) boundary, light rays pass from the anterior surface 2503Fb of the cornea through the fluid 2505b to the posterior surface of the scleral lens 2506. Determine the route to reach.
i. The height of the posterior surface of the scleral lens [reference numeral H2 (1107) in FIG. 11] is adjusted so as to vault over the cornea. The vaulting height is not critical, but is typically less than 300 microns (micrometers).
j. In the second computer model, Snell's law is applied to the anterior surface (surface 2606F magnified in FIG. 26) and posterior surface (surface 2606B magnified in FIG. 26) of the scleral lens. This is because the ray 2508b shown in FIG. 25b between the anterior surface of the scleral lens and the light source is the path traveled by ray 2508a of FIG. 25a between the light source and the cornea of the reference ray set in the first computer model. It involves adjusting the three-dimensional shape of the anterior and posterior surfaces of the scleral lens optics so that they are as close to a maximum as possible within the constraints imposed by Snell's law on the path traveled. The matching operation of the ray 2508b with the ray 2508a stops at the front of the scleral lens.

FIG. 26 is an enlarged view of the periphery of the cornea by superimposing FIGS. 25a and 25b, and the rays in the design in the case of the scleral lens are the same as the reference ray set calculated without attaching the scleral lens to the eye. It is an enlarged view showing whether they agree with each other. The light rays being drawn are emitted at angles of 0°, 10°, and 20° from light sources placed at infinite distances.

FIG. 27a shows the actual first three-dimensional computer model used to calculate the reference ray set, where three ray bundles from an infinitely spaced source at infinity are zero. Emitted at angles of 10° and 20°. FIG. 27a is a three-dimensional drawing corresponding to the two-dimensional drawing shown in FIG. 25a.

FIG. 27b shows the actual second three-dimensional computer model used to design the scleral lens, where each ray bundle is 0°, 10° and 20° from an infinitely spaced source. Is emitted at an angle of. FIG. 27b is a three-dimensional drawing corresponding to the two-dimensional drawing shown in FIG. 25b.

Figure 27c is a superposition of Figures 27a and 27b and shows how a ray in the design for a scleral lens can reproduce the reference ray set. In the scleral lens design shown in FIGS. 25-27, the radius of curvature of its spherical back surface is 16.473 mm. Its front surface is a flat aspherical surface (radius=8,866 mm, conic=−0.053, second order=−1.727E-4, fourth order=1.251E-4, sixth order). =−6.553E-5, 8th order=9.107E-6, 10th order=−4.023E-7, 12th order=0.0).

Although there are many ray tracing programs and lens design programs on the market, the model shown in FIG. 25 to FIG. 27 is a rate called Optistudio manufactured by Zemax LLC (Kirkland, Washington, USA). It was created by a racing lens design program. Again, FIGS. 25 to 27 correspond to the actual design of the scleral lens.

(Manufacture of scleral lens)
Once the scleral lens optics, bearing surface shape, and vaulting height are determined, it is possible to manufacture the scleral lens as described above using a precision lathe or using a 3D printer. Become. An example of a precision lathe is Ametek Precitech, Inc. "Nanoform X" manufactured by Co., Inc. (Kean, NH, USA). An example of a precision 3D printer is the "Photonic Professional GT" manufactured by Nanoscribe GmBH (Eggenstein-Leopoldschafen, Germany).

In addition to the scleral lens described above in this specification, there are scleral lenses in which a soft material such as silicone hydrogel is incorporated as a material for the bearing surface. Such flexible materials follow the shape of the bearing area of the eye (often referred to as the "skirt"). The soft skirt of this followability supports a rigid optical lens that vaults over the cornea. As an example of a scleral lens having a soft skirt, SynergEyes, Inc. The products manufactured by the company (Carlsbad, California, USA) are listed.

The scleral lens optics designed using the techniques described herein can also be combined with a soft skirt or incorporated into a lens having a flexible bearing surface, thereby allowing It significantly reduces the time and complexity of designing a scleral lens.

(System implementation)
Figure 28 is a block diagram of a preferred embodiment of a system 2800 that may be used to implement the methods described herein.
In this example, a topographer 2810, a digital signal processor (DSP)/computer 2820, a display 2830, and a data storage 2840 are used to generate at least one three-dimensional model 2850 of the eye and/or the resulting lens. Processing and/or producing. The at least one model of lens can then be fed to precision lathe 2860 and/or 3D printer 2870. This creates a physical lens.

The shape analyzer 2810 may be one that obtains a 3D model of the eye using a video camera and line scan device, as described in the previously cited US Pat. No. 9,398,845 by Bishop et al. Another shape analyzer described in Bishop et al., US Pat. No. 9,489,753, cited above, uses optical coherent topography to measure eye topology. In addition, there is also a shape analyzer that determines the shape of the cornea by projecting a pattern on the eye and measuring the pattern distortion, such as a Placido Disc shape analyzer. Some other shape analyzers determine the shape of the eye by inserting a fluorescent dye into the eye and projecting a pattern onto this fluorescent material. For the application described herein, any shape analysis device that corrects for eye movement during scanning and provides a motion-compensated blur free topology. May be used. Based on the above, the shape analysis device 2810 includes a plurality of constituent elements (such as a two-dimensional (2D) digital video camera for capturing a series of images of the eye including at least one feature on the eye). (Not shown in detail). The camera can be a television camera or other digital camera capable of capturing a series of images. The shape analyzer 2810 also includes a scanner for measuring the distance to the surface of the eye and generating a plurality of independent sets of measurement data points in 3D space. In this way, each "pixel" of the series of camera images is associated with an x,y,z position on the surface of the eye.

The DSP/computer 2820 may also include storage 2840 and/or display 2830 and/or other peripherals.
The DSP/computer 2820 executes program code to perform some or all of the method steps described herein for determining a lens design.
The at least one 3D model 2850 defining the lens design can then be provided as an output data file to a lens manufacturing machine (or process) such as a precision lathe 2860, 3D printer 2870.

It should be understood that numerous other arrangements of programmable and/or computer controlled components are possible. For example, the DSP/computer 2820 illustrated here may function as both a computer for the shape analyzer and a platform for performing the lens design methods described herein. In another arrangement, the shape analyzer 2810 itself may comprise a DSP and/or computer arranged to process the output of the camera and of the scanner to generate eye topology data points. The lens design procedure may be executed by a DSP/computer different from the lens design procedure. The eye scan data from the shape analysis device may be transmitted to the lens design computer in the form of a data file via a network, or a memory stick, a disk, a magnetic tape, or the like can be carried. It may be carried by any storage medium. Precision lathe 2860 and/or 3D printer 2870 may typically have their own processor and may be located remotely from DSP/computer 2820. In that case, the precision lathe 2860 and/or the 3D printer 2870 is transmitted to the precision lathe 2860 and/or the 3D printer 2870 in the form of a data file, or is a portable storage medium such as a disk or a magnetic tape. Can process the design of the 3D model provided to the precision lathe 2860 and/or the 3D printer 2870 at. In addition, the DSP/computer may directly control a precision lathe 2860 and/or a 3D printer 2870, which is located near or at a remote place, via a network connection. Still other arrangements are possible.

(Conclusion)
From the above, a method of determining at least one characteristic of a lens design is a step of receiving an array of a plurality of data points from an eye shape analyzer, and extracting at least a three-dimensional position of each data point from the array. It is to be understood that there may be steps that can be performed. The data points are such that each data point represents an independent x, y, z measurement position on the surface of the eye, and the spatial relationship between the data points represents the actual topology of the eye. Not to include motion blur artifacts that occur during point acquisition, to be accurately reflected, and the sampling density of the data points is set to be high enough to characterize the eye abnormality. There is. The method then proceeds to analyzing the data points and determining an array of independent data points to define a posterior surface of the lens. The resulting lens becomes a contact lens that follows or covers the anomaly in the eye.

In some aspects, the data points further comprise a plurality of independent data points used from the shape analysis device or determined to define the posterior surface of the lens. Can be used to group together, the meridians are independent of each other, and the density of the meridian data points characterizes any abnormality in the eye that compromises the comfort or fit of the lens. High density enough for.

The method also includes the step of determining at least one characteristic of a design of a lens having an anterior surface and a posterior surface: receiving an array of data points from an eye shape analyzer, the array comprising: , At least a three-dimensional position of each data point can be extracted, and each data point used from the shape analyzer represents x, y, z measurement positions independent of each other on the surface of the eye. The spatial relationship between the data points utilized by the shape analysis device accurately reflects the actual topology of the eye without including motion blur artifacts that occur during acquisition of the data points. And the sampling density of the data points utilized from the shape analyzer is high enough to characterize the eye abnormality that reduces lens comfort and fit.
From the data points used by the shape analyzer, a lens back surface having a boundary of a quadrant or a sub-division area (sub-division) defined by a number of independent data points is determined, and the quadrant or the area within the quadrant is determined. There are additional independent data points that are not used to define the boundary, and the density of independent data points within each quadrant or region within the quadrant determines the comfort and fit of the lens. A high enough density to characterize anomalies everywhere in the quadrant or in the quadrant that can be reduced, and the resulting lens is a contact lens that follows the anomaly in the eye or covers the anomaly. is there.

The method also includes the step of determining at least one characteristic of the lens design,
A step of receiving an array of a plurality of data points from the eye shape analysis device,
From the array, at least a three-dimensional position of each data point of the eye can be extracted;
Determining a characteristic of the lens, the characteristic comprising: an optical region, a transition region and a bearing surface; and
The optical region is a region that images incident light into the eye, the transition region is a region that connects the optical region to the bearing surface, and the bearing surface is the eye of the lens. The bearing surface is defined as an array of a plurality of independent data points that match the positions of the three-dimensional data points of the eye extracted from the shape analysis device, including the area to be placed on the surface. The resulting lens is a scleral lens that follows or is vaults over the anomaly at any location in the eye, and the lens optical portion within the optical region is the optical portion. Overlying the cornea of the eye to form a fluid pool between the posterior surface and the cornea, the bearing surface resting only on the sclera and following the three-dimensional shape of the sclera, or Alternatively, the corneal rim is partially placed on the three-dimensional shape of the sclera to follow the three-dimensional shape and at the same time partially placed on the three-dimensional shape of the cornea to follow the three-dimensional shape. Straddling, the bearing surface is lowered at least one trough and/or in the naturally occurring topology of the eye below the lens bearing surface so that tears can freely flow into and out of the area covered by the lens. It includes at least one raised gap formed on the bearing surface, and the trough or gap forms an excessive suction suction between the lens and the eye that makes removal of the lens difficult. It is also prevented.

The method also includes determining at least one characteristic of the design of the lens optics without applying a trial lens to the patient's eye: the light source, the anterior corneal surface of the patient's eye provided by a shape analyzer. Generating a first computer model including an eye having a three-dimensional model and a reference surface located posterior to the anterior corneal surface in the eye, wherein the reference surface may be planar or curved. , Process,
Inserting a corresponding corrective lens between the light source and the eye in the first computer model when the patient requires corrective lenses or glasses to produce a clear image on the retina. ,
Tracing light rays from the light source through the air to the front surface of the corrective lens;
Determining the path of the ray within the corrective lens by using the three-dimensional shape of the front surface of the corrective lens and applying Snell's law to the front air-lens boundary; and
When the light rays travel from the posterior surface of the corrective lens to the anterior surface of the cornea by using the three-dimensional shape of the posterior surface of the corrective lens and applying Snell's law to the posterior lens-air boundary. Determining the path of said rays of
The first computer passes light rays from the light source through the air to the anterior surface of the cornea when the patient does not need corrective lenses or glasses to produce a clear image on the retina. Direct tracing without inserting a corrective lens into the model,
Determining the path of the light beam from the anterior surface of the cornea to a reference surface located in the eye, using the three-dimensional shape of the anterior surface and the reference surface of the cornea and an anterior air-corneal boundary and Applying Snell's law to any material boundary located between the cornea and the reference surface in the eye;
Storing the path of the light rays traveling from the light source to the reference surface as a reference light ray set,
A second computer model including the same light source, eye, and reference plane as the first computer model is disposed at the same distance from the eye as the first computer model, and the reference plane is the eye. Generating by locating in the same position as the first computer model and further in the second computer model,
In the second computer model, mounting a scleral lens on the eye and filling a gap between the cornea and the posterior surface of the scleral lens with a fluid model;
Of the reference ray set in the first computer model, a ray portion located between the cornea and the reference surface in the eye is inserted into the second computer model, and the ray portion is inserted into the eye. In the same position as the first computer model in.

In the second computer model, when the light ray travels outside the eye with the reference surface as a starting point, the method further includes the three-dimensional shape of the anterior surface of the cornea and the refraction of the cornea. Index and the index of refraction of the fluid and applying Snell's law to the corneal-fluid boundary such that the rays pass from the anterior surface of the cornea through the fluid to the posterior surface of the scleral lens. Determining the path of the ray as it travels,
If the first computer model includes a corrective lens, Snell's law is applied to the anterior and posterior surfaces of the scleral lens optic to identify the reference ray set in the first computer model. Over the common area between the light source and the corrective lens, the ray in the second computer model and the ray in the first computer model are the closest approximations within the constraints defined by Snell's law. Adjusting the three-dimensional shape of the front and back surfaces of the lens,
If the first computer model does not include a corrective lens, Snell's law is applied to the anterior surface and posterior surface of the scleral lens optic to apply the strong lens in the second computer model. The ray in the second computer model and the reference ray portion in the first computer model are approximated within a constraint defined by Snell's law over a common region defined by the distance between the front surface of the film lens and the light source. Adjusting the three-dimensional shape of the front surface and the rear surface of the lens.

In view of the above, it should be understood that the present patent application is limited only by the appended claims.

Claims (7)

A method of designing and manufacturing a lens having a front surface and a rear surface,
a. Operating an eye shape analyzer that provides a three-dimensional model of the eye, designated as an array of pixel data points, the array of pixel data points including at least three-dimensional (3D) positions of each pixel data point; Prepare,
b. Each pixel data point represents an x, y, z position on the surface of the eye and the corresponding intensity value of each pixel data point,
c. The space between the pixel data points in the 3D model is corrected after correcting the clinically visible anomaly in the eye for artifacts caused by impulsive eye movements and random eye movements that occur during the acquisition of the pixel data points. Accurately reflects the physical relationship,
d. The sampling density of the pixel data points used by the shape analysis device characterizes at least one of the clinically visible abnormalities in the eye and also characterizes at least one of a pupil, an iris, and a blood vessel. High density,
The method further comprises
e. A step of determining an array of a plurality of independent data points for defining the posterior surface of the lens from the data points used by the shape analyzer.
The density of these independent data points defining the posterior surface of the lens is sufficiently high to allow adjustment of the posterior surface of the lens in response to the anomaly in the eye,
f. The method wherein the resulting lens is a contact lens that adapts to or masks the abnormality in the eye. The method of claim 1, further comprising:
g. 3D printing or machining the contact lens using the design,
And the process is
Including sub-steps for determining characteristics of the lens, including an optical zone, a transition zone and a bearing surface,
The optical region is a region that images incident light into the eye, the transition region is a region that connects the optical region to the bearing surface, and the bearing surface is the eye of the lens. Including the area to be placed on the surface,
The resulting lens is a scleral lens that adapts to or covers the anomaly, and the lens optics in the optic region have a fluid pool between the posterior surface of the lens optic and the cornea. Overlying the cornea of the eye to form, the bearing surface (i) rests only on the sclera and follows the three-dimensional shape of the sclera, or (ii) the sclera The bearing surface is partially placed on a three-dimensional shape and follows the three-dimensional shape, and also partially placed on the three-dimensional shape of the cornea and straddles the corneal edge so as to follow the three-dimensional shape and the bearing surface. Is deliberately raised from at least one location below the lens bearing surface of the eye topology and/or at least one embossment so that tears can freely flow into and out of the area covered by the lens. A method in which an up clearance is formed in the bearing surface. The method of claim 2, further comprising:
A step of determining a lens rear surface from the data points used from the shape analysis device, wherein a quadrant of the lens rear surface or a boundary of an area within the quadrant is defined by a plurality of independent data points, and each quadrant or quadrant is defined. There are additional independent data points in the inner area that are not used to define the boundary, and the density of independent data points in each quadrant or in the quadrant is such that the quadrant or quadrant A process that is dense enough to characterize anomalies everywhere in the inner region,
Comprising a method. The method of claim 1, wherein the 3D model is such that artifacts caused by impulsive eye movements and random eye movements are further corrected by additional steps. ,
Providing the 3D position information from multiple scans of a 3D scanner,
Providing the corresponding intensity value from a 2D camera image that is imaged in each scan process of the 3D scanner and converted into the 3D model, and the intensity value from the 2D image to a position within the 3D model. Maintaining a spatial relationship between the 3D scanner and the 2D camera to enable accurate mapping to the 2D image of the 2D image provided by the 2D camera. The intensity value represents at least one of the clinically visible abnormalities in the eye and characterizes at least one of a pupil, an iris, and a blood vessel;
Is the way. The method of claim 1, wherein the 3D model of the eye is obtained in additional steps, the steps comprising:
A step of generating a plurality of 3D models in each of two or more gaze directions, the plurality of 3D models each including an array of pixel data points, each pixel data point corresponding to an x, y, z position and a corresponding A process including corresponding intensity values derived from a 2D video camera image,
Identifying at least one visual feature common to at least two of the 3D models, and splicing the 3D models together at the x, y, z positions.
Is the way. A method of designing and manufacturing a lens including at least one characteristic of a lens optic portion without applying a trial lens to a patient's eye, the method comprising:
a. Creating a first computer model including a light source, an eye having a three-dimensional model of an anterior corneal surface of the patient's eye provided by a shape analyzer, and a reference plane located posterior to the anterior corneal surface in the eye. And
In the three-dimensional model, the positions of the three-dimensional data points of the eye are extracted from the shape analysis device, and the reference surface arranged in the anterior surface of the cornea in the eye, the reference surface is a flat surface or a curved surface. A process, which can be
i. Where the patient requires corrective lenses or glasses to produce a clear image on the retina,
Inserting a corresponding corrective lens between the light source and the eye in the first computer model;
Tracing light rays from the light source through the air to the front surface of the corrective lens;
Determining the path of the ray within the corrective lens by using the three-dimensional shape of the front surface of the corrective lens and applying Snell's law to the front air-lens boundary; and
When the light rays travel from the posterior surface of the corrective lens to the anterior surface of the cornea by using the three-dimensional shape of the posterior surface of the corrective lens and applying Snell's law to the posterior lens-air boundary. Determining the path of said rays of
ii. The first computer passes light rays from the light source through the air to the anterior surface of the cornea when the patient does not need corrective lenses or glasses to produce a clear image on the retina. Direct tracing without inserting a corrective lens into the model,
iii. Determining the path of the light beam from the anterior surface of the cornea to a reference surface located in the eye, using the three-dimensional shape of the anterior surface and the reference surface of the cornea and an anterior air-corneal boundary and Applying Snell's law to any material boundary located between the cornea and the reference surface in the eye;
iv. Storing the path of the light rays traveling from the light source to the reference surface as a reference light ray set,
b. A second computer model including the same light source, eye, and reference plane as the first computer model is disposed at the same distance from the eye as the first computer model, and the reference plane is the eye. In the second computer model by creating a second computer model by placing the first computer model in the same position in the second computer model; i. In the second computer model, mounting a scleral lens on the eye and filling a gap between the cornea and the posterior surface of the scleral lens with a fluid model;
ii. Of the reference ray set in the first computer model, a ray portion located between the cornea and the reference surface in the eye is inserted into the second computer model, and the ray portion is inserted into the eye. Locating the same position as the first computer model in
iii. In the second computer model, it is assumed that the light ray travels outside the eye with the reference surface as a starting point, and the three-dimensional shape of the anterior surface of the cornea, the refractive index of the cornea, and the fluid By using Snell's law for the corneal-fluid boundary using the index of refraction, the ray as it travels from the anterior surface of the cornea through the fluid to the posterior surface of the scleral lens. Determining the path of the light beam,
iv. If the first computer model includes a corrective lens, Snell's law is applied to the anterior and posterior surfaces of the scleral lens optic to identify the reference ray set in the first computer model. Over the common area between the light source and the corrective lens, the ray in the second computer model and the ray in the first computer model are the closest approximations within the constraints defined by Snell's law. Adjusting the three-dimensional shape of the front and back surfaces of the lens,
v. If the first computer model does not include a corrective lens, Snell's law is applied to the anterior surface and posterior surface of the scleral lens optic to apply the strong lens in the second computer model. The ray in the second computer model and the reference ray portion in the first computer model are approximated within a constraint defined by Snell's law over a common region defined by the distance between the front surface of the film lens and the light source. Adjusting the three-dimensional shape of the front surface and the back surface of the lens,
And the lens optical portion is incorporated in the optical region of the scleral lens, the method further comprising:
Determining the characteristic of the scleral lens, the characteristic including an optical region, a transition region and a bearing surface, the optical region being a region that images incident light into the eye, The transition area is an area connecting the optical area to the bearing surface, the bearing surface includes an area of the lens placed on the surface of the eye, and the bearing surface further includes the shape analysis. Defined as an array of independent data points that match the position of the three-dimensional data points of the eye extracted from the device, each data point utilized from the shape analysis device is on the surface of the eye. Representing x, y, z measurement positions independent of each other, the spatial relationship between the data points utilized from the shape analyzer is based on the actual topology of the eye, the impulsiveness that occurs at the time of acquisition of the data points. It accurately reflects after correcting the artifact or the motion blur artifact, and the sampling density of the data points used from the shape analyzer and the sampling density of the data points on the bearing surface of the lens are At a density high enough to characterize anomalies everywhere in the resulting lens is a scleral lens that follows or covers the anomalies anywhere in the eye. An inner lens optic portion is covered on the cornea of the eye to form a fluid pool between the posterior surface of the optic portion and the cornea, and the bearing surface is (i) resting only on the sclera. To follow the three-dimensional shape of the sclera, or (ii) partially placed on the three-dimensional shape of the sclera to follow the three-dimensional shape and partially to the three-dimensional shape of the cornea. The lens of the eye topology is placed such that it straddles the corneal rim to follow the three-dimensional shape and the bearing surface allows tears to freely flow into and out of the area covered by the lens. Intentionally raised from at least one point below the bearing surface and/or at least one raised gap is formed in the bearing surface;
3D printing or machining the contact lens using the design;
Comprising a method. 7. The method of claim 6, wherein the reference surface is posterior to the cornea.

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