CN115016146A

CN115016146A - Method and trial set for scleral contact lens fitting

Info

Publication number: CN115016146A
Application number: CN202210854663.4A
Authority: CN
Inventors: 不公告发明人
Original assignee: Fitland Ltd; Zhuhai Fitland Medical Technology Co ltd
Current assignee: Fitland Ltd; Zhuhai Fitland Medical Technology Co ltd
Priority date: 2022-07-17
Filing date: 2022-07-17
Publication date: 2022-09-06

Abstract

The present invention relates to a method and set of trial lenses for fitting a scleral contact lens to a subject, the scleral contact lens comprising an optical zone disposed at the center of the lens, the optical zone having a base curve radius of curvature BCR, a transition zone surrounding the optical zone, the transition zone having a transition zone radius of curvature TZR, and a landing zone disposed at the periphery of the lens, the landing zone having a landing zone radius of curvature LZR, wherein TZR is BCR dependent but LZR is independent of BCR. The method comprises the following steps: measuring corneal morphology of the subject to obtain a Flat K (FK) value and a corneal eccentricity e value corresponding to the FK value of the cornea of the subject; selecting a first try-on piece of the scleral contact lens for the subject based on the FK value and the e value. The set of fitting sheets includes at least two subgroups having different LZR, each subgroup containing a plurality of fitting sheets having different BCR. The method and the trial wearing plate set are simple and easy to operate, and the time for the fitting of the scleral contact lens can be greatly shortened.

Description

Method and trial set for scleral contact lens fitting

Technical Field

The invention relates to the field of contact lenses, in particular to a method for fitting a scleral contact lens and a fitting sheet set.

Background

Scleral contact lenses are large diameter rigid gas permeable contact lenses commonly used for daytime wear. In contrast to conventional rigid oxygen permeable contact lenses (RGPs), scleral lenses land on the sclera and arch across the cornea and at the corneal/scleral junction, known as the limbus, thus enabling the formation of a gap between the posterior surface of the lens and the anterior surface of the cornea and the limbus, the posterior lachrymal space (posteror lens clear). The retrospecularly lachrymal space includes the corneal space and the corneoscleral margin space. The gap is used as a liquid storage, which can be filled with tears, physiological saline or functional solution such as liquid medicine, etc., can create an ideal ocular surface environment, and has incomparable advantages for protecting cornea and corneoscleral marginal tissues, improving eye dryness, correcting irregular astigmatism of cornea, reducing higher order aberration, etc.

Scleral contact lenses typically include an optic zone, a transition zone, and a landing zone. The optical zone is located in the center of the lens and is primarily used for vision correction. The landing zone is the outermost peripheral region of the scleral contact lens and is also the weight bearing area of the entire lens. The transition zone connects the optical zone and the landing zone, typically arching over the corneoscleral rim.

The fitting of scleral contact lenses requires consideration of a number of factors, including ensuring that the lens has a proper post-lens tear clearance when worn on a human eye, does not contact the cornea and the corneal limbus, does not have large bubbles, does not compress blood vessels, is comfortable to wear, and the like. Most scleral contact lens formulations require the measurement of a variety of ocular parameters for comfort and are typically designed with a variety of lens parameters to adjust the shape of the posterior surface of the scleral contact lens, particularly the posterior surface of the landing zone, to the eye topography of the subject in order to maximize the fit of the lens eye. Therefore, most scleral contact lenses are complicated to fit and require a long time to evaluate when the lens is worn for 20-30 minutes, 2 hours, and 4 hours.

Thus, there remains a need for a scleral contact lens that is simple in design, simple to fit, and easy to wear.

Disclosure of Invention

The present invention relates to a method of fitting a scleral contact lens for a subject, the scleral contact lens comprising an optical zone disposed at the center of the lens, a blend zone surrounding the optical zone, the optical zone having a base curve radius of curvature BCR, the blend zone having a blend zone radius of curvature TZR, and a land zone disposed at the periphery of the lens, the land zone having a land zone radius of curvature LZR, wherein TZR is BCR dependent but LZR is independent of LZRBCR, the method comprising: measuring corneal morphology of the subject to obtain a Flat K (FK) value and a corneal eccentricity e value corresponding to the FK value of the cornea of the subject; and selecting a first fitting sheet of the scleral contact lens for the subject based on the FK value and the e value, the first fitting sheet having an optical zone with a first base curve radius BCR ₁ And its landing zone has a first landing zone radius of curvature LZR ₁ 。

In some embodiments, the step of selecting the first try-on piece comprises: calculating a lens rise from the FK value, the e value, and a target initial vertex gap; calculating a theoretical base arc curvature radius from the lens rise and base arc eccentricity; and subtracting a correction parameter C from the calculated theoretical base arc curvature radius to obtain the first base arc curvature radius BCR ₁ Wherein the target initial vertex gap is 40-200 μm, the base arc eccentricity is 0.30-1.10, and the correction parameter C is 0.2-0.5.

In some embodiments, the BCR is selected from 5.0mm to 14.0 mm; and/or the TZR is 0.0-2.0 mm larger than the BCR; and/or the LZR is greater than the BCR and is independently selected from 8.5-15.0 mm.

In some embodiments, the method further comprises: fitting the first fitting piece 20-30 minutes after the subject wears the first fitting piece, wherein if the first fitting piece is well fitted, the subject is customized to have the BCR ₁ And LZR ₁ The scleral contact lens of (a); selecting a BCR with a second base arc radius of curvature for the subject if the first fitting is not well-fitted ₂ And/or secondary landing zone radius of curvature LZR ₂ And performing fitting evaluation again 20-30 minutes after the subject wears the second fitting sheet, wherein BCR ₂ Is different from BCR ₁ ，LZR ₂ Other than LZR ₁ 。

In some embodiments, the fitness evaluation comprises: the apical gap and/or the corneoscleral edge gap are measured.

In some embodiments, measuring the subject's corneal morphology is by corneal topography measurement, and preferably, the method comprises performing a plurality of corneal topography measurements.

The present invention also relates to a set of trial lenses for fitting of a scleral contact lens, the trial lens being a scleral contact lens and comprising an optical zone disposed in the center of the lens, the optical zone having a base curve radius BCR, a blend zone surrounding the optical zone, the blend zone having a blend zone radius of curvature TZR, and a land zone disposed on the periphery of the lens, the land zone having a land zone radius of curvature LZR, wherein TZR is BCR dependent but LZR is independent of BCR, the set of trial lenses comprising: the high-edge warping subgroup containing a plurality of first test wearing pieces and the low-edge warping subgroup containing a plurality of second test wearing pieces, wherein the curvature radiuses of the landing areas of the first test wearing pieces are the first curvature radiuses LZR of the landing areas ₁ And the curvature radiuses of the landing areas of the plurality of second try-on pieces are all the second curvature radiuses LZR of the landing areas ₂ Wherein LZR ₁ Greater than LZR ₂ And LZR ₁ And LZR ₂ Each independently selected from 8.5-15.0 mm; and the plurality of first try-on pieces have different base arc curvature radiuses, the plurality of second try-on pieces have different base arc curvature radiuses, the base arc curvature radiuses of the first try-on pieces and the second try-on pieces are all selected from the same base arc curvature radius set, and the base arc curvature radius set comprises a plurality of preset base arc curvature radiuses which are distributed in an equal step mode and are selected from 5.0-14.0 mm.

In some embodiments, the number of the first try-on pieces is the same as the number of the second try-on pieces.

In some embodiments, the number of the preset base arc curvature radii is the same as the number of the first try-on pieces and/or the number of the second try-on pieces.

In some embodiments, the set of try-on pieces further comprises a material having a composition other than LZR ₁ And LZR ₂ Other subgroups of LZR.

Drawings

Fig. 1 schematically illustrates a cross-sectional view of a scleral contact lens according to the present invention placed on a human eye.

Fig. 2 is a schematic diagram of a scleral contact lens, according to one embodiment of the present invention. The left figure is a bottom view of the scleral contact lens; the right drawing is a sectional view of the left drawing taken along the line A-A.

FIG. 3 is a fluorescence pixel rendering image evaluated using a slit-lamp cobalt blue diffuse light source.

FIG. 4 is a schematic diagram of landing zone edge warp estimation.

Fig. 5 is a flow chart of a scleral contact lens fitting method according to the present invention.

Reference numerals:

OZ: an optical zone; TZ: a transition zone; and (3) LZ: a landing zone; TD: the total lens diameter; AC: a vertex gap; LSH: the lens rise; ESH: eye rise; EL: edge warping; j1: the optical zone and transition zone back surface junction; j2: a transition zone and landing zone rear surface junction; 1: a cornea; 2: the bulbar conjunctiva.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. Numerous specific details are set forth in the following description in order to provide a thorough and complete disclosure of the present invention and to fully convey the concept of the present invention to those skilled in the art. With respect to the drawings, the relative proportions and proportions of features in the drawings may be exaggerated or reduced in size, for the sake of clarity and convenience. Such arbitrary proportions are merely illustrative and do not limit the invention in any way. Unless otherwise defined, terms used in the present application have meanings commonly understood by those skilled in the art.

When described in this application in connection with a contact lens, "anterior surface" refers to the surface that is proximate to the inner surface of the eyelid when worn, or the convex surface of the lens; "posterior surface" refers to the side of the lens that faces the cornea when worn, or the concave surface of the lens.

First, sclera contact lens

The present invention relates to a simple design scleral contact lens, as shown in fig. 1, comprising an Optic Zone (OZ) having a base curve radius of curvature BCR, a Transition Zone (TZ) having a transition zone radius of curvature TZR, and a Landing Zone (LZ) having a landing zone radius of curvature LZR, wherein TZR is BCR dependent but LZR is independent of BCR. The optic zone is centered in the lens and is generally larger in diameter than the horizontal visible iris diameter, primarily for vision correction. The landing zone is the outermost peripheral region of the scleral contact lens, which is the region where the scleral contact lens contacts or lands on the ocular surface. The transition zone connects the optical zone and the landing zone, typically arching over the corneoscleral rim. In the scleral contact lens, the curvature radius of the transition area is linked with the curvature radius of the base arc, the target curvature radius of the base arc can be selected and the corresponding curvature radius of the transition area can be determined at the same time by measuring the cornea form of a subject, and the curvature radius of the landing area is adjusted by the matching condition of the landing area, so that the proper lens parameters can be selected.

The scleral contact lenses of the present invention are open or non-enclosed scleral contact lenses. As used herein, an "unsealed" or "open" scleral contact lens means that the posterior surface of the scleral contact lens 'land area is not designed or customized to be fully or as closely complementary or fit to its wearer's corresponding ocular surface topography as is conventional closed or semi-closed scleral contact lenses.

Because a perfect fit to the ocular surface (bulbar conjunctiva portion) is not sought, the scleral contact lens of the present invention, the posterior surface of which is rotationally symmetric, and in particular the landing zone thereof, is simple in design. In some embodiments, the rear surface of the landing zone is rotationally symmetric aspheric. In some embodiments, the aspheric surface has an eccentricity of 0.05 to 1.00, preferably 0.05 to 0.60.

Other features of the scleral contact lens of the present invention include: higher ocular surface mobility, thin posterior tear space, and the like, as will be described in more detail below.

(I) Lens moving (movement)

The landing zone is the outermost peripheral region of the scleral contact lens and is also the load bearing area of the entire lens, and in order to improve comfort, avoid conjunctival compression and distribute the weight of the lens as much as possible, it is generally required that the posterior surface of the landing zone conforms to the corresponding ocular surface shape as much as possible to have a larger area of contact area. It has been shown that the shape of the anterior surface of the sclera (between 15.0mm and 20.0mm in diameter) is tangential in most subjects, exhibiting a convex shape in less than one third of the subjects, and a very small proportion of subjects having a concave shape. Furthermore, it is known in the art that the shape of the anterior surface of the sclera increases in asymmetry in areas other than 13.0mm in diameter. Therefore, to achieve good fit and lens stability, most scleral contact lenses are designed with a posterior surface profile of the land area that is tangential with little or no curvature, and many have attempted to divide the scleral contact lens into multiple zones or quadrants in order to adjust the parameters and design of the scleral contact lens within the various zones based on the ocular topography of the subject.

Because of this, most scleral contact lenses are closed or semi-closed with little or no tear exchange and lens mobility. In most cases, an ideally suited conventional scleral contact lens would not exhibit any clinically significant tear exchange without mechanical manipulation. Complications that may be readily induced by closed scleral contact lenses include, but are not limited to, daytime fogging caused by tear pool debris, visual fluctuations caused by lens sedimentation, off-center induced higher order aberrations, high lipid concentrations, inflammatory factor accumulation, corneal hypoxic stress, and the like. In addition, because conventional scleral contact lenses have no or only minimal tear fluid exchange, the reservoir of the lens cannot be filled, resulting in the formation of air bubbles, etc., after wearing, and thus, during wearing, the wearer is required to add a suitable liquid to the concave surface of the lens in advance, lower the head substantially parallel to the ground, and then place the scleral contact lens with the liquid in the eye with one hand. If the amount of liquid added is insufficient or the wearing is not skilled, air bubbles may exist between the lens and the ocular surface, and therefore the lens needs to be removed and worn again because air bubbles cause discomfort to the eye, blurred vision and corneal staining, which are avoided by scleral contact lenses both when and during the wearing of the lenses.

Accordingly, in embodiments of the present invention, the inventors have solved the problems associated with conventional closed/semi-closed scleral contact lenses by providing an open or closed scleral contact lens. As used herein, an "unsealed" or "open" scleral contact lens means that the posterior surface of the scleral contact lens 'land area is not designed or customized to be completely or as closely complementary or fit to its wearer's corresponding ocular surface topography as possible.

Because perfect conformity to the ocular surface topography is not sought, the scleral contact lenses of the present invention have a higher degree of ocular surface movement than comparable products. The higher the lens mobility, the higher the tear exchange rate. The scleral contact lenses of the present invention have been shown to provide continuous dynamic tear exchange, which is manifested, for example, by the observation that fluorescein fills the back of the lens after 5-10 blinks after dropping fluorescein over the lens. However, a degree of movement that is either too high or too low can reduce comfort, and thus in some embodiments, scleral contact lenses of the present invention are configured to have a degree of movement on the surface of the eyeball during use that is between 0.4mm and 1.2mm, preferably between 0.5mm and 1.0mm, such as between about 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1mm, and any value therebetween, preferably less than 1.0mm, and more preferably about equal to 0.5mm (e.g., 0.5 ± 0.05 mm). The degree of movement is measured by slit lamp illumination (0.5-2.0mm width) and a known length of the slit lamp graduation line or slit lamp illumination beam width, and the movement of the lens is evaluated using the direct focus method.

In some embodiments, the posterior surface of the landing zone of the scleral contact lens of the present invention is rotationally symmetric about the optical axis of the scleral contact lens, and therefore does not fit perfectly when the lens is placed on the sclera with an asymmetric anterior surface topography, but rather is likely to have only a few points or locations of contact, thereby providing greater mobility and facilitating sub-lens tear exchange. In still other embodiments, the rear surface of the landing zone is rotationally symmetric aspheric.

In still other embodiments, the perpendicular distance of the junction of the posterior surface of the landing zone and the posterior surface of the transition zone (i.e., the starting point of the landing zone, J2) from the lens axis of the scleral contact lens is between 6.0mm and 7.0mm, preferably between 6.0mm and 6.8mm, such as 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7mm and any value therebetween, to take full advantage of the asymmetry of the anterior surface of the sclera beyond 13.0mm in diameter.

Without wishing to be bound by any theory, the inventors believe that the scleral contact lens of the present invention solves the problems of the prior art by effectively avoiding the accumulation of proteins, lipids, mucins and inflammatory factors within the tear layer between the cornea and the posterior surface of the lens by achieving adequate exchange of tears beneath the scleral contact lens with tears outside the lens.

As mentioned above, conventional scleral contact lenses are typically designed to be closed or semi-closed reservoirs, and thus are also particularly suitable for dry eye patients. However, the biggest problem with closed or semi-closed scleral contact lenses is the accumulation of various chemicals and debris in the tear layer under the lens, and daytime fogging (midday fogging) is one of the most representative manifestations, which makes the subject have to take the lens off for cleaning during the day's wearing to maintain good vision. The scleral contact lens of the present invention does not perfectly conform to the ocular surface in the landing zone, has a relatively high mobility, can achieve the filling of the tear pool behind the lens and the continuous exchange and renewal of tears by means of the blinking action of the subject, is beneficial to the corneal health, and enables the lens to be worn comfortably for a whole day without any problems.

Therefore, the scleral contact lens does not need to drip physiological saline before wearing, is simple to wear, has no fogging phenomenon in the daytime, and is safe and convenient to pick.

(II) corneal space

When placed on the eyeball, the scleral contact lens of the present invention forms a reservoir space by having the posterior surface of neither the optic zone nor the transition zone in contact with the anterior surface of the eyeball of the subject. The gap between the posterior surface of the optical zone and the anterior surface of the cornea is called the corneal gap, and the gap between the posterior surface of the transition zone and the anterior surface of the corneal limbus is called the corneal limbus gap. The corneal space may be characterized by a central or apical space (ac). The central space is the distance between the center of the posterior surface of the scleral contact lens and the anterior surface of the cornea; the apex gap is the distance between the highest point of the anterior surface of the cornea and the posterior surface of the scleral contact lens. Since the anterior corneal topography is generally irregular, particularly for keratoconus patients, corneal trauma or post-corneal surgery patients, the apex gap is used in the present invention to determine whether the scleral contact lens vault over the cornea is appropriate. The apex gap is related to the Lens Sagittal Height (LSH) (i.e., the perpendicular distance between the geometric center of the lens back surface and the plane of the lens edge).

The corneal space must not be too large nor too small. When the corneal space is too large, the tear layer therein increases in thickness, affecting the transmission of oxygen from the outer surface of the lens to the cornea, easily resulting in hypoxia of the cornea and, at the same time, accumulation of various ocular debris (e.g., mucosal debris (mucosis), meibomian gland debris (meibomian debris), lacrimal debris). In the case of insufficient corneal space, due to the sedimentation effect of the scleral contact lens, it is possible that the contact of the posterior surface of the scleral contact lens with the anterior surface of the cornea occurs after the subject wears the lens for several hours, causing damage to the corneal epithelium. Furthermore, even if corneal weight bearing does not occur, the relatively thin (100 micron or less) tear layer is considered by scholars to be disadvantageous because it creates a thin film adhesion in the enclosed space that increases the absorption between the scleral contact lens and the ocular surface, resulting in difficulty in lens removal, particularly after prolonged lens wear, where tear fluid therein is more viscous due to ocular surface secretions, metabolites, etc. Of course, there is no determination in the art as to how much of the corneal space is ideal, but it is currently believed that at least a 250 micron corneal space should be guaranteed during initial lens prescription.

The inventor finds that in the closed scleral contact lens of the present invention, by setting the scleral contact lens to fit the proper apex clearance not to exceed 200 microns, not only does the problem of difficulty in removing the lens not occur, but also unexpectedly reduces the lens sedimentation degree, and even at the apex clearance as low as 40 microns, corneal load and damage do not occur after the subject wears the lens for a long time. As used herein, the term "initial apex gap" refers to the distance between the peak of the anterior surface of the cornea and the posterior surface of the scleral contact lens as measured by Optical Coherence Tomography (OCT) or fluorescein staining after a subject wears the lens for 20 to 30 minutes. The initial apex gap according to the present invention is also one of the important parameters that the optician uses to determine whether the selected trial is fit when the scleral contact lens of the present invention is being fitted.

Thus, the initial apex gap between the posterior surface of the optical zone of the scleral contact lens according to the present invention and the apex of the eyeball is less than 200 microns, such as less than 200 μm, less than 190 μm, less than 180 μm, less than 170 μm, less than 160 μm, less than 150 μm, less than 140 μm, less than 130 μm, less than 120 μm, less than 110 μm, less than 100 μm, less than 90 μm, less than 80 μm, less than 70 μm. Apex gaps above 200 microns are undesirable because in the unconfined scleral contact lenses of the present invention, too high an apex gap tends to cause air bubbles to follow the movement of the lens and tear fluid into the lens back space from where the landing zone does not conform to the ocular surface during wear.

In a preferred embodiment, the initial apex gap is above 40 microns, such as greater than 40 μm, greater than 50 μm, greater than 60 μm, greater than 70 μm, for example the initial apex gap is 55, 65, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 160, 165, 170, 175, 180, 185, 190, 195 μm or any value therebetween. An apex gap of less than 40 microns is disadvantageous because the irregular shape of the sclera, and the rotation of the eye in different gaze directions, can cause the lens to be in close proximity to the cornea during movement, with the potential for damage.

Since the scleral contact lens according to the present invention has a thin posterior tear gap in a well-adapted condition in which tear is formed with a thin tear thickness, even if the lens mobility is high, the change in tear thickness caused by it is almost negligible, and does not cause visual fluctuation of the subject.

In some embodiments of the present invention, the transition region of the scleral contact lens is configured to be positioned over the corneoscleral limbus of the eyeball when the scleral contact lens is placed on the eyeball. The corneoscleral limbus is the cornea-sclera junction, which contains stem cells critical to the health of the eye. If the scleral contact lens is in contact with the limbus, damage to stem cells therein may occur; also, if the scleral contact lens vault is too high in this region, it may affect the oxygenation of the corneoscleral limbal stem cells. Thus, in some embodiments of the present invention, the scleral contact lens is further configured to provide a corneoscleral limbus gap of between 75-150 microns.

The specular apex and corneoscleral margin can be quantitatively measured by Optical Coherence Tomography (OCT) and can be assessed both statically and dynamically using fluorescein staining.

(III) edge warping

In some embodiments, the tip of the landing zone is provided with an edge warp. As used herein, "edge lift" refers to the tip of the landing zone not contacting the ocular surface, sometimes also referred to as edge lift or edge lift, and "edge lift" refers to the distance from the tip of the landing zone to the bulbar conjunctiva where the chord length of the eyeball is equal to the diameter of the scleral contact lens (fig. 1).

Generally, because of the larger size of the scleral lens, edge warping is not preferred by the subject because it is more likely that the subject will perceive the presence of the lens (foreign body sensation), and the upper edge warping may also exacerbate Giant Papillary Conjunctivitis (GPC). During the fitting process of the scleral mirror, the ideal situation generally accepted in the field is perfect fit of the landing zone to the sclera (bulbar conjunctiva), no edge tilting, no compression, and no conjunctival whitening (blanching).

However, the present invention utilizes the tear exchange promoting effect of the edge warps. The edge warp arranged at the tail end of the landing zone enables the rear-mirror tear exchange effect of the scleral contact lens to be more excellent.

Furthermore, the inventors have found that by setting the radius of curvature r1 at the junction (J2) of the posterior surface of the landing zone and the posterior surface of the transition zone of the scleral contact lens of the present invention and the radius of curvature r2 (fig. 2) of the distal end of the posterior surface of the landing zone, and setting the radius of curvature of the portion of the posterior surface of the landing zone between the above two points to be gradually (continuously or stepwise) increased radially outward, it is possible to individually control the posterior surface profile of the landing zone, construct a gently raised edge warp, and reduce the foreign body sensation of the subject. Where the radius of curvature at the junction J2, r1, is also the landing zone radius of curvature LZR. In some embodiments, the radius of curvature r1 at the junction (J2) of the landing zone rear surface and the transition zone rear surface is between 8.5 mm and 15.0mm, such as 9.0, 10.0, 11.0, 12.0, 13.0, 14.0, 15.0mm or any value therebetween. The curvature radius r2 of the tail end of the rear surface of the landing zone is 8.65-20.0 mm, preferably 10.0-15.0 mm. Changing r1(LZR) can result in changes in the position of the lens landing on the conjunctiva, changing the sagittal height of the lens as a whole and fitting to the anterior surface of the cornea. Part B of figure 2 shows the landing zone change caused by the r1 change.

In some embodiments, the sagittal height S at J2, S representing the perpendicular distance of the connecting point J2 from the lens edge plane, is set according to the radius of curvature r1 at J2; the larger r1, the smaller S, and the higher the edge curl. Wherein S (r1) ═ a + B × r1+ C × r1 ² +D×r1 ³ ) ^-1 And A is selected from-2 to-150, B is selected from 0.5 to 5, C is selected from-0.06 to-0.6, and D is selected from 0.003 to 0.03. For example, A is-10, B is 2.5, C is-0.28, and D is 0.017. By way of example, suitable rise S is selected from 0.6 to 3.2mm, preferably 1.0 to 2.2mm, more preferably 1.2 to 1.7 mm. The inventors have found that varying the landing zone of the scleral contact lens within this range provides an edge warp of a suitable height to establish a balance between tear exchange and subjective perceived comfort of the subject.

(IV) other lens characteristics

In some embodiments, the scleral contact lens of the present disclosure further comprises a through-hole (ligation) and/or pocket (pocket) disposed in the optical zone and/or transition zone of the scleral contact lens (fig. 2). The through holes are small holes drilled in the scleral lens to help improve tear exchange under the lens and/or provide more available oxygen through the lens. The horizontal cross section of the through hole has a maximum dimension selected from 0.2-1.0 mm. The pocket, unlike the through hole, is a non-penetrating structure having an opening on the rear surface of the lens. The pockets suitable for use in the present invention may have a variety of profiles. The pockets may reduce the average thickness of the lens, increasing the oxygen permeability of the lens, and thus, in some embodiments, the scleral contact lens of the present invention is provided with a plurality of pockets on the posterior surface. In some embodiments, the pocket is configured to trap and restrict air bubbles that may enter the retrospecularly gap through the through hole, such as described in CN 112666723A. Which is incorporated herein by reference in its entirety.

In still other embodiments, the scleral contact lens of the present invention has an optical zone diameter φ _a0 Is between 5.00 and 12.00 mm. The central thickness of the optical area is between 0.15 mm and 0.55mm, so that sufficient lens strength is provided and good lens oxygen permeability is considered at the same time. In various embodiments, the posterior surface of the optical zone can be spherical, aspherical, or toric. In various embodiments, the optical zone posterior surface can have a radius of curvature that is greater or less than the corneal radius of curvature. In some embodiments, the radius of curvature r0 of the posterior surface of the optical zone (i.e., the Base Curve Radius (BCR) of the scleral contact lens) is between 5.0mm and 14.0mm, such as between 5.5 mm and 12.0mm, such as 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5 and any value therebetween.

In various embodiments, the width of the transition zone (i.e., + -. phi.) of scleral contact lenses of the invention _a1 Phi and phi _a0 Half of the difference) is between 0.8 and 1.8mm, preferably between 1.0 and 1.5 mm. In various embodiments, the radius of curvature at the junction (J1) of the posterior surface of the transition zone with the posterior surface of the optical zone (i.e., at the beginning of the transition zone) (i.e., transition zone radius of curvature (TZR)) is greater than or equal to the base arc radius of curvature, e.g., 0.1-2.0 mm greater than the base arc radius of curvature, e.g., 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9mm greater and any value therebetween. Thus, in various embodiments of the present invention, the radii of curvature of the optical zone back surface and the transition zone back surface are linked.

In various embodiments, the radius of curvature of the landing zone of the scleral contact lens of the present invention is not dependent on the BCR setting, but rather on the desired tip height, as long as it is greater than the BCR.

In various embodiments, the scleral contact lenses of the present invention have a diameter of 14.0 to 25.0mm, preferably 14.0 to 18.0 mm.

TABLE 1 exemplary scleral contact lenses of the invention

Fitting of two, sclera contact lens

Fitting of scleral contact lenses includes pre-fitting inspection, fitting evaluation, parameter adjustment, and ordering of custom lenses.

The examination before prescription includes medical history collection, eye health examination, eye parameter measurement, subjective and objective optometry, etc. The eye parameter measurement comprises corneal curvature, corneal morphological parameters, corneal diameter, pupil diameter measurement and the like. Knowledge of corneal morphology is the basis for the selection of trial film base curves. Corneal curvature may be measured using a keratometer and corneal topography. The corneal topography can reflect the complete appearance of the cornea more completely, so the corneal topography has wider application in practice.

Based on the results of the pre-fitting examination, the optician will select the first fitting for the subject to be evaluated for fit. Good scleral contact lens fit includes three basic aspects: suitable corneal space, corneoscleral margin space and scleral fit. Therefore, fitting evaluation includes an evaluation check of the optical zone, transition zone and landing zone, for example, using a pen lamp or slit lamp after wearing for 5 minutes to roughly evaluate whether there is corneal contact or air bubbles in the central zone, whether there is a lifting of the landing zone, vascular compression, etc., while asking the subject for comfort. If the first piece is positioned in the middle, and has no contact, large bubbles and obvious discomfort, the first piece is worn for 20 minutes and then is evaluated by adopting slit lamp fluorescein; otherwise, the test piece is replaced and evaluated again. The fitting of conventional scleral contact lenses typically requires a long time to evaluate at 20-30 minutes, 2 hours and 4 hours of lens wear. Criteria for successful scleral contact lens fitting include good dynamic and static assessment (no air bubbles, no contact, including no contact at both the corneal and corneal limbus portions), improved vision correction by on-chip optometry, and good subject comfort.

If the fitting of the fitting piece is not good enough, the optician needs to select the fitting pieces with other parameters for the subject according to the situation until good fitting is obtained, and then the optician can order the corresponding products for the subject according to the parameters of the fitting pieces. Scleral contact lenses designed by different manufacturers typically require the optician to adjust to different lens parameters and provide corresponding fitting guidelines. Some scleral contact lenses have complex design, more adjustable parameters and complex fitting.

The scleral contact lens according to the present invention is simple in design and therefore relatively simple to fit. Accordingly, in some embodiments, the present invention also provides a method of fitting a scleral contact lens. As shown in fig. 5, the method includes measuring a corneal morphology of a subject, for example, using a corneal topography, to obtain a flat K value (FK) and a corneal eccentricity e value corresponding to FK of the subject's cornea (step 110); selecting a first try-on piece of a scleral contact lens for the subject based on the FK value and the e value, the optical zone of the first try-on piece having a first base arc radius of curvature (BCR) ₁ And its landing zone has a first landing zone radius of curvature LZR ₁ (step 120).

Wherein the step of selecting the first try-on piece comprises: calculating a suitable lens rise from the FK, e values and target initial apex gap (40-200 μm) and a base arc radius of curvature from the lens rise and base arc eccentricity (0.30-1.10, preferably 0.5-0.99); and subtracting a correction parameter C within the range of 0.2-0.5 from the calculated base arc curvature radius to obtain the base arc curvature radius of the first try-on piece. The calculation formulas required for the various steps are well known in the art, see for example those described in Contact lens optics and lens design, ISBN 978-0-7506-. In a preferred embodiment, the correction parameter is 0.3.

The method of the invention also comprises a fitting evaluation (step 130) after wearing the lens for 20-30 minutes, for example, the fitting evaluation is carried out by dropping sodium fluorescein, and the evaluation contents comprise: whether the lens is positioned in the middle or not and the mobility; whether the center has large bubbles or not and whether the center has contact or not; the middle periphery (transition zone) of the lens is pressed or not; the periphery (landing area) of the lens is pressed or not. FIG. 3 illustrates several situations in which lens fitting may occur where a flat fit is manifested as a too thin clearance behind the lens or a contact in the center; steep fitting is characterized by large bubbles in the center; the fluorescent layers are perfectly matched with the visible mirror and then are uniformly distributed. In both flat and steep fits, it is necessary to adjust the parameters of the fitting, such as BC radius of curvature or edge warping. In the field of fitting contact lenses, particularly hard lenses (e.g., RGP, orthokeratology, and scleral contact lenses), adjusting the corresponding lens parameters according to the fitting evaluation result of the fitting piece is a conventional technical means in the field. As a simple example, for example, in the method of the invention, if compression of the optical zone is observed, or the apex separation is less than 40 μm, the BC can be steepened (smaller BCR), increasing the lens sagittal height, away from the cornea; if the optical zone has a large bleb or a tip gap greater than 200 μm, and/or the limbal gap is too large or bleb, then the trial is replaced with a larger BCR. If the landing zone is pressed, the edge can be relaxed and tilted, and r1 (namely LZR) is larger; if the landing zone has bubbles, then choose a smaller r1, reduce the edge warp. Fig. 4 shows several situations of poor edge lift fit of the lens.

In some embodiments, the methods of the invention further comprise measuring the apex gap and/or the corneoscleral margin gap, for example by OCT.

Further, the method of the present invention further comprises customizing or ordering a scleral contact lens having the parameters based on the ideal BCR and edge tilt height (characterized by LZR) obtained from the fitting assessment and the diopter strength of the subject (step 140). Those skilled in the art will appreciate that the order parameters may also include other specific specifications, such as adjusting the lens diameter, polishing the lens well, etc. However, in various embodiments, the methods do not include the step of measuring the topography of the scleral surface of the subject, nor do the parameters listed below include parameters associated with the scleral topography.

In still other embodiments, the methods of the present invention further comprise performing multiple corneal topography measurements to ensure data consistency and accuracy.

Because the scleral contact lens of the present invention has dynamic tear exchange with no or only slight sedimentation, there is no need to wait for an evaluation time of up to 4 hours during lens fitting, and an ideal fitting lens can be found by merely adjusting the BC and edge warping of the lens, thereby greatly shortening and simplifying the lens fitting process.

Thus, in accordance with yet another embodiment, the present invention also provides a set of fitting sheets for scleral contact lens fitting that provides different combinations of lenses BCR and LZR for selection by the optician. Specifically, the fitting sheet set includes: the high-side warping subgroup containing a plurality of first test wear pieces and the low-side warping subgroup containing a plurality of second test wear pieces, the curvature radiuses of the landing zones of the first test wear pieces are all LZR1, the curvature radiuses of the landing zones of the second test wear pieces are all LZR2, wherein the LZR1 is larger than the LZR2, and the LZR1 and the LZR2 are respectively and independently selected from 8.5-15.0 mm; and the plurality of first try-on pieces respectively have different base arc curvature radiuses, the plurality of second try-on pieces respectively have different base arc curvature radiuses, the base arc curvature radiuses of the first try-on pieces and the second try-on pieces are all selected from the same base arc curvature radius set, and the base arc curvature radius set comprises a plurality of preset base arc curvature radiuses which are distributed in equal steps (for example, the step is selected from 0.2-1.0 mm, for example, the step is 0.5mm) and selected from 5.0-14.0 mm.

In some embodiments, the number of the first try-on pieces is the same as the number of the second try-on pieces. In still other embodiments, the number of the preset base arc curvature radii is the same as the number of the first try-on pieces and/or the number of the second try-on pieces. In some embodiments, the set of try-on pieces further comprises a material having a composition other than LZR ₁ And LZR ₂ Other subsets of the LZR, which likewise comprise a plurality of test strips. For example, the set of fitting pieces further includes a middle warp subgroup including a plurality of third fitting pieces, each having a landing zone radius of curvature of LZR3 and LZR1>LZR3>LZR2。

By way of example, the present invention provides a scleral contact lens fitting set comprising: (1) a high side warp subgroup with 13.0mm LZR1 comprising 14 first try-ins, (2) a low side warp subgroup with 10.0mm LZR2 comprising 14 second try-ins, and (3) a medium side warp subgroup with 11.5mm LZR3 comprising 14 third try-ins, wherein the set of base arc radii comprises the following 14 predetermined base arc radii of curvature 6.0, 6.2, 6.4, 6.6, 6.8, 7.0, 7.2, 7.4, 7.6, 7.8, 8.0, 8.2, 8.4, 8.6 mm.

Thirdly, indications of the scleral contact lens of the invention

The scleral contact lens according to the present invention is suitable for (1) patients with irregular astigmatism of cornea such as keratoconus, corneal limbal degenerative disease, astigmatism after corneal transplantation, and the like; (2) treatment of ocular surface diseases such as dry eye, corneal neuralgia, GVHD graft-versus-host reactions, severe ocular surface diseases such as persistent epithelial defect non-healing (PED), and combination therapy with drugs such as lubricants, acutely, cyclosporine eye drops, and other ophthalmic procedures such as amniotic membrane transplantation, blepharospinous surgery; (3) non-emmetropic eyes, such as ametropia, presbyopia.

Examples

Example 1

Patient a: 30 years old, male, left eye chemical injury after visual deterioration for 3 years

Basic information of the eye: naked eye vision 0.05, subjective refraction OS-0.75/-2.25 x 150, and best corrected vision 0.4

The patient's corneal plateau was measured by corneal topography as a K value of 8.46 and an e value of 0.94

First try-on piece: BC 8.6mm, medium edge warped (junction rise S ═ 1.47mm), inspected by slit lamp 20 minutes after wearing the mirror: the central corneal post-lens tear layer is thin, about 20 μm thick; the peripheral retrospecularly tear layer is thin, with a thickness of about 40 μm; the paranasal conjunctiva is whitened, the lens is centered well, and the lens mobility is absent in a natural blinking state.

The method is characterized in that the method is adjusted to be high-edge upwarping (the rise S of the connecting part is 1.40mm), a trial wearing piece with the steep BC of 8.2mm is selected, the lacrimal fluid layer filling amount of the central and peripheral corneal lenses is detected to be 100 mu m through a slit lamp after the glasses are worn for 20 minutes, the landing area is well matched, the conjunctiva blood flow is evaluated statically and statically without blocking, the lenses are well centered, and the lenses have small mobility of about 0.5mm in the natural blinking state. The chief complaint was not foreign body sensation.

The examination is carried out after one month of lens wearing, and the lens wearing is mainly used for optometry: -0.75/-0.50 x 180, with 0.8 vision with glasses.

Example 2

Patient B: keratoconus for 22 years old, male and left eye 2 years after keratoconus

Basic information of the eye: naked eye vision 0.15, subjective refraction OS-4.00/-3.75 x 80, and best corrected vision 0.3

The corneal flatness K value of the patient was measured by corneal topography as 8.39, and the e value was measured as 0.21

First try-on piece: BC 7.2mm, medium edge warped (junction rise S ═ 1.47mm), inspected by slit lamp 20 minutes after wearing the mirror: a central corneal contact; air bubbles behind the peripheral lens; the landing area is well matched, conjunctiva blood flow is not blocked in dynamic and static evaluation, the lens is well centered, and the lens has small mobility of about 1.0mm in a natural blinking state.

Adjust to a steeper BC 7.0mm trial, medium edge warp (junction rise S1.47 mm), inspect through slit lamp 20 minutes after wearing the mirror: the central cornea is not contacted, and the thickness of the lacrimal fluid layer after the mirror is 100 mu m; small mobile bubbles behind the perimeter mirror; the landing area is well matched, conjunctiva blood flow is not blocked in dynamic and static evaluation, the lens is well centered, and the lens has micro mobility of about 0.5mm in a natural blinking state. The chief complaint was not foreign body sensation.

After one month of lens wearing, the optometry of the principal angle of the lens wearing is-0.50/-0.50 x 145, and the vision of the lens wearing is 0.8.

Example 3

Patient C: 31 years old, female, high myopia of both eyes 20+ years

Basic information of the eye: naked eye vision 0.01, subjective refraction OD-10.75/-3.25 x 5, and best corrected vision 0.8

The corneal flatness K value of the patient was measured by corneal topography as 8.11, and the e value was measured as 0.78

First try-on piece: BC 8.0mm, medium edge warped (junction rise S ═ 1.47mm), inspected by slit lamp 20 minutes after wearing the mirror: the central corneal post-lens tear layer is thin, with a thickness <20 μm; the peripheral retrospecularly lachrymal layer was full, with a thickness of about 100 μm; the paranasal conjunctiva whitens, the lens is well centered, and the lens mobility under the natural blinking corpus is <0.5 mm.

Adjusting to a BC 7.6mm trial piece with high edge upwarp and steeper, and inspecting through a crack lamp after wearing a mirror for 20 minutes: the central corneal post-mirror tear layer is moderate, about 50 μm; small mobile bubbles behind the perimeter mirror; the landing area is well matched, conjunctiva blood flow is not blocked in dynamic and static evaluation, the lens is well centered, and the lens has micro mobility of about 0.5mm in a natural blinking state. The chief complaint was no foreign body sensation.

After one month of lens wearing, the examination of the chief angle of the lens wearing is-0.25/-0.50X 34, and the vision of the lens wearing is 1.0.

While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the invention is intended to cover all such modifications and changes as fall within the true spirit of the invention.

Claims

1. A method of fitting a scleral contact lens to a subject, the scleral contact lens comprising an optical zone disposed at the center of the lens, a blend zone surrounding the optical zone, the optical zone having a base curve radius of curvature (BCR), the blend zone having a blend zone radius of curvature TZR, and a land zone disposed at the periphery of the lens, the land zone having a land zone radius of curvature LZR, wherein TZR is dependent on BCR but LZR is independent of BCR,

the method comprises the following steps:

measuring corneal morphology of the subject to obtain a Flat K (FK) value and a corneal eccentricity e value corresponding to the FK value of the subject's cornea; and

selecting a first trial of the scleral contact lens for the subject based on the FK value and the e-value, the first trial having an optical zone with a first Base Curve Radius (BCR) ₁ And its landing zone has a first landing zone radius of curvature LZR ₁ 。

2. The method of claim 1, wherein the step of selecting a first fitting includes:

calculating a lens rise from the FK value, the e value, and a target initial vertex gap;

calculating a theoretical base arc curvature radius from the lens rise and base arc eccentricity; and

obtaining the first base arc curvature radius BCR by subtracting a correction parameter C from the calculated theoretical base arc curvature radius ₁ ，

Wherein the target initial vertex gap is selected from 40 to 200 μm, the base arc eccentricity is selected from 0.30 to 1.10, and the correction parameter C is selected from 0.2 to 0.5.

3. The method of claim 1 or 2, wherein the BCR is selected from 5.0-14.0 mm; and/or

The TZR is 0.0-2.0 mm larger than the BCR; and/or

The LZR is greater than the BCR and is independently selected from 8.5-15.0 mm.

4. The method according to any of the preceding claims, wherein the method further comprises:

after the subject wears the first fitting piece for 20-30 minutes, carrying out fitting evaluation on the first fitting piece, wherein

Customizing the BCR for the subject if the first fitting is well-fitted ₁ And LZR ₁ The scleral contact lens of (a);

selecting a BCR with a second base arc radius of curvature for the subject if the first fitting is not well-fitted ₂ And/or secondary landing zone radius of curvature LZR ₂ And performing fitting evaluation again 20-30 minutes after the subject wears the second fitting sheet, wherein BCR ₂ Is different from BCR ₁ ，LZR ₂ Other than LZR ₁ 。

5. The method of claim 4, wherein the fitting evaluation comprises: the apex gap and/or the corneoscleral edge gap are measured.

6. The method of any preceding claim, wherein measuring the corneal morphology of the subject is by corneal topography measurement, and preferably the method comprises performing a plurality of corneal topography measurements.

7. A set of trial lenses for fitting a scleral contact lens, the trial lens being a scleral contact lens and comprising an optical zone disposed at the center of the lens, a blend zone surrounding the optical zone, the optical zone having a base curve radius of curvature BCR, the blend zone having a blend zone radius of curvature TZR, and a land zone disposed at the periphery of the lens, the land zone having a land zone radius of curvature LZR, wherein TZR is BCR dependent but LZR is independent of BCR,

the fitting patch group includes: the high-edge warping subgroup containing a plurality of first test wearing pieces and the low-edge warping subgroup containing a plurality of second test wearing pieces, wherein the curvature radiuses of the landing areas of the first test wearing pieces are the first curvature radiuses LZR of the landing areas ₁ And the curvature radiuses of the landing areas of the plurality of second try-on pieces are all the second curvature radiuses LZR of the landing areas ₂ Wherein LZR ₁ Greater than LZR ₂ And LZR ₁ And LZR ₂ Each independently selected from 8.5-15.0 mm; and

the first try-on pieces are provided with different base arc curvature radiuses, the second try-on pieces are provided with different base arc curvature radiuses, the base arc curvature radiuses of the first try-on pieces and the second try-on pieces are all selected from the same base arc curvature radius set, and the base arc curvature radius set comprises a plurality of preset base arc curvature radiuses which are distributed in an equal step mode and are selected from 5.0-14.0 mm.

8. The set of try-on sheets according to claim 7, wherein the number of the first try-on sheets and the number of the second try-on sheets are the same.

9. The set of try-on sheets according to claim 7 or 8, wherein the number of the preset base arc curvature radii is the same as the number of the first try-on sheets and/or the number of the second try-on sheets.

10. The set of try-on pads according to any of claims 7 to 10, further comprising a material with a composition different from LZR ₁ And LZR ₂ Other subgroups of LZR.