HK1088666B - Contact lenses with blended microchannels - Google Patents

Description

Contact lens with micro-grooves

Technical Field

The present invention relates generally to contact lenses. And more particularly to contact lenses having microchannels that are effective in promoting tear fluid exchange.

Background

It has long been recognized that prolonged contact lens wear can cause corneal complications. The deleterious effects of extended wear of eyeglasses are believed to be caused primarily by the accumulation of debris trapped at the lens-eye interface.

The cornea is a living tissue and has an effective metabolic action. Waste products such as lactic acid, carbon dioxide and water produced by this metabolism must be drained from the cornea. Contact lens wear causes debris to be trapped at the lens-eye interface, which often originates, for example, from such waste products expelled from the eye, dead epithelial cells, and other materials. Such debris, if left to accumulate in the eye, may damage the eye, for example, causing irritation and/or other damage to the eye, and/or damage to the overall eye health of the lens wearer. In order to maintain eye health, the cornea must receive an appropriate amount of oxygen because the cornea does not receive oxygen from blood as does other living tissue. If insufficient oxygen reaches the cornea, swelling of the cornea may occur.

To address the problem of oxygen deprivation due to extended wear of contact lenses, hydrophilic lenses have been proposed that have high permeability characteristics to oxygen. Hydrophilic lenses, sometimes referred to as hydrogel lenses, are soft, flexible, water-containing lenses. Clinical studies of hydrophilic lenses have indeed demonstrated a considerable reduction in corneal swelling, even if worn permanently, in persons who wear such lenses.

Unfortunately, however, the use of conventional hydrophilic lenses does not eliminate all the deleterious effects on the cornea that result from contact lens wear, particularly permanent lens wear. For example, conventional hydrophilic lenses do not address the problem of accumulation of debris at the lens-eye interface. This has suggested that other problems need to be addressed in developing safe, permanently worn soft contact lenses.

One important issue is the effective tear film exchange between the exposed surface of the eye and the ocular surface covered by the lens. The tears ensure hydration of the sensitive tissues of the eye and continuous flushing of debris out of the eye. Tear film exchange between the eye and the posterior, eye-facing end of the contact lens is considered to be an important factor in maintaining ocular health. Tear film exchange can remove dead epithelial cells, foreign particulate matter, and other debris that would otherwise be trapped between the lens and the eye. It has been hypothesized that increasing tear film exchange not only improves corneal health, but also limits concomitant diseases such as ocular infections, e.g., microbially-induced keratitis.

Rotating the eyeglasses on the eyes has long been recognized as a method of maintaining eye health and comfort. For example, U.S. patent No.2989894 to Gordon discloses a contact lens having five evenly spaced spiral-shaped inclined channels formed on the inner surface of the lens. The channels are illustrated and shown as extending toward the center of the lens, but not as far as the cornea. The slow constant rotation of the lens is said to prevent the lens from over fitting the cornea. The helical inclination of the channel is said to enable the lens to rotate in both clockwise and counterclockwise directions depending on the direction of the helical inclination of the channel.

More recently, Hofer et al, U.S. Pat. No.5166710, discloses a contact lens having a corneal region that is spaced apart from the corneal surface when the lens is worn on the eye. The structure is formed so that the spectacles rotate when the wearer blinks his or her eyes. According to Hofer et al, tear film is transported along the surface of the eye by creating an "eddy current effect" in the applanation region of the lens which, in response to blinking, causes rotation of the lens on the eye. The patent also teaches that tear transport can be formed by a groove on the rear surface of the lens body. Hofer et al show and describe that the recess may be a concave portion in the posterior surface of the lens body, which may be fluted or serrated in shape. Hofer et al states that "thin corrugated curved flutes" may also be formed.

Nicolson et al, U.S. patent No.5849811, discloses the development of a lens material that balances the permeability of oxygen with the permeability of ions or water sufficient to cause the contact lens to "move on the eye", i.e., the movement of the lens over the surface of the eye.

The entire contents of each of the above patents are incorporated herein by specific reference.

Despite the great advances made in developing comfortable, safe, permanent contact lenses, there remains a need for improved contact lenses, such as lenses that are effective in tear exchange in the surface region of the eye, particularly in the corneal region.

Disclosure of Invention

Novel contact lenses have been discovered that are effective in facilitating tear film exchange between the exposed surface of the eye and the surface of the eye covered by the contact lens. This exchange of tears or tear film outside the edge of the lens with tears or tear film located behind the lens, i.e., between the lens and the eye or at the lens-eye interface, enhances removal of debris from the lens-eye interface. The tear film located between the cornea and the contact lens is sometimes referred to herein as the posterior lens tear film (PoLTF). Constant rinsing of PoLTF can enhance ocular health and/or can result in extended wear of contact lenses and reduced deleterious effects on the cornea.

The contact lenses of the invention, such as permanent wear contact lenses, can remove debris from beneath the contact lens by continuously rinsing the PoLTF to enhance tear mixing; it is desirable to enhance the rate of oxygen delivery to the cornea; or preferably does not rely on lens rotation to promote effective tear fluid or tear film exchange.

In one broad aspect of the invention, a contact lens is provided that generally includes a lens body having a posterior surface and an anterior surface. The lens body can be configured to reduce the time required to exchange 95% of tear fluid, e.g., PoLTF, when the lens is worn on the eye, by, e.g., at least about 5% or at least about 15% relative to a substantially identical contact lens that does not include or include a plurality of microchannels. In another aspect of the invention, it is preferred that the lens body comprising a plurality of microchannels as described herein be configured to flex the lens body toward an eye fitted with the contact lens in response to forces exerted by the eyelid on the lens, thereby at least assisting in the effective tear fluid exchange between the exposed ocular surface and the surface of the eye covered by the lens body, and reducing the time required to achieve a tear fluid exchange rate of 95% by at least about 15% when the lens is fitted to the eye, as compared to a substantially identical contact lens that does not flex as much.

Without wishing to limit the invention to a particular theory of action, it is believed that this configuration of the lens body, for example in response to a blinking action of the eyelid, will cause the lens to produce a significantly effective tear pumping or rinsing action between the lens and the ocular surface covered by the lens. Specifically, in accordance with this aspect of the invention, when the eyelid is closed, such as during a blinking motion, the eyelid will push the lens closer to the cornea, thus forcing some of the PoLTF out of the underside of the lens. When the eyelid is subsequently raised, the elasticity of the lens causes the lens to rebound and move away from the cornea, thereby drawing tears from the tear film onto the surrounding sclera and effectively replenishing the PoLTF.

In certain embodiments of the invention, the thickness of the lens body is preferably continuously variable along a radius (radius) extending from the optical axis of the lens body circumferentially across at least a portion of each of the microchannels.

For example, the plurality of microchannels may form a plurality of undulations along the outer circumferential surface. In particular, the plurality of microchannels form a substantially continuous, preferably substantially jointless, corrugated shape. In other words, the plurality of microchannels preferably define substantially continuous curved surfaces that generally extend from the lens of the lens across the peripheral portion of the lens body.

Each of the microchannels preferably has a width in the range of about 5 deg. to about 30 deg. (e.g., forming a substantially circular array along 360 deg.). The plurality of microchannels includes about 3 to about 200 microchannels, and preferably includes about 10 to about 100 microchannels.

In one embodiment of the invention, the lens includes an optical zone substantially free of the plurality of microchannels. For example, a plurality of microchannels may be formed only in the peripheral portion of the lens.

Each of the microchannels preferably includes a curved surface that is not convex with respect to the anterior surface of the lens body. Each of the microchannels is preferably substantially continuously curved in both radial and annular directions, wherein "in the annular direction" is defined as along at least one radius extending from the optical axis of the lens body.

In certain useful embodiments of the present invention, at least two of the microchannels define a wave pattern in a circumferential direction. In accordance with the use of the present invention, the waveform is a continuous curve including the apex of each of the at least two microchannels. In this regard, the apex of the micro-groove is the rearmost point of the micro-groove. The plurality of microchannels preferably form a substantially continuous wave pattern in the annular direction, and more preferably form a wave pattern having substantially no junction in the annular direction, the wave pattern having grooves in the thinnest region of the lens body and peaks in the thickest region of the lens body. In aspects of the invention, the waveform is periodically repeated around at least a portion of the periphery of the lens.

In another broad aspect of the invention, a contact lens is provided, the lens comprising a lens body having a posterior surface and an anterior surface, the lens body comprising a plurality of microchannels, each microchannel comprising a curved surface that is generally non-concave, and preferably generally convex, relative to the anterior surface of the lens body. The curved surface of each micro-groove is located in the rear side region of the micro-groove.

In one embodiment, the thickness of the lens body varies substantially continuously along a radius extending from the optical axis of the lens body across at least a portion, e.g., a major portion or substantially all, of each of the microchannels in the transverse direction. In one embodiment, the thickness of the lens body varies substantially continuously along a radius extending from the optical axis circumferentially across only a portion of each of the grooves.

Each of the microchannels is preferably substantially smooth or continuously curved in both radial and circumferential directions without a land.

Each of the microchannels preferably has a tapered shape extending toward the optical axis of the lens body in at least one of the width and depth of the microchannel.

In one embodiment of the invention, the lens includes an optical zone that is substantially free of the plurality of microchannels. For example, the plurality of microchannels may be formed only in the peripheral portion of the lens.

In addition, without intending to limit the invention to any theory of applicability, it is believed that the generally non-concave curved surfaces of the microchannels are effective in enhancing tear fluid exchange, for example, by at least about 15%, and preferably by at least about 35% or more, as described herein, as compared to identical contact lenses without microchannels or including microchannels without such curved surfaces.

When the above-mentioned T is adopted₉₅When tested, the present contact lenses may be configured to reduce the time to 95% tear fluid exchange rate by at least about 15%, or at least about 20%, or at least about 25%, or at least about 30%, or at least about 35%, or more, when the lens is worn on the eye, as compared to a control contact lens, e.g., a substantially identical contact lens without microchannels or without the present microchannels.

In another broad aspect of the invention, a contact lens is provided that generally includes a lens body and a plurality of microchannels formed in a posterior surface of the lens body, each microchannel being in substantially abutting relationship with one or more microchannels. The microchannels are sized to facilitate, or preferably increase, tear fluid exchange rate between the exposed surface of the eye and the surface of the eye covered by the lens.

The microchannels, such as each of the adjacent microchannels, are preferably sized and/or shaped to provide a significant interstitial spacing between the posterior surface of the lens body and the ocular surface, for example, when the lens is worn on the eye. For example, a plurality of microchannels may occupy a substantial portion of the posterior surface, thereby allowing a uniform PoLTF to be formed between the ocular surface and the lens. For example, in accordance with the present invention, the plurality of microchannels may occupy at least about 15%, or about 20% -30%, or about 50% or more of the portion of the backside surface on which the microchannels are disposed. The contact lens is preferably structured to flex or separate the lens body toward the eye in which the contact lens is worn in response to eyelid movement, upon contact or separation, respectively, with the lens body, thereby at least facilitating effective tear fluid exchange between the exposed surface of the eye and the surface of the eye covered by the lens body.

Each adjoining microchannel includes a curved surface that is generally not concave relative to the anterior surface of the lens body. For example, each of the microchannels includes a curved surface that is generally convex with respect to the anterior surface of the lens body.

The lenses of the invention are preferably produced by machine cutting. In particular, it is preferred that a plurality of microchannels be machined into the tooling inserts used to form the contact lens molds.

Alternatively, the microchannels of the contact lenses of the invention may be formed by any suitable technique or process, or combination thereof. Such microchannels are preferably formed during the manufacture of contact lenses by techniques that are conventional and well known in the art. For example, there are at least three possible methods in the manufacturing process of contact lenses for forming microchannels. These methods are as follows:

(preferred) the molded insert is etched or machined by methods such as chemical methods, laser methods, EDM methods, photolithography methods, UV irradiation methods, micromachining methods, etc.;

forming a mold surface on a thermoplastic mold by some method, such as microcontact printing;

the microchannels are formed directly in the lens, for example, with a laser or the like.

It should be appreciated that the tear film on the lens/eye surface may be continuously flushed with tear fluid from other portions of the eye outside the lens edge after the lens of the present invention has been worn for an extended period of time. This flushing of the tear film, which typically contains a significant amount of debris, away from the lens-eye interface with the "clean" tear film will reduce the concentration of debris, thereby allowing the lens to be worn for a longer period of time before the lens is removed from the eye. This continuous tear film cleaning, even if the lens is not worn for a prolonged period of time, produces a significant beneficial effect on the eye health of the wearer of the lens.

The enhanced removal of debris by the present invention is particularly useful when used in conjunction with contact lenses having high oxygen permeability, for example, hydrophilic contact lenses such as contact lenses made of hydrophilic polymeric materials, contact lenses made of silicone hydrogel materials, and the like.

Each of the above-described features, as well as various combinations of two or more of such features, are all included within the scope of the present invention provided that the features included in such combinations are mutually inconsistent.

These and other aspects of the present invention will be apparent from the following detailed description, examples and claims, particularly when read in conjunction with the accompanying drawings wherein like parts are designated with like numerals.

Drawings

FIG. 1 is a perspective view of a contact lens of the present invention comprising a plurality of microchannels formed in a posterior surface of the lens;

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a schematic view illustrating a microchannel structure of the eyewear shown in FIG. 1;

FIG. 4 is a plan view showing the posterior surface of the contact lens shown in FIG. 1;

FIG. 5 is a plan view of the posterior surface of a contact lens according to another embodiment of the invention;

FIG. 6 is a perspective view of another contact lens of the present invention;

FIG. 7 is a cross-sectional view taken generally along line 7-7 of FIG. 6;

FIG. 8 is a schematic view illustrating the microchannel structure of the lens of FIG. 6;

fig. 8A is a schematic view showing another microchannel structure of a contact lens of the invention.

Detailed Description

Referring now to fig. 1 and 2, a contact lens 10 of the present invention is shown. The contact lens 10 has a lens body 14 with a posterior side 16 and an opposite anterior side 17 (not visible in fig. 1). The posterior surface 16 includes an optic zone 18 configured to correct vision and a peripheral portion 22 and an outer edge surface 24 generally surrounding the optic zone. As used herein, the posterior surface 16 is the surface of the lens 10 that faces the eye when the lens is worn.

The eyeglass 10 of the present invention generally comprises a plurality of microchannels 30 formed in the posterior surface 16. Generally speaking, the lens body 14 is configured such that the lens body 14 flexes in a direction generally indicated by arrow 28 toward an eye in which the contact lens 10 is worn in response to forces exerted by the eyelid on the lens body 14, thereby at least contributing to an effective increase in tear fluid exchange rate, such as by stably renewing PoLTF as described elsewhere herein.

The microchannels 30 are preferably sized and adapted to effectively enhance tear fluid exchange between the exposed ocular surface and the ocular surface covered by the lens body 14.

The lenses of the invention are preferably configured to provide improved tear mixing, when the lens is worn on the eye, of at least about 15%, alternatively at least about 20%, alternatively at least about 25%, alternatively at least about 30%, alternatively at least about 35% and more, relative to an identical contact lens that does not include microchannels or does not include microchannels as described and illustrated herein. For example, the present contact lenses preferably include a lens body configured to reduce the time required to achieve a 95% tear fluid exchange rate by at least about 15%, or at least about 20%, or at least about 25%, or at least about 30%, or at least about 35% and more when the contact lens is worn on an eye (e.g., a human eye) as compared to a substantially identical contact lens without grooves or grooves formed in accordance with the present invention. As described herein, the lenses of the invention can increase tear exchange rates in the range of about 0.4% to at least 46%.

Each of the microchannels 30 preferably includes a curved surface 34 that is generally not concave relative to the anterior surface 17. Specifically, the curved surface 34 is generally convex with respect to the anterior surface 17 and is disposed in a posterior region of the microchannel 30.

This can be seen more clearly with reference to figure 3. Fig. 3 is a cross-sectional view showing the portion of the lens 10 at a particular radial distance from the optical axis of the lens body. For example, FIG. 3 illustrates the thickness of the lens 10 over a radius, or at a distance of about 4mm from the optical axis of the lens body 14. Each micro-groove, e.g., 30', is formed between apex 31a and apex 31 b.

As best shown in fig. 1, the curved surface 34 of each microchannel 30 is substantially continuously curved in a circular direction. The lens body 14 can thus be said to have a thickness that varies substantially continuously along a radius extending from the optical axis of the lens body 14 across adjacent microchannels, such as microchannels 30' and 30 in figure 3, with the thickest portions at the apexes 31a and 31b, it being noted that each apex 31a and 31b is the apex of two microchannels. For example, apex 31b is common to both microchannels 30' and 30.

Each of the microchannels preferably substantially abuts one or more adjacent microchannels. For example, the curved surface of a particular microchannel is configured to substantially meet the curved surface of one or more other microchannels. The plurality of microchannels 30 preferably form a continuous, junctionless curved surface on at least a portion of the posterior surface 16 of the lens 10. The lenses of the invention, such as those having at least partially unbonded microchannels, may provide a wearer comfort advantage over contact lenses incorporating microchannels, such as spaced microchannels having bonded portions or discontinuities (discontinuous edges or sharp edges).

The plurality of microchannels 30 are preferably undulating in a circular direction. In this description, the waveform is defined as a continuous curve that includes the vertices of at least two microchannels. Preferably, the waveform is a substantially continuous waveform. It is further preferred that the plurality of microchannels form a wave pattern substantially free of bonding portions. For example, each of the microchannels is preferably substantially free of bonded portions along at least a portion of the microchannel, preferably along a substantial portion of the microchannel, or along the length of the microchannel.

For example, in the embodiment shown in fig. 1, the plurality of microchannels form a continuous wave pattern extending from the optical zone 18 and across at least a portion of the peripheral portion 22 of the lens body 14. The microchannels 30 are preferably substantially smooth and continuously curved in both the radial and annular directions. The waveform formed by the plurality of trenches is periodic, such as shown in fig. 1. In other words, the microchannels are substantially equidistant from apex to apex, although they need not be.

The thickest portion of the lens body 14 in the region of each microchannel 30 may be up to about 5%, or about 10% to 30%, or about 50%, or about 80% of the maximum thickness of the lens body 14. Each of the microchannels 30 preferably has a taper towards the optical axis across the width from the lens peripheral edge 24 to the optical zone 18. As can be seen from the different perspective views, each of the microchannels preferably has a maximum width at, for example, the peripheral edge of the lens.

The contact lens 10 is configured to enhance tear fluid exchange between the exposed surface of the eye and the lens-covered surface of the eye. The microchannels 30 are effective to enhance or facilitate this tear fluid exchange, preferably by forming a substantially free-flowing tear film at the lens-eye interface. Additionally, the eyewear is configured to be able to rinse at least some of the PoLTF upon each blink.

The plurality of microchannels 30 includes microchannels having a depth that depends on the thickness of the lens itself. For example, the depth of each of the microchannels may be in the range of about 0.1% to about 90% of the thickness of a particular lens body. In one embodiment, each of the microchannels has a depth in a range of about 10% -80% of a thickness of the lens body. For typical contact lens thicknesses, the depth of the microchannels of the invention is between about 0.1 and 50 microns.

In the embodiment shown in fig. 1, the plurality of microchannels 30 extend only to the peripheral portion 16 of the lens 10 and no microchannels 30 are present in the optical zone 18. There may be a bond or discontinuity at the interface between the optical region and each of the microchannels. Preferably, each of the microchannels is completely free of bonding portions other than the bonding portion. A plurality of microchannels 30 extend through at least a portion of the posterior surface 16 from at least the optic zone 18 to the lens rim, and preferably to the rim 24. The absence of microchannels in the optical zone may reduce, or even substantially eliminate, any deleterious effect of the microchannels 30 on the quality of vision or the function of the optical zone formed by the contact lens 10.

To achieve effective tear exchange over an optical zone where microchannels are not present, the contact lens 10 is configured such that the optical zone 18 of the lens 10 is disposed slightly anteriorly relative to the surrounding peripheral portion 22, and particularly relative to the portion or surface of the peripheral edge 22 between the microchannels 30.

Although not specifically shown, instead of microchannels having relatively constant depths, each microchannel 30 may be tapered (tapered) from peripheral edge 24 to optical zone 18. In addition, the optical zone 18 is disposed forward, the distance to the forward side being substantially equal to the depth of the shallowest portion of the micro-groove 30. For example, the optical zone may be configured about 20 microns, or about 10 microns, or about 5 microns or less forward relative to the peripheral portion 22.

Fig. 4 is a plan view showing the posterior surface of the contact lens 10 shown in fig. 1. In this figure, each solid radially extending line (e.g., line 50) represents a notional line over which the curvature of the posterior surface 16 varies from a convex curve to a non-convex curve. In other words, line 50 represents a line of inflection where the posterior surface of the lens changes from a concave surface to a convex surface. One micro-trench 30 is defined to span a region a formed between, for example, the dashed line 50a and the dashed line 50 b. In this particular embodiment 10, the plurality of microchannels 30 includes 12 microchannels, wherein each microchannel occupies an area spanning about 30 ° of the width of the lens.

The plurality of microchannels preferably includes 3-192 microchannels or about 200 microchannels, for example the plurality of microchannels includes about 5 microchannels or about 10 microchannels to about 100 microchannels. For example, fig. 5 shows a similar contact lens 110 of the present invention wherein the plurality of microchannels comprise 24 microchannels, each microchannel occupying about 15 ° of the lens 110. Unless otherwise stated, the lens 110 of fig. 5 is similar in structure and function to the contact lens 10 shown in fig. 1.

Referring now to fig. 6 and 7, another embodiment 210 is shown. The contact lens is similar in construction and function to the contact lens 10, except as specifically described. Parts of the spectacles 210 corresponding to parts of the spectacles 10 are indicated with the same reference numerals, increased by 200.

One of the primary differences between the contact lens 210 and the contact lens 10 is the configuration of the microchannels 230. Specifically, the microchannels 230 each include a posterior portion that forms a convexly curved surface 234 and a portion 240 that is not formed by a curved surface. This can be seen more clearly with reference to fig. 8, which is similar to fig. 3 and shows a schematic view of the spectacles 210. As shown, each micro-groove 230 is formed between vertices, such as vertices 230a and 230 b. The lens 210 thus has a varying thickness at a particular radial distance from the lens' optical center or central optical axis. However, in addition to curved surface 234, each of microchannels 230 includes a relatively flat region 240. As shown, the flat area 240 is located in a thinner region of the lens body 214, while the curved area is located in a thicker region of the lens body 214.

Fig. 8A shows another contact lens 310 of the present invention that is similar to lens 210, except that, except as specifically noted, the contact lens 310 is similar in structure and function to the contact lens 210. Parts of the eyewear 310 that correspond to parts of the eyewear 10 are designated with the same reference numerals, increased by 300.

The primary distinction between the eyewear 310 and the eyewear 210 is that each flat region has a relatively large surface area. This means that the contact lenses of the invention have microchannels with widely varying sizes, shapes and configurations, but still remain within the scope of the invention.

In another aspect of the invention, a contact lens is provided that includes a lens body configured to promote tear mixing for one or more specific individuals, such as individuals having particular ocular and/or eyelid anatomical physiological characteristics. The contact lenses of the invention preferably include lens bodies configured to enhance tear mixing in high eyelid tension persons relative to other persons having low or low eyelid tension. In one embodiment, the contact lens is configured to enhance tear mixing in an asian person as compared to a non-asian person. In general, it is believed that asians, i.e., people of asian lineages or ancestry, such as chinese, japanese, korean, etc., have high eye-to-face tensions relative to non-asian people, which are non-asian lineages or ancestry. While this is generally believed to be true, it should be noted that not all asians have high eye-face tensions compared to all non-asians. A representative population of about 10-15 Asians has a higher average eyelid tension than a representative population of about 10-15 non-Asians.

In another embodiment, contact lenses are provided that include lens bodies configured to enhance tear mixing in persons who do not typically have high eyelid tension. These lenses preferably have lens bodies that include a plurality of microchannels as disclosed herein, except that the microchannels have a lower density, i.e., the lenses have fewer microchannels than contact lenses made for high eyelid tension persons.

In another embodiment, the present contact lenses include lens bodies configured to enhance tear mixing for persons having eye sizes involving relatively thick PoLTF, such as asian persons. In another embodiment, the present contact lenses include lens bodies configured to improve tear mixing for persons having other anatomical characteristics, including, but not limited to, eyelid characteristics that affect the ability of the eyelid to exert forces on the eyeball during blinking, eyelid plate characteristics (e.g., eyelid plate size and/or thickness), eyelid thickness, the presence or absence of wrinkles on the eyelid, the size of the eye opening, the profile of the anterior ocular surface (e.g., corneal profile, limbal profile, and the profile of the limbus and sclera), the position of the eyeball relative to the eyelid, and the degree of eyeball prominence (e.g., the ability of the eyeball to move posteriorly during blinking).

Such contact lenses may be manufactured by the methods disclosed herein to suit a particular population, and may include one or more additional steps of the process of designing contact lenses to enhance tear mixing for a desired population, such as a population having certain ocular and/or eyelid characteristics, including eye shape, musculature, eyelid tension, and the like. Accordingly, contact lenses and methods of making such contact lenses that enhance tear mixing for a particular population or for a specific population or for the population are within the scope of the invention disclosed herein.

The eyewear of the present invention is preferably made by a computer-controlled machine tool cutting process. Or the contact lens may be manufactured using any suitable conventional manufacturing method or combination of methods. Many such methods or processes are conventional and/or well known in the art. These processes include, for example, lathe cutting, laser machining, swaging, injection molding, die casting (half mold, full mold), and the like, and combinations of these processes.

The contact lenses 10, 110, 210, 310 of the present invention are preferably soft lenses made of flexible or hydrophilic silicone or other hydrophilic materials such as suitable hydrogel-forming polymeric materials and the like. With appropriate modification, however, the contact lenses of the invention may be "hard" or "rigid" lenses. The contact lenses of the invention are particularly well suited for extended wear, for example, the lenses may be worn for about 1 day to about 14 days or more without removal, or the lenses may be configured as single use lenses. Materials suitable for the lenses of the invention include, without limitation, conventional hydrogel materials such as hydroxyethyl methacrylate materials, silicone hydrogel materials, gas permeable materials, other lens materials described in U.S. patent No.5849811 to Nicolson et al, other lens materials that are ophthalmically compatible as are well known to the skilled artisan, and the like, and combinations of these materials.

The contact lenses 10, 110, 210 and 310 of the invention can be produced by cutting microchannels into a profiled insert which is then used to form a mold for a contact lens article. Hardware, such as a multiform attachment on an Optiform lathe, i.e., a fast tool servo, may be used to form the profiled insert with the desired geometry. For example, the tool servo mechanism can be programmed to cut profiled inserts over 24 semi-meridians (equally spaced, 15 ° apart) to produce the spectacles shown in figure 1. The tool servo can be programmed to trace the surface to be cut point by point using known techniques, for example using Minifiles, which are conventional and well known to the skilled person. The tool servo mechanism may be additionally programmed so that either or both of the depth and width of the microchannels may be varied. It should be noted that the depth of the micro-grooves need not be constant along their length, i.e. the channels may be made deeper and then shallower from the lens to the peripheral edge. The depth, width and/or configuration of the trenches may vary from one trench to another. The depth of the microchannels at the edge of the lens must of course not be deeper than the thickness of the lens edge.

The hardware for cutting the profiled insert can be modified appropriately to cut about 384 meridians for greater flexibility in the lens process.

The following non-limiting examples illustrate the degree or relative degree of tear mixing that occurs when the lenses of the invention are worn on the eye, and compared to conventional lenses without microchannels.

Examples of the present invention

Tear mixing under a soft contact lens can be estimated by measuring the time required for a tracer substance (e.g., dye, microspheres, red blood cells, etc.) to escape from under the contact lens. Most tear mixture estimates are measured using a fluorometer that measures the change in fluorescence under the contact lens over a specified wearing period. In fluorescence measurements, high molecular weight sodium fluorescein (b) is generally usedMW 600Da) or a dye formulated as a fluorescein/dextrin mixture (PITC-dextrin, manufactured by Smith Chemical, MW 1-12 kDa).Absorbed by the lens with a water concentration greater than about 50%. Therefore, FITC-dextrin (MW 9-12kDa) is preferred to avoid low tear exchange values due to absorption of the tracer dye by the eye or the eye.

Two fluorescence methods are now used to determine tear mixing. One method employs a modified slit lamp that focuses light on the PoLTF while detecting changes in Fluorescence Intensity (FI). The advantage of this approach is to direct the excitation light onto the target area (e.g., tear film). Another fluorescence method employs a scanning fluorometer (Ocumetrics, Inc, Mountain View, CA) that uses a computer-driven stepper motor to deliver laser light from the pre-lens tear film (PrLTF) to the cornea. The fluorometer reads a series of fluorescence intensity readings and provides fluorescence intensity data centered around the FITC-dextrin peak fluorescence below the glasses. Such a fluorometer is sensitive to low concentrations of fluorescent dye. Unfortunately, however, because the location of the light cannot be accurately controlled, measuring the tear mixing rate assumes that no fluorescence is produced on the anterior lens surface. This assumption is considered effective for lenses with slow tear mixing speeds, but is not accurate for lenses with high tear mixing efficiency. These fluorometers are conventional and the details of the various fluorometers will be generally apparent to the skilled artisan.

The method for measuring the tear mixing speed is as follows: baseline autofluorescence readings were obtained with glasses worn on each subject (B)₀Cornea plus eye lens to obtain fluorescence readings). The lens is then removed, a small amount of FITC-dextrin (e.g., 1 microliter) is placed on the posterior surface of the lens and the lens is reinserted onto the cornea, and the fluorescence detected as intensity, for 30 minutes. Subjects were allowed to blink at normal speed or were paced with a metronome requesting blinking at a rate of 15 blinks/minute (mean blink rate). The fluorescence intensity values obtained within the 30 minute observation period were fitted according to an exponential decay pattern, and the dye disappearance rate was determined. After about 30 minutes, there was no substantial change in FITC-dextrin fluorescence intensity, or no detectable change at all.

The exponential decay rate is expressed as a time constant T, defined as the time T required to consume 37% of the dye from under the lens per unit time T. For the calculations, the first 5 minutes of data were discarded, as habitual tearing may occur when the lens was initially inserted. The efficiency of tear mixing is expressed as the time required for the dye to reduce by 95% under the lens, or 3T, where 3T is expressed as T₉₅. Preferably, T is actually calculated directly from fluorescence intensity decay data₉₅Without the need for additional data processing. The above tests were carried out in the kennph Polse laboratory at the university of california (Berkeley).

UnderThe measured T values are shown in tables 1 and 2₉₅Data measured from 26 patients at the time of the trial, who first worn a grooved lens of the invention, specifically a lens fitted with microchannels, having 12 microchannels, with a peak to peak angle of 30 °, similar to the lens 10 shown in figures 1-3, and then worn a substantially identical lens without grooves.

TABLE 1

TABLE 2

Table 1 shows data obtained from 13 asian patients, while table 2 shows data obtained from 13 non-asian patients.

When these data are combined, the mean value T of the grooved contact lens₉₅Is 27.26 minutes, without the mean T of the grooved contact lens₉₅Was 31.66 minutes. Grooved lenses significantly increase tear exchange rate or reduce tear exchange time (p)<0.05). In other words, the tear exchange time is changed by about 14% overall, or the tear exchange rate is increased by about 14% overall.

Mean T of grooved contact lenses when examining data values obtained from 17 patients (of 26 patients) showing decreased tear exchange time or increased tear exchange rate₉₅Is 25.23 minutes, without the mean T of the grooved contact lens₉₅Is 34.86 minutes, which results in an overall reduction in tear exchange time of about 28%. Tear exchange rateThe degree is increased by at least 0.4%, more typically by at least 6%. An increase in tear exchange rate of at least 45% was also observed.

When the data obtained from patients showing reduced tear exchange time were divided into asian and non-asian patients, it is evident that there was an additional difference in tear exchange rates between asian and non-asian patients. For example, for Asian patients, mean T of sulciform contact lenses₉₅Is 23.50 minutes, and for Asian patients, the mean T of the contact lenses without grooves₉₅Is 34.60 minutes, which makes a difference of about 11.10 minutes, or a change in tear exchange time of about 26%. In contrast, for non-Asian patients, the mean T of the grooved contact lenses₉₅28.41 minutes, and for non-Asian patients, the mean T of the non-grooved contact lenses₉₅Is 35.34 minutes, reaches a difference of about 6.94 minutes, or the tear exchange time changes by about 20%.

In addition, these data show that the contact lenses used in this example can enhance tear mixing to a higher percentage (85%) for asians and a lower percentage (about 46%) for non-asians.

Thus, from the above data, it is believed that the lenses disclosed herein are significantly superior to lenses without grooves in enhancing tear exchange. In addition, from these data, it is believed that certain eyewear configurations are preferred for different or general populations having particular eye or eyelid anatomical physiological characteristics. In other words, lenses with one configuration of microchannels have been shown to increase tear exchange rates for asian subjects, while contact lenses with a different microchannel configuration, such as a reduced channel density or a greater distance between the microchannel apexes, have been shown to increase tear exchange rates for non-asian subjects.

While the invention has been described with respect to various specific examples and embodiments, it is to be understood that the invention is not limited to those embodiments, and that the invention may be variously embodied within the scope of the following claims.

Claims (61)

1. A contact lens for use on an eye, the lens comprising:

a lens body having a posterior surface and an anterior surface;

a plurality of micro-grooves formed on a rear side surface of the lens body, the plurality of micro-grooves forming a continuous wave shape in a ring direction; and

the lens body is configured to reduce the time required for exchange of tear fluid by at least 5% when the contact lens is worn on an eye, as compared to an identical contact lens without the plurality of microchannels.

2. The contact lens of claim 1 wherein the lens body is configured to reduce the time to exchange 95% of tear fluid by at least 15% when the contact lens is worn on the eye compared to an identical contact lens without the plurality of microchannels.

3. The contact lens of claim 1 wherein the lens body is configured to reduce the time to exchange 95% of tear fluid by at least 20% when the contact lens is worn on the eye compared to an identical contact lens without the plurality of microchannels.

4. The contact lens of claim 1 wherein the lens body is configured to reduce the time to exchange 95% of tear fluid by at least 25% when the contact lens is worn on the eye compared to an identical contact lens without the plurality of microchannels.

5. The contact lens of claim 1 wherein the lens body is configured to reduce the time to exchange 95% of tear fluid by at least 30% when the contact lens is worn on the eye compared to an identical contact lens without the plurality of microchannels.

6. The contact lens of claim 1 wherein the lens body is configured to reduce the time to exchange 95% of tear fluid by at least 35% when the contact lens is worn on the eye compared to an identical contact lens without the plurality of microchannels.

7. The contact lens of claim 1 wherein each of the plurality of microchannels is undulated in an annular direction.

8. The contact lens of claim 1 wherein at least two of the microchannels are undulated in an annular direction.

9. The lens of claim 1 wherein each of the plurality of microchannels is formed in an annular direction with a corrugation of no land portions.

10. The lens of claim 1 wherein the plurality of microchannels are formed in a substantially annular direction with a corrugation pattern having no land portions.

11. The lens of claim 1 wherein the plurality of microchannels define a continuous non-bonded portion of the wave pattern in the circumferential direction.

12. The contact lens of claim 1 wherein each of the microchannels comprises a microchannel that is devoid of bonded portions along at least a portion of the microchannel length.

13. The lens of claim 1 wherein each microchannel comprises a microchannel having no land along a major portion of the length of the microchannel.

14. The contact lens of claim 1 wherein the lens body comprises an optical zone free of the plurality of microchannels.

15. The contact lens of claim 1 wherein the plurality of microchannels comprise microchannels, each microchannel having a width in the range of 5-30 °.

16. The contact lens of claim 1 wherein the plurality of microchannels comprise between 3 and 200 microchannels.

17. The contact lens of claim 1 wherein the plurality of microchannels comprise between 10 and 100 microchannels.

18. The contact lens of claim 1 wherein the lens body is configured to increase tear mixing of the posterior lens tear film when the lens is worn on an eye of an asian person relative to tear exchange of the posterior lens tear film formed by a contact lens of substantially the same configuration worn on an eye of a non-asian person.

19. The contact lens of claim 1, wherein the lens body comprises a silicone hydrogel material.

20. A contact lens for use on an eye, the lens comprising:

a lens body having a posterior surface and an anterior surface;

a plurality of microchannels formed in a posterior surface of the lens body, each microchannel including a curved surface that is not concave relative to an anterior surface, the microchannels being sized and adapted to promote effective tear fluid exchange between an exposed surface of the eye and a surface of the eye covered by the lens body.

21. The contact lens of claim 20 wherein the lens body is configured to reduce the time to exchange 95% of tear fluid by at least 5% when worn on the eye compared to an identical contact lens without the plurality of channels.

22. The contact lens of claim 20 wherein the lens body is configured to reduce the time to exchange 95% of tear fluid by at least 15% when worn on the eye compared to an identical contact lens without the plurality of channels.

23. The contact lens of claim 20 wherein the lens body is configured to reduce the time to exchange 95% of tear fluid by at least 35% when worn on the eye compared to an identical contact lens without the plurality of channels.

24. The lens of claim 20 wherein the curved surface of each microchannel is convex with respect to the anterior surface.

25. The lens of claim 20 wherein the curved surface of each microchannel is continuously curved in the circumferential direction.

26. The lens of claim 20 wherein the lens body has a thickness that varies continuously along a radius extending from the optical axis of the lens body and circumferentially across at least a portion of each of the microchannels.

27. The lens of claim 20 wherein the lens body has a thickness that varies continuously along a radius extending from the optical axis of the lens body and circumferentially across a major portion of each of the microchannels.

28. The contact lens of claim 20 wherein the curved surface of each microchannel is located in a posterior region of the microchannel.

29. The lens of claim 20 wherein each microchannel is free of land along at least a portion of the length of the microchannel.

30. The lens of claim 20 wherein each microchannel is free of land along at least a major portion of the length of the microchannel.

31. The contact lens of claim 20 comprising an optical zone free of the plurality of microchannels.

32. The contact lens of claim 20 wherein the plurality of microchannels comprise microchannels, wherein each microchannel has a width in the range of 5-30 °.

33. The contact lens of claim 20 wherein the plurality of microchannels comprise between 3 and 200 microchannels.

34. The contact lens of claim 20 wherein the plurality of microchannels comprise between 10 and 100 microchannels.

35. The contact lens of claim 20 wherein the lens body is configured to enhance tear mixing of the posterior tear film of the lens when the contact lens is worn on an eye of an asian person as compared to tear mixing of the posterior tear film of the lens achieved by a contact lens of substantially the same configuration worn on an eye of a non-asian person.

36. The contact lens of claim 20 wherein the lens body comprises a silicone hydrogel material.

37. A contact lens for use on an eye, the lens comprising:

a lens body having a posterior surface and an anterior surface;

a plurality of microchannels formed in the posterior surface of the lens body, each microchannel being in contiguous relationship with one or more microchannels, the microchannels being sized and adapted to promote effective tear fluid exchange between the exposed surface of the eye and the surface of the eye covered by the lens body.

38. The contact lens of claim 37 wherein the time to exchange 95% of tear fluid is reduced by at least 5% when the contact lens is worn on the eye compared to an identical contact lens without the plurality of microchannels.

39. The contact lens of claim 37 wherein the time to exchange 95% of tear fluid is reduced by at least 15% when the contact lens is worn on the eye compared to an identical contact lens without the plurality of microchannels.

40. The contact lens of claim 37 wherein the time to exchange 95% of tear fluid is reduced by at least 35% when the contact lens is worn on the eye compared to an identical contact lens without the plurality of microchannels.

41. The lens of claim 37 wherein the lens body has a thickness that varies continuously along a radius extending from the optical axis of the lens body and spanning a substantial portion of each of the microchannels.

42. The lens of claim 37 wherein each microchannel comprises a microchannel having no land along a major portion of the length of the microchannel.

43. The contact lens of claim 37, wherein the contact lens comprises an optical zone without a plurality of microchannels.

44. The contact lens of claim 37 wherein the plurality of microchannels comprise microchannels, each microchannel having an angular width in the range of 5-30 °.

45. The contact lens of claim 37 wherein the plurality of microchannels comprise between 3 and 200 microchannels.

46. The contact lens of claim 37 wherein the plurality of microchannels comprise between 10 and 100 microchannels.

47. The contact lens of claim 37 wherein the lens body is configured to enhance tear mixing of the posterior tear film of the lens when the contact lens is worn on an eye of an asian person as compared to tear mixing of the posterior tear film of the lens achieved by an identical contact lens worn on an eye of a non-asian person.

48. The contact lens of claim 37, wherein the lens body comprises a silicone hydrogel material.

49. A contact lens for use on an eye, the lens comprising:

a lens body having a posterior surface and an anterior surface, including microchannels formed in the posterior surface, the microchannels forming a continuous wave pattern in a circumferential direction; and

the lens body is configured to enhance tear mixing of a posterior tear film of an individual of a target population of individuals when worn on an eye of said individual compared to the same contact lens worn on another individual of a different population.

50. The contact lens of claim 49 wherein the lens body is configured to enhance tear mixing of a posterior tear film of the lens in an individual of a population whose eye or eyelid characteristics are characteristic of the population.

51. The contact lens of claim 49 wherein the lens body is configured to enhance tear mixing of an individual's posterior tear film in a population having a high eyelid tension relative to a population of individuals.

52. The contact lens of claim 49 wherein the lens body is configured to enhance tear mixing when the contact lens is worn on an Asian individual's eye as compared to tear mixing achieved with an identical contact lens worn on a non-Asian individual's eye.

53. The contact lens of claim 49 wherein the lens body is configured to enhance tear mixing when the contact lens is worn on a non-Asian individual's eye as compared to tear mixing achieved with an identical contact lens worn on an Asian individual's eye.

54. The contact lens of claim 49 wherein the lens body comprises a silicone hydrogel material.

55. A silicone hydrogel contact lens, comprising:

a silicone hydrogel lens body having a posterior surface and an anterior surface and a thickness defined as the distance between the posterior surface and the anterior surface, and a plurality of radially extending microchannels defined in the posterior surface of the lens body and having a depth less than 90% of the thickness.

56. The contact lens of claim 55 wherein the lens body comprises from 3 to 200 microchannels.

57. The contact lens of claim 55 wherein the lens body comprises from 10 to 100 microchannels.

58. The lens of claim 55 wherein each microchannel has a tapered shape that tapers toward the optical axis of the lens body.

59. The lens of claim 55 wherein each microchannel has a maximum width proximate the lens body periphery.

60. The contact lens of claim 55 wherein the depth of the microchannels is less than 80% of the thickness of the lens body.

61. The contact lens of claim 55 wherein the depth of the microchannels is from about 0.1 microns to about 50 microns.