JP7208345B2 - contact lens - Google Patents

Description

CROSS-REFERENCES TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 62/083,198, filed November 22, 2014, which is hereby incorporated by reference in its entirety. .

TECHNICAL FIELD OF THE INVENTION: The present invention relates generally to the field of optical lenses and, more particularly, to lenses constructed to limit water permeability in at least one region of the lens while maintaining at least minimal oxygen permeability. directed at contact lenses. Maximum water permeability and minimum oxygen permeability are achieved with a single lens material at a given lens thickness or with the use of two or more layers of material.

The eye health of consumers who wear contact lenses is highly dependent on the amount of oxygen that permeates the lenses. Materials from which lenses are made are generally selected for their oxygen permeability coefficient, and numerous studies have been conducted to determine the minimum amount of oxygen required to maintain a healthy cornea.

The gas permeation coefficient, or oxygen permeation coefficient as this description applies, is mathematically described using the coefficient Dk, where D is the diffusion coefficient, which is a measure of how quickly oxygen moves through a material. (cm ² /sec) and k is the solubility coefficient (ml O ₂ /ml material×mmHg), which is a measure of how much oxygen is contained in the material. The coefficient of oxygen permeability (Dk/t or Dk/L) is derived by dividing the oxygen permeability coefficient of a material by the thickness of the material in centimeters.

The best transmission coefficients currently demonstrated in commercial lens products for the general public are in the range Dk=80-150×10 ⁻¹¹ (cm ² /sec) (mLO ₂ )/(mL×mmHg) (Barrer) is. The materials of these lenses are generally silicone acrylates or copolymers of silicone acrylates and hydrophilic monomers that yield silicone hydrogels. The former are typically hard lenses, while the latter are soft lenses. These lenses must be provided in thin designs to support corneal health, which can lead to problems related to durability, handling and, in the case of hydrogels, dehydration.

Dehydration, the loss of water from the interior of the lens, leads to changes in the lens geometry, reducing the lens diameter, thickness, and radius of curvature, and changing the lens optical power. , the lens exhibits poor wetting on the lens surface. Contraction of the lens can lead to tightness of the lens on the eye as indicated by reduced on-eye movement, while poor wetting leads to discomfort as the eyelid passes over the lens during blinking. There is Often the effects of dehydration are addressed by fitting a lens with a posterior lens radius of curvature that is longer than the underlying corneal curvature. Contraction of the lens then acts only to bring the lens into proper relationship with the eye while maintaining movement of the lens. To prevent discomfort, the lens may be surface treated to reduce the wetting angle and maintain a tear film in front of the lens, or the lens may ooze lubrication onto the surface to maintain comfort during wear. Prefilled with substance.

The above description generally applies to all lenses in commercial use today, with one important exception. An exception to this are lenses made of silicone rubber (crosslinked polydimethylsiloxane, PDMS). PDMS is attractive for use in contact lenses, firstly because of its extremely high oxygen permeability coefficient, which is more than twice that of the best competing materials, and secondly, PDMS is soft. , mechanical properties are similar to human tissue; third, PDMS has a long history of safe use as a biomaterial in implants and wound dressings; It is easily molded with a high transition of design features to, and finally, PDMS is not a hydrogel and therefore not susceptible to bacterial invasion.

Unfortunately, PDMS, which first appeared in contact lenses nearly 50 years ago, has not been successful in the general contact lens market. One reason is commonly described as the "sticking" problem, which is also described as "lens sticking." It is often observed that the lens does not move as little as 15 minutes after installation. In fact, early experience involved the actual adhesion of the lens to the cornea, leading to the loss of small pieces of epithelium upon removal of the lens. Such an event, although painful, was not vision-threatening because the cornea repairs itself relatively quickly, yet any disruption of the corneal surface presents an opportunity for infection.

PDMS lenses have lost their place in the general contact lens market, except for refractive correction of pediatric aphakia. Left untreated, this condition in infants invariably leads to blindness in the eye lacking the internal lens. Refractive treatment with PDMS contact lenses for pediatric aphakia is unique due to the need for extreme refractive power in contact lenses that require a thickness profile with a high central thickness. Sticking problems are rarely observed in such applications. Thick lenses are known to promote lens movement due to forced contact with the eyelid during blinking. Additionally, due to their high oxygen permeability, lenses for pediatric aphakia have regulatory approval for up to 30 days of continuous wear, thus eliminating the need for frequent lens removal, which , reducing the risk of desquamation of the epithelium.

Following the speculation of pediatric success with lenses with thick centers, there have been early efforts to address the lens sticking problem using techniques to improve lens surface wetting, typically plasma treatments. . Modified lens geometry designs with looser lens-to-eye relationships in conjunction with plasma-treated lenses have been explored without success. Dehydration of the lenses did not appear to be a possible cause of lens fouling, as the lenses contained little moisture (typically less than 0.2%).

PDMS contact lenses have a high oxygen solubility coefficient and a large oxygen diffusion coefficient (fraction of internal flux) (derived from the extremely high mobility of silicon atoms in the polymer), these properties leading to a very high oxygen permeability coefficient. (Dk). The transmission coefficient is effectively the product of these two properties. One property is the diffusion coefficient of the permeating species discussed above for oxygen. A second property is the solubility coefficient of the permeating species in the material through which it is permeating. A material with high values for both properties for a particular transmissive species will always have a high transmission coefficient for that transmissive species. Since PDMS has a very low water solubility coefficient, it is often assumed that water can be transported through the material at a slow rate. Given this assumption, it would be concluded that there is no possibility of shrinkage due to dehydration and that water transport by permeation is minimal. Strategies for minimizing water transport have not been recognized or reported as suitable approaches to solving the "sticking" problem.

It is recognized that the assumption of low water transport by PDMS by contact lens designers is erroneous and that water transport itself is the root cause of lens sticking which is the basis of this patent. Liquid water is barely detectable inside the PDMS lens, but water vapor molecules can freely pass through the material. In fact, while the oxygen permeability through this material is impressive, the water vapor permeability is more than 50 times higher. With a water permeability coefficient of this magnitude, it is possible to transport the entire tear volume from under the lens in a matter of minutes. Water depletion associated with the tear film behind the lens and the epithelial mucin layer can render both the lens and corneal surfaces hydrophobic, thereby increasing their attraction to each other. Such hydrophobic surface attraction will inevitably lead to lack of adhesion and movement. These effects are unlikely to be mitigated by surface treatments or loose-fitting lens design strategies. Some improvement may be observed in wearers such as infants, including closed-eye wear time with longer than normal exposure to the lenses.

A first possible solution to sticking would be to find another material with very high oxygen transmission but not rapid water transmission. Of course, such materials must have mechanical properties suitable for contact lenses, be manufacturable relatively inexpensively by low-cost processes such as cast molding that can be automated, and are suitable for the majority of patients. It would require a correspondingly smaller Stock Keeping Unit (SKU). New materials would have to be easy to fit, comfortable to wear, optically clear, non-toxic, and satisfactorily biocompatible. The search for such materials has been ongoing for nearly fifty years, and no material has yet been presented that meets all of these requirements. Lenses made of rigid, gas permeable materials have come closest, but are less comfortable to wear, difficult to fit, expensive to manufacture, and require larger stock keeping units.

Holden and Mertz describe the minimum requirements for maintaining normal corneal physiology for wearing contact lenses with the eyes open (all-day wear) and for wearing lenses during normal overnight sleep periods (long-wear or continuous wear). A standard for the oxygen transmission rate of

Holden and Mertz studied critical oxygen levels for avoiding corneal edema and defined them in terms of oxygen permeability and EOP. The relationship between corneal edema and the oxygen permeability of hydrogel lenses was investigated by measuring the corneal swelling response induced by different contact lenses over a 36 hour period of wear, comparing daily wear contact lenses with extended wear contact lenses. tested for both. The derived relationships allowed us to predict within ±1.0% the mean edema levels occurring with daily and long-term wear in the normal young adult population. The critical lens oxygen permeability required to avoid edema for daily wear contact lenses and extended wear contact lenses was obtained from the derived curves. Holden and ^Mertz reported an oxygen permeability ^{( Dk} / _t ), found that lenses with an EOP (Equivalent Oxygen Percentage) of 9.9% did not induce corneal edema.

The present disclosure addresses the problem through an alternative approach to making lenses that meet at least Holden Mertz's minimum standards for oxygen permeability while exhibiting no greater water transport than successful commercialized contact lenses. The present invention discloses a means for reducing water permeability while maintaining a minimum level of oxygen permeability. A first embodiment of the present invention provides a predetermined thickness to reduce the water permeability to a maximum acceptable level while maintaining the oxygen permeability of a very high permeability lens material to a minimum acceptable level. It is a lens with A second embodiment of the present invention is a lens comprising at least two materials, the combined materials providing maximum acceptable water permeability of the compound lens while maintaining at least minimal acceptable levels of oxygen permeability. configured into a single device to reduce it to the level possible.

So far, what appear to be parallel approaches have been considered in lenses called hybrid or compound lenses, which approaches (such as Saturn Lenses, Softperm Lenses, Synergeyes Lens branded lenses, etc.) It does not attempt to have constituent materials that work together by fusing, but rather uses dissimilar materials in different locations (side by side, in the center of the eye, and around the eye) to perform distinct functions. It was due to The present disclosure provides a series of materials that provide their combined properties to obtain the desired performance at the same location on the lens and therefore at the same location on the eye. The present disclosure constructs dissimilar materials in a "sandwich" or layered configuration with materials parallel to and perpendicular to the axis of the lens, rather than coaxial with the axis of the lens as in the compound or hybrid lenses described above.

The prior art also discloses lenses with anterior hard and posterior soft layers for the purpose of providing comfort of the lens when in contact with the eye while providing a rigid lens optic. Such laminated lenses do not address the problem of balancing maximum acceptable water permeability while maintaining at least a minimum oxygen permeability.

A further technical field teaches lenses with air cavities as well as cavities filled with fluid and gel materials, which challenge to limit the lens to maximum water permeability while maintaining minimum oxygen permeability. does not address The prior art also discloses the inclusion of components and elements in lenses that do not address the problem of balancing maximum acceptable water permeability while maintaining at least a minimum oxygen permeability.

It is an object of the present disclosure to provide contact lenses with minimal oxygen permeability for maintenance of normal corneal physiology for contact lens wear.

Another object of the present disclosure is to provide a contact lens with no more water transport than other successful commercial contact lenses.

It is a further object of this disclosure to provide a composite soft or hard contact lens that has at least a minimum acceptable level of oxygen permeability while having a composite lens water permeability that is less than a maximum acceptable level. .

The terms and phrases used in this document, and variations thereof, should be interpreted as open-ended as opposed to limiting, unless expressly specified otherwise. As an example of the above, the term "including" should be read to mean "including without limitation," etc., and the term "example" is an illustrative example of an item, not an exhaustive or limiting list thereof. are used in the description to provide examples, and the terms "a" or "an" should be read to mean "at least one," "one or more," etc., and "conventional," Adjectives such as "traditional," "usual," "standard," "well-known," and terms of similar import may be used to describe the item being described or the item being available at a given time. should instead be read to encompass any conventional, traditional, common or standard technology, which may be available or known at any time now or in the future is. Similarly, where this document refers to techniques that would be apparent or known to those of ordinary skill in the art, such techniques encompass techniques that would be apparent or known to those of skill in the art now or at any time in the future.

The presence of broad terms and phrases, such as "one or more," "at least," "but not limited to," or other similar phrases in some instances, precludes narrower instances in the absence of such broad phrases. It is not to be read to mean intended or required. Additionally, various embodiments described herein are described in terms of exemplary block diagrams, flow diagrams, and other examples. As will be apparent to one of ordinary skill in the art after reading this document, the illustrated embodiments and their various alternative embodiments can be implemented without being limited to the illustrated examples. For example, block diagrams and their accompanying descriptions should not be construed as implying a particular architecture or configuration.

Contact lenses as used herein are made from one or more films, including composite films. A composite film is a film composed of multiple films comprising multiple layers of films. In some, but not necessarily all, contact lenses are made exclusively from composite films, in which case the terms can also be used interchangeably.

Accordingly, the more important features of the invention have been outlined rather broadly so that the detailed description thereof may be better understood and its contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and form the subject of the claims appended hereto. The features recited herein and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims.

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. The drawings are not intended to be exhaustive or to limit the invention to the precise forms disclosed. It should be understood that the invention can be practiced with modification and alteration and that the invention is limited only by the claims and the equivalents thereof.

1A-1D are cross-sectional views of contact lenses having a first thickness and a second, greater thickness, according to selected embodiments of the present disclosure; 1A-1D are cross-sectional views of contact lenses having two layers with different permeability coefficients for oxygen and water vapor in accordance with selected embodiments of the present disclosure; 1A-1D are cross-sectional views of contact lenses having multiple layers with different permeability coefficients for oxygen and water vapor according to selected embodiments of the present disclosure; 1A-1D are cross-sectional views of contact lenses with outer lens material layers and inner material layers in accordance with selected embodiments of the present disclosure; 1A-1D are cross-sectional views of contact lenses having an outer lens material layer, an inner material layer, and an adhesive layer between the layers in accordance with selected embodiments of the present disclosure; 1A-1D are cross-sectional views of contact lenses having an outer lens material layer and an inner material layer that are staggered in some regions of the contact lens in accordance with selected embodiments of the present disclosure; Variations in the oxygen and water permeability coefficients of the composite as a fraction of their permeability coefficients initially represented by the total thickness of only one of the materials before including the second material layer and the first material layer is a chart of the change to the initial permeability coefficient by substituting a layer of equivalent partial thickness of a second material, where the second material has different oxygen and water vapor permeability coefficients. FIG. 10 is a chart of a first scenario in which the ratio of oxygen permeability coefficients (P _O1 /P _O2 ) is held constant; FIG. FIG. 5 is a chart of a second scenario in which the ratio of oxygen permeability coefficients (P _O1 /P _O2 ) is held constant;

Many aspects of the invention can be better understood with reference to the following drawings. Components in the figures are not necessarily drawn to scale. Instead, emphasis has been placed on clearly illustrating the elements of the invention. Further, like reference numerals denote corresponding parts throughout the several views of the drawings.

A first embodiment of the invention comprises a single lens material with very high oxygen and water vapor transmission coefficients. The thickness profile for the lens is selected to reduce water permeability below a maximum level while maintaining oxygen permeability above a minimum level. Fornasiero and co-workers (2005) measured steady-state diffusion of water through commercially successful hydrogel and silicone hydrogel lens materials, while Rofojo (1980) measured the steady-state diffusion of water through silicone rubber lens materials. was measured. Although the units of measure for the two studies are reported differently, conversions can be made to bring the water permeability coefficient into a common unit of measure.

In parallel, two lens thickness profiles of commercially successful lenses are known. The resulting water permeability is calculated as the water permeability coefficient divided by the thickness. It is worth noting that the water permeability coefficient varies with the ambient humidity of the material during the measurement. Additionally, the permeability coefficient may change as the hydrogel material dehydrates and becomes thinner. Even so, an average value for a range of ambient humidity can be used for the purposes of this disclosure.

The water permeability coefficient can be reported in μg/μm cm ² s ⁻¹ or in cm/μm and can be converted to cm ³ /μg H ₂ O and mmHG/Atm, which is then converted to Barrer be able to. Such a conversion allows comparison of conventional hydrogel and silicone hydrogel measurements of water permeability coefficient with reported values for the water permeability coefficient of silicone rubber materials. The table below presents reported values for comparison:

Previous reports of lens thickness for polymacon include commercialized lenses ranging in center thickness values from 0.04 to 0.18 mm. The majority of lenses have a central thickness value between 0.08 and 0.12 mm or an average of 0.10 mm. Lenses made of polymacon have been demonstrated to have been in continuous use for over 50 years without reports of lens deposits. Studies of the long-term commercial success of polymacon lenses and the lack of reports of lens adhesion or "sticking" suggest that the water vapor transmission rate is sufficiently low to prevent depletion of the tear film behind the lens. It is noteworthy that polymacon also has a low oxygen permeability coefficient, falling below the Holden Mertz criteria for delivery of oxygen for open eye wear, and therefore constitutes a small percentage of the new fit.

The disclosure herein provides one implementation of the use of predetermined lens thicknesses to reduce water permeability to the approximate levels demonstrated by polymercon lenses while maintaining oxygen permeability above the Holden Mertz criteria for open eye wear. Provide as a form. The Holden Mertz value set as the minimum oxygen permeability (Dk/t) for the lenses of the invention is 24.1±2.7×10 ⁻⁹ (cm ³ O ₂ )/(cm ² ·s·mmHg). is. For example, one variant of polydimethylsiloxane is reported to have Dk=340×10 ⁻¹¹ (cm ² /sec) (mLO ₂ )/(mL×mmHg). Other variants of the same material may have higher or lower Dk measurements.

A lens made of a material with Dk=340×10 ⁻¹¹ (cm ² /sec) (mLO ₂ )/(mL×mmHg) has Dk/t=24.1×10 ⁻⁹ (cm×mlO ₂ ). It can also have a center thickness as large as 0.141 cm to maintain /(sec×ml×mmHg). Although this is an order of magnitude greater than commercialized lenses, the oxygen permeability would be expected to meet open eye (day wear) requirements. Such a thickness would also reduce the water permeability of the same lens to levels well below those demonstrated by commercially successful polymacon and silicone hydrogel lenses.

A lens thickness of 1.41 mm is excessive and unprecedented, so the present invention is directed to minimizing the thickness to achieve a water permeability substantially equal to that of polymercon. A harmonic thickness value for a polymacon lens of 0.08 mm is chosen to produce the limiting maximum water permeability for the present invention. By way of example only, the water permeability of polymacon at 50% humidity is 11,110, which translates to Barrer's permeability coefficient. Using the harmonic thickness of the lens as 0.008 cm, the water permeability (B/t) of the exemplary lens is found to be 13,887.5. Continuing the example, the reported permeability coefficient value for the polydimethylsiloxane variant is found to be 40,000 Barrer. To achieve one embodiment of the lens of the present disclosure, the lens thickness (t) to achieve B/t=13887.5 in a material with a Barrer water permeability coefficient of 40,000 is 0.029 cm , which is more than three times as thick as the average lens made of hydrogel and silicone hydrogel materials. In certain embodiments, contact lenses have an average thickness greater than 0.4 mm. In another embodiment, the contact lens has an average thickness greater than 0.3 mm. In yet another embodiment, the contact lens has an average thickness greater than 0.2 mm.

Certain embodiments of the present disclosure provide lenses having a predetermined thickness of the lens region over most of the corneal surface regardless of lens power. It has a higher thickness only at the geometric center of the lens and the convex curvature of the anterior surface of the lens has a greater radius than the concave curvature of the posterior surface for the purpose of providing a high positive refractive power to correct aphakia. This is unlike the previously mentioned lenses made of polydimethylsiloxane, which thin rapidly due to the short . By way of example only, a lens of the present invention with no power, with parallel surfaces, or with normal power for correction of ametropia, has a power of 24.1±2.7×10 ⁻⁹ (cm * ml O ₂ )/(sec×ml×mmHg) or greater, while providing a water permeability not exceeding B/t=13887.5 Barrers/cm while providing an oxygen permeability Dk/t.

The most favorable solution to the high water transport dilemma associated with high oxygen permeability is to essentially reduce the permeability coefficients for these components such that both oxygen and water transport are in line with physiological demands. It should be recognized by those skilled in the art of contact lens design and manufacture that the material will have a Of course, such materials must also meet all the requirements necessary for an acceptable contact lens (biocompatibility, good wetting, adequate mechanical properties, non-toxicity, durability, and cost effectiveness). Those skilled in the art should understand that. Research towards this goal continues to this day, but no such product has been reported, even after 50 years of research.

Hence, the above-proposed embodiment provides one solution to the dilemma, while alternative embodiments provide different solutions that each meet some of the requirements for lens acceptability in complex configurations. It provides a different approach by which materials are employed, where the individual limitations of the combined materials are relaxed by the extent and/or position within the final product where the ingredients are placed. For example, mechanical limitations can be alleviated by the use of minimal lens thickness, biocompatibility, or a 'sandwich' of materials that behave better in these aspects, or the tear film volume behind the lens. can be mitigated by isolating such components within.

であり、ここで、Ｐは、複合材の規定の透過種に対する透過係数であり、Ｅ_ｉは、ｉ番目の層の厚さであり、Ｐｉは、同じ透過種に対するｉ番目の層の透過係数であり、Ｅ_ｔは、複合材のｍｍの全厚である。透過係数は、好ましくは同様の方法により導出される同じ単位で表されなければならない。したがって、新しい透過係数は、関心ある透過種のそれぞれに関して複合材ごとに導出することができる。さらに、各透過種に関して、該透過種に関する最高の透過係数を有する材料のその初めの透過係数のフラクションとして、その修正された透過係数を表すことが都合がよい。これは、材料を他の材料層とサンドイッチすることにより該透過種に関して受け入れられる中間物を表す。 More particularly, an alternative embodiment of the present invention consists of at least two separate layers arranged such that the more biocompatible layer is the element that contacts the anterior and posterior tear layers. It is a lens that has been Elements with less desirable mechanical properties or oxygen permeability will be placed in thin layers. The relative thicknesses of the individual layers within the sandwich will be imposed in relation to the oxygen and water permeability coefficients of the individual materials. The determining factors for the relative thicknesses will be their summed permeation coefficients for oxygen and water vapor, while trying to keep the maximum oxygen and water vapor permeation coefficients. This is not the arithmetic sum of the permeation coefficients, but rather their appropriately summed properties, with the recognition that the summed properties actually represent the resistance to permeation, as opposed to the amount of permeation allowed. It is important to note that . A suitable formula is

where P is the permeability coefficient of the composite for a given permeating species, Ei is the thickness of the _i -th layer, and Pi is the permeation coefficient of the i-th layer for the same permeating species and E _t is the total thickness of the composite in mm. The transmission coefficients should preferably be expressed in the same units derived by a similar method. Therefore, new transmission coefficients can be derived for each composite for each transmission species of interest. Furthermore, for each transmitting species, it is convenient to express its modified transmission coefficient as a fraction of its original transmission coefficient of the material with the highest transmission coefficient for that transmission species. This represents an acceptable intermediate for the permeating species by sandwiching the material with other layers of material.

In certain embodiments, it is desirable to maintain a constant thickness of the sandwiched layers in the lens. In alternate embodiments, the thickness of the layers may be varied within the sandwich. Merely by way of example, the contact lenses of the present disclosure have been shown to improve the delivery of oxygen to the cornea, although the lack of oxygen across the corneal border may be less of an issue where some oxygen is supplied by the underlying vasculature. may be required to be more important. Conversely, water loss from the tear pool under the lens is equally adversely affected by water loss through the periphery of the lens as opposed to the center. The peripheral area for water loss is inherently wider than the central area of the lens. Total loss of the tear pool can be substantially affected if the peripheral region has a thicker sandwiched layer that resists water transport despite the concomitant loss of oxygen transport, whereas The reduction in oxygen availability will be mitigated by the lower need for oxygen under the periphery of the lens and the availability of alternative sources.

Sandwich fabrication requires bonding of individual layers, and adhesive films may be required between the primary layers. The permeability coefficients of these adhesive films are chosen such that, at the very thin films required for adhesion, they will have a small effect on the overall permeability coefficient of the composite. However, if they have a greater influence, they should also be included in the calculation of the composite's permeability coefficient. In rare cases to obtain good adhesion, a thin conforming layer is placed between the primary layers so that the sandwich consists of a primary layer and a secondary layer and all such layers are separated by an adhesive film. may need to be inserted. Also, the final composite permeability coefficient will be derived by the formula given above. when the primary layers are essentially adhesive to each other or to the inner layer, when they are simply wrapped in an outermost layer which is adhered around it by an adhesive where it extends slightly beyond the inner layer, or In other cases, such as when it is actually an extension of the single surrounding layer of the outermost layer formed during the molding process, there may be no need for adhesive.

Ｔは、複合材の全厚であり、ｆは、最も高い酸素透過係数を有する材料が占める複合材の厚さのフラクションであり、Ｐ_ＯＣは、複合材の酸素透過係数であり、Ｐ_Ｏ１は、第１の材料の酸素透過係数であり、Ｐ_Ｏ２は、第２の材料の酸素透過係数であり、Ｐ_ＷＣは、複合材の水透過係数であり、Ｐ_Ｗ１は、第１の材料の水蒸気透過係数であり、Ｐ_Ｗ２は、第２の材料の水蒸気透過係数である。 The process of selecting the composition and thickness of the layers of the sandwich is most conveniently performed using the derivative of the equations given above. As an example, consider the permeation of oxygen and water through a sandwich consisting of two outer layers of one material and one inner layer of another material. In addition, the two materials have different ratios of oxygen and water permeability coefficients, and in one material the relative water permeability coefficient makes water permeation significantly more favorable than oxygen permeation, whereas in the second It is considered that the permeability coefficient of water is greatly reduced with respect to the permeability coefficient of oxygen in this material. The aim is to produce a composite sandwich of two materials in which the water permeability is substantially reduced relative to the oxygen permeability, the overall result being that the composite has a water permeability of only the first layer. , while the residual level of reduced oxygen transport remains within acceptable levels over the intended lens wear schedule. Depending on the initial magnitude of the oxygen permeability coefficient, the initial oxygen permeability fraction can be selected for interest and the remaining water permeability fraction calculated. These calculations are illustrated below:

T is the total thickness of the composite, f is the fraction of the composite thickness occupied by the material with the highest oxygen permeability, _POC is the oxygen permeability of the composite, and _PO1 is , is the oxygen permeability coefficient of the first material, _PO2 is the oxygen permeability coefficient of the second material, _{PWC is the water permeability coefficient of the composite, and PW1 is} the water vapor permeability of the first material. is the permeability coefficient and _PW2 is the water vapor permeability coefficient of the second material.

Using literature values of water and oxygen permeability coefficients for polydimethylsiloxane and amorphous Teflon at 1 mm thickness, _PO1 is the oxygen permeability coefficient of polydimethylsiloxane and _PO2 is the oxygen permeability coefficient of amorphous Teflon. , _PW1 is the water vapor transmission coefficient of polydimethylsiloxane and _PW2 is the water vapor transmission coefficient of amorphous Teflon. From these values, the composite can reduce the water permeability to just over 10% of that of pure PDMS, while maintaining the oxygen permeability above 80% of that of pure PDMS.

FIG. 7 is a chart of the variation of oxygen and water permeability coefficients of composites. Although the absolute values of the fractions as represented by the endpoints of the chart are controlled by the absolute transmission coefficient values of the two components, another very important feature of these values appears in this chart. This feature is the asymmetry of the two functions. The oxygen permeability coefficient regresses relatively linearly from its high point when none of the second components is at its low point when only the second component is present, whereas the water permeability function is , behaves quite differently. The water permeability coefficient of the composite relative to that of the first component drops sharply upon initial inclusion of a much thinner layer of the second component. Such asymmetry allows for excellent enhancement of the water permeability coefficient with a small effect on the oxygen permeability coefficient of the composite compared to the first material. A very thin layer of the second material is sufficient to greatly reduce the excessive water permeability of the first material while preserving the excellent oxygen permeability of the first material.

The aspect of the permeability coefficient employed in this composite that is most responsible for the favorable asymmetry in this result is the ratio of the oxygen permeability coefficient of the first material to the oxygen permeability coefficient of the second material (P _O1 /P _O2 ). The difference in the ratio of the water permeability coefficient of the first material to the water permeability coefficient of the second material (P _W1 /P _W2 ) compared. The greater the difference, the greater the asymmetry. In this particular case, where it is desirable to preserve the oxygen permeability coefficient and at the same time reduce the water permeability coefficient, the oxygen permeability coefficient is reduced with a substantially greater ratio of the water permeability coefficients (P _W1 /P _W2 ). The selection of the second material keeping the ratio (P _O1 /P _O2 ) small successfully increases the water permeability coefficient with a small reduction in the oxygen permeability coefficient due to the inclusion of a very thin layer of the second material within the first material. This leads to a relatively large reduction.

FIG. 8 shows a chart for a first scenario in which the ratio of oxygen permeability coefficients (P _O1 /P _O2 ) is held constant, but the ratio of water permeability coefficients (P _W1 /P _W2 ) is greater than in FIG. . FIG. 9 shows a chart for a second scenario in which the ratio of oxygen permeability coefficients (P _O1 /P _O2 ) is held constant, but the ratio of water permeability coefficients (P _W1 /P _W2 ) is smaller than in FIG. . In these two charts, where the ratio of oxygen permeability coefficients (P _O1 /P _O2 ) is held constant, it can be seen that the ratio of water permeability coefficients (P _W1 /P _W2 ) is different in the two alternative cases ( one less positive and one more positive). It is observed that the more positive the ratio, the greater the favorable asymmetry in the function.

In certain embodiments, the medium, ie, the second component or material within the first material, has a water permeability coefficient less than 10,000 Barrer and an oxygen permeability coefficient greater than 200 Barrer. Another embodiment provides an oxygen transmission rate higher than a minimum value such as 24.1×10 ⁻⁹ (cm×mlO ₂ )/(sec×ml×mmHg) while providing an oxygen permeability higher than a maximum value such as 13887.5 Barrer/cm. Provide an area of the composite film measured in excess of 50 square millimeters of the contact lens with a medium thickness that yields even lower water permeability.

As noted above, the ratio of the penetrating species for a particular penetrating species is the ratio of the permeability coefficient for the penetrating species of the first material (eg, P _O1 ) to the permeability coefficient for the penetrating species of the second material (eg, P _O2 ). is calculated by taking In certain embodiments, the contact lens has different ratios of transmission coefficients of the two transmitting species. As indicated above, the compositions of the two different layered materials can be selected such that the ratio of the second penetrating species is greater than the ratio of the first penetrating species. For example, a contact lens can have a ratio of a first permeant species to the permeant species oxygen that is less than a ratio of a second permeant species to the permeant species water (or water vapor). In certain embodiments, the composition of the layered material is selected such that the ratio of the first penetrating species is 5 or less and the ratio of the second penetrating species is 10 or more. In another embodiment, the ratio of the first penetrating species is 3 or less and the ratio of the second penetrating species is 20 or greater. In yet another embodiment, the ratio of the first penetrating species is 2 or less and the ratio of the second penetrating species is 30 or greater.

The difference between the transmission coefficient of the transparent species of the composite contact lens and the transmission species of the layered material can be expressed as a percentage difference. In certain embodiments, the composition of the medium and the thickness of the layers of the medium are such that the permeability coefficient for the first permeable species, such as oxygen, of the composite contact lens is for the first permeable species, such as crosslinked polydimethylsiloxane, of the primary material. It may be chosen to be no less than 20 percent of the transmission coefficient. In another embodiment, the permeability coefficient for the first permeable species of the composite film is no less than 50 percent of the permeability coefficient for the first permeable species of the primary material. In yet another embodiment, the permeability coefficient for the first penetrating species of the composite film is no less than 75 percent of the permeability coefficient for the first penetrating species of the primary material. In yet another embodiment, the permeability coefficient for the first permeable species of the composite film is no less than 90 percent of the permeability coefficient for the first permeable species of the primary material. In yet another embodiment, the permeability coefficient for the first penetrating species of the composite film is no less than 95 percent of the permeability coefficient for the first penetrating species of the primary material.

Another embodiment has a permeability coefficient for the second permeable species, such as water or water vapor, of the composite film that does not exceed 95 percent of the permeability coefficient for the second permeable species of the primary material, such as crosslinked polydimethylsiloxane. In another embodiment, the permeability coefficient of the second permeable species of the composite film does not exceed 90 percent of the permeability coefficient for the second permeable species of the primary material. In a further embodiment, the permeability coefficient for the second permeable species of the composite film does not exceed 75 percent of the permeability coefficient for the second permeable species of the primary material. In yet another embodiment, the permeability coefficient of the second permeable species of the composite film does not exceed 50 percent of the permeability coefficient for the second permeable species of the primary material. In a further embodiment, the permeability coefficient for the second permeable species of the composite film does not exceed 25 percent of the permeability coefficient for the second permeable species of the primary material. In a further embodiment, the permeability coefficient for the second permeable species of the composite film does not exceed 10 percent of the permeability coefficient for the second permeable species of the primary material.

Reference is now made to FIG. 1, which shows a contact lens 100 according to selected embodiments of the present disclosure. Contact lens 100 has a first thickness 101 approximating a conventional contact lens thickness bounded by a first anterior surface 102 and the same thickness for the purpose of reducing the water permeability of the finished lens to the limits of the present disclosure. It has an additional lens thickness 103 of material. In certain embodiments, the first lens thickness 101 is a primary material film and the additional lens thickness 103 is the same primary material film, the primary material film being a polymer containing crosslinked polydimethylsiloxane, or At least partially made of alternative materials with a Dk of 200 Barrer or greater.

As will be appreciated by those of ordinary skill in the art, certain embodiments of the present disclosure may be applied to locations on the anterior surface, to symmetrical configurations, to uniform thickness profiles, or to centered relative to the geometric center of contact lens 100. It may have an additional thickness 103 that is not limited to the location where it is biased towards. For example, additional thickness may be used symmetrically or asymmetrically, or localized placement may be used. As such, the lens can be customized to include several different thickness profiles to provide the desired oxygen and water permeability of the finished contact lens 100 . Further, the first thickness 101 and the additional lens thickness 103 can be one continuous element or two separate layers each having an encapsulated component with a surface in contact with the other. can be

FIG. 2 shows a contact lens 200 according to selected embodiments of the present disclosure. The contact lens 200 comprises a first material film 201 bounded by a first material boundary 202 and a second material film 201 bounded by an anterior surface 204 for the purpose of reducing the water permeability of the finished lens to the limits of this disclosure. of material film 203 . In certain embodiments, the first material film 201 is a primary material film and the additional lens thickness 203 is a layered secondary material film, wherein the layered primary material film or the layered secondary material film is is made at least partially from a polymer containing crosslinked polydimethylsiloxane or an alternative material with a Dk of 200 Barrer or greater.

As will be appreciated by those of ordinary skill in the art, certain embodiments of the present disclosure may be applied to a position on the anterior surface, a symmetrical configuration, a uniform thickness profile, or centered relative to the geometric center of the contact lens 200. may have secondary material film 203 that is not limited to a location that is biased toward the For example, a secondary material film may be used behind or in front of a primary material film. Secondary material films may be used symmetrically or asymmetrically, or a localized arrangement may be used. Thus, the lens can be customized to include several different primary and secondary material film thickness profiles to provide the desired oxygen permeability and water permeability of the finished contact lens 200 . . Further, the first thickness 201 and the additional lens thickness 203 can be one continuous element or two separate layers each having an encapsulated component with a surface in contact with the other. can be

FIG. 3 shows a cross section of a segment of a contact lens 300 according to selected embodiments of the present disclosure. The multilayer contact lens 300 has an anterior layer 301 , a posterior layer 302 , a first inner layer 303 , a second inner layer 304 and a third inner layer 305 . Contact lens 300 demonstrates an associated water permeability in the direction of arrow 306 from the environment behind rear layer 302 toward the environment ahead of front layer 301 .

With continued reference to FIG. 3, contact lens 300 demonstrates an associated oxygen permeability in the direction of arrow 307 from the environment anterior to anterior layer 301 toward the environment posterior to posterior layer 302 . As will be appreciated by those of ordinary skill in the art, certain embodiments of the present disclosure may be applied to a number, to local positions within or at an apparent relative depth in lens 300, to symmetrical configurations, to uniform The layers may have a thickness profile that is not limited to a uniform thickness profile or a position centered with respect to the geometric center of the contact lens 300 . For example, fewer or additional layers, or deeper or shallower arrangements of layers may be used, or local arrangements may be used. As such, the lens can be customized to include a number of different layers, the thickness of which can be determined to provide the desired oxygen and water permeability.

FIG. 4 shows a cross section of a layered contact lens 400 according to selected embodiments of the present disclosure. Layered contact lens 400 has a first material 401 and a second material layer 402 . The second material layer 402 of the contact lens 400 has a variable thickness profile and is positioned over a region of the contact lens 400 . In certain embodiments, first material 401 is a layered primary material film and second material layer 402 is a layered secondary material film. The layered primary material film is at least partially made from a polymer containing silicone acrylate. Alternatively, the layered primary material film is at least partially made from a polymer containing crosslinked polydimethylsiloxane or an alternative material with a Dk of 200 Barrer or greater. Layered secondary material films are made from films having a water permeability coefficient of less than 10,000 Barrer, such as amorphous or crystalline fluorocarbon-containing films. Alternatively, the layered secondary material film is made from a polyurethane-containing film having a water permeability coefficient of less than 10,000 Barrer. In yet another alternative embodiment, the layered secondary material film is made from at least a silicone-containing film having a water permeability coefficient of at least less than 10,000 Barrer.

With continued reference to FIG. 4, second material 402 is thicker at its center and thinner at its peripheral edges. Contact lens 400 includes a rear layer of first material 401, which lies behind second material layer 402 and has a uniform thickness. In addition, contact lens 400 includes an anterior layer of first material 401 that is in front of second material 402 and is thinner at its center and thicker at the central periphery of the anterior layer. As will be appreciated by those of ordinary skill in the art, certain embodiments of the present disclosure are useful in number, in their location in apparent thickness within contact lens 400, in symmetrical configuration, in uniform thickness profile, or provide a layer that is not limited to a position centered with respect to the geometric center of the contact lens 400 . For example, additional layers or deeper or shallower arrangements of layers may be used, or local arrangements may be used. As such, the lens can be customized to include a number of different layers, the thickness of which can be determined to provide the desired oxygen and water permeability.

FIG. 5 shows a cross-section of a layered contact lens 500 according to selected embodiments of the present disclosure. Layered contact lens 500 has first material 501 , second material layer 502 , and adhesive layer 503 . A contact lens second material layer 502 has a variable thickness profile and is disposed in a region of the contact lens 500 .

With continued reference to FIG. 5, second material 502 is thicker at its center and thinner at its peripheral edges. Contact lens 500 includes a rear layer of first material 501, which lies behind second material layer 502 and has a uniform thickness. In addition, contact lens 500 includes an anterior layer of first material 501 that is in front of second material 502 and is thinner at its center and thicker at the central periphery of the anterior layer. Adhesive layer 503 surrounds second material layer 502 . In an alternative embodiment, the adhesive layer 503 may not cover the second layer and may be applied only to one partial surface of the area of the second layer.

As will be appreciated by those skilled in the art, certain embodiments of the present disclosure provide one or more adhesives that have the same or different relative permeability coefficients and can be applied in an overlapping manner or topically. In addition, the layers may be arranged in number, in their position at apparent thickness within the contact lens 500, in a symmetrical configuration, in a uniform thickness profile, or centrally with respect to the geometric center of the contact lens 500. It may not be limited to the submitted position. For example, additional layers or deeper or shallower arrangements of layers may be used, or local arrangements may be used. As such, the lens can be customized to include a number of different layers, the thickness of which can be determined to provide the desired oxygen and water permeability.

FIG. 6 shows a cross-section of a layered contact lens 600 according to selected embodiments of the present disclosure. Layered contact lens 600 has a first material 601 , a second material layer 602 and a third material 603 surrounding the second material 602 . Second material 602 has a relatively uniform thickness profile and is disposed in the central region of contact lens 600 . Layer 602 may alternatively have the same composition as layer 601 . A third material 603 has a variable thickness and is disposed in the central peripheral region of the contact lens 600 .

With continued reference to FIG. 6, second material 602 is relatively uniform in thickness. The third material 603 is thicker at its center and thinner at its peripheral edges. Contact lens 600 includes a rear layer of first material 601 , which has a relatively uniform thickness and lies behind second material layer 602 and third material layer 603 . In addition, the contact lens 600 includes an anterior layer of a first material 601 that is thinner at its center and thicker at the central periphery of the anterior layer and anteriorly of a second material 602 and a third material 603 . It is in.

As will be appreciated by those of ordinary skill in the art, certain embodiments of the present disclosure can be applied to the number, their location in the apparent thickness within the contact lens 600, the symmetrical configuration, the uniform thickness profile, or provide a layer that is not confined to a position centered with respect to the geometric center of the contact lens 600 . For example, additional layers or deeper or shallower arrangements of layers may be used, or local arrangements may be used. As such, the lens can be customized to include a number of different layers, the thickness of which can be determined to provide the desired oxygen and water permeability.

Various fabrication methods may be used to produce the composite films and contact lenses disclosed herein. For example, contact lenses may be fabricated at least in part by molding, including cast molding and compression molding. Melt pressing and solution casting methods may be practiced, at least in part, in fabricating contact lenses. Additionally, the contact lens may be at least partially fabricated by lathing.

Different materials that make up the material films, composite films, and/or contact lenses can have different moduli. A material's modulus, or more specifically its modulus, is a measure of a material's resistance to being elastically deformed. In certain embodiments, the modulus of the primary material film is greater than the modulus of the secondary material film. In an alternative embodiment, the modulus of the primary material film is less than the modulus of the secondary material film.

In addition to providing a contact lens with a minimum permeability for the penetrating species oxygen, the contact lens may also have a minimum permeability for the penetrating species such as carbon dioxide. In such cases, the layers of material film and/or the thickness of the contact lens are set for minimum carbon dioxide permeability instead of or in addition to minimum oxygen permeability.

The same principles discussed above also provide for delivery of therapeutic agents. The therapeutic agent delivery device comprises a composite film comprising one or more layered primary material films and one or more layered secondary material films, the composite film having a thickness, a first permeable species and a permeability coefficient for a second penetrating species, the primary material film and the secondary material film having a thickness, a permeability coefficient for the first penetrating species, and a permeability coefficient for the second penetrating species, respectively and the composite thickness includes the combined thickness of the primary material layer and the secondary material layer, and the primary film thickness and the secondary film thickness are related to the first permeable species of the composite film The difference between the permeability coefficient of the primary material film and the permeability coefficient for the first penetrating species is less than the difference between the permeability coefficient of the second penetrating species of the composite film and the permeability coefficient of the second penetrating species of the primary material film. to be made. In such embodiments, the second penetrating species is a therapeutic agent.

While various embodiments of the invention are described herein in some detail, it is intended that the disclosure be made by way of example only and that the following claims and their reasonable equivalents are considered to be the invention. It should be understood that modifications and variations may be made to this disclosure without departing from subject matter within its scope.

The present invention includes the following aspects.
[1]
A composite film comprising a primary material film and a secondary material film,
the composite film has a thickness, a permeability coefficient for a first penetrating species, and a permeability coefficient for a second penetrating species;
said primary material film and said secondary material film each having a thickness, a permeability coefficient for a first penetrating species, and a permeability coefficient for a second penetrating species;
the thickness of the composite includes the total thickness of the primary material film and the secondary material film;
The thickness of the primary material film and the thickness of the secondary material film are such that the difference between the permeability coefficient for the first penetrating species of the composite film and the permeability coefficient for the first penetrating species of the primary material film is the composite is made smaller than the difference between the permeability coefficient of the film for the second permeable species and the permeability coefficient for the second permeable species of the primary material film;
composite film.
[2]
The composite film according to [1], wherein the thickness of the secondary material film is smaller than the thickness of the primary material film.
[3]
A first permeable species ratio is the ratio of the permeation coefficient for the first permeable species of the primary material film to the permeation coefficient for the first permeable species of the secondary material film, and the ratio of the second permeable species is the ratio of the permeation coefficient for the second permeable species of the primary material film to the permeation coefficient for the second permeable species of the secondary material film, wherein the ratio of the second permeable species is the ratio of the first permeable species The composite film of [1], which is greater than the species ratio.
[4]
The composite film of [3], wherein the ratio of the second penetrating species is 10 or more and the ratio of the first penetrating species is 5 or less.
[5]
The composite film of [3], wherein the ratio of the second penetrating species is 20 or more and the ratio of the first penetrating species is 3 or less.
[6]
The composite film of [3], wherein the ratio of the second penetrating species is 30 or more and the ratio of the first penetrating species is 2 or less.
[7]
The composite film of [1], wherein the composite film has a permeation coefficient for the first permeable species that is no less than 95 percent of the permeation coefficient for the first permeable species of the primary material film.
[8]
The composite film of [1], wherein the composite film has a permeation coefficient for the first permeable species that is no less than 90 percent of the permeation coefficient for the first permeable species of the primary material film.
[9]
The composite film of [1], wherein the composite film has a permeation coefficient for the first permeable species that is no less than 75 percent of the permeation coefficient for the first permeable species of the primary material film.
[10]
The composite film of [1], wherein the composite film has a permeation coefficient for the first permeable species that is no less than 50 percent of the permeation coefficient for the first permeable species of the primary material film.
[11]
The composite film of [1], wherein the permeability coefficient of the second permeable species of the composite film does not exceed 25 percent of the permeability coefficient for the second permeable species of the primary material film.
[12]
The composite film of [1], wherein the composite film has a permeation coefficient for a second permeable species that does not exceed 50 percent of the permeation coefficient for the second permeable species of the primary material film.
[13]
The composite film of [1], wherein the composite film has a permeation coefficient for a second permeable species that does not exceed 75 percent of the permeation coefficient for the second permeable species of the primary material film.
[14]
The composite film of [1], wherein the composite film has a permeation coefficient for a second permeable species that does not exceed 90 percent of the permeation coefficient for the second permeable species of the primary material film.
[15]
The composite film of [1], wherein the composite film has a permeation coefficient for a second permeable species that does not exceed 95 percent of the permeation coefficient for the second permeable species of the primary material film.
[16]
The composite film of [1], wherein the first permeable species is oxygen.
[17]
The composite film of [1], wherein the first permeating species is carbon dioxide.
[18]
The composite film of [1], wherein the second permeating species is water or water vapor.
[19]
The composite film of [1], wherein the primary material film is a polymer containing crosslinked polydimethylsiloxane.
[20]
The composite film of [1], wherein the primary material film is a polymer containing silicone acrylate.
[21]
The composite film of [1], wherein the secondary material film is an amorphous or crystalline fluorocarbon-containing film.
[22]
The composite film of [1], wherein the secondary material film is a polyurethane-containing film.
[23]
The composite film of [1], wherein the secondary material film is a silicone-containing film.
[24]
The composite film according to [1], wherein the primary material film and the secondary material film each have a modulus, and the modulus of the primary material film is higher than the modulus of the secondary material film.
[25]
The composite film according to [1], wherein the primary material film and the secondary material film each have a modulus, and the modulus of the primary material film is smaller than the modulus of the secondary material film.
[26]
A contact lens comprising a composite film,
the composite film comprises a layered primary material film and a layered secondary material film;
the composite film has a thickness, a permeability coefficient for a first penetrating species, and a permeability coefficient for a second penetrating species;
said primary material film and said secondary material film each having a thickness, a permeability coefficient for a first penetrating species, and a permeability coefficient for a second penetrating species;
the thickness of the composite includes the total thickness of the primary material film and the secondary material film;
The thickness of the primary material film and the thickness of the secondary material film are such that the difference between the permeability coefficient for the first penetrating species of the composite film and the permeability coefficient for the first penetrating species of the primary material film is the composite is made smaller than the difference between the transmission coefficient of the second transmission species of the film and the transmission coefficient of the second transmission species of the primary material film;
contact lens.
[27]
said contact lenses have an average thickness greater than 0.4 millimeters [26]
The contact lens described in .
[28]
said contact lenses have an average thickness greater than 0.3 millimeters [26]
The contact lens described in .
[29]
said contact lenses have an average thickness greater than 0.2 millimeters [26]
The contact lens described in .
[30]
The contact lens of [26], wherein the contact lens is a soft contact lens.
[31]
The contact lens of [26], wherein the contact lens is a hard contact lens.
[32]
The contact lens of [26], wherein said first penetrating species is oxygen.
[33]
The contact lens of [26], wherein said second penetrating species is water or water vapor.
[34]
The contact lens of [26], wherein the primary material film is a polymer containing crosslinked polydimethylsiloxane.
[35]
a contact lens,
an anterior surface facing away from the eye;
a posterior side facing toward the eye, and
a medium between the anterior surface and the posterior surface and having an oxygen permeability coefficient and a water permeability coefficient;
a thickness of the medium that provides a water permeability lower than the maximum while providing an oxygen permeability higher than the minimum;
wherein the maximum water permeability is 13887.5 Barrer/cm, and the minimum oxygen permeability is 24.1×10 ⁻⁹ (cm×mlO ₂ )/(sec×ml×mmHg) is
contact lens.
[36]
The contact lens of [35], wherein said medium has a water permeability coefficient of less than 20,000 Barrer.
[37]
The contact lens of [35], wherein said medium has an oxygen permeability coefficient greater than 200 Barrer.
[38]
an area of the medium measuring more than 50 square millimeters of said contact lens has a thickness of the medium that provides a water permeability lower than a maximum while providing an oxygen permeability higher than the minimum [35] The contact lens described in .
[39]
The contact lens of [35], wherein the medium comprises a polymer containing crosslinked polydimethylsiloxane.

Claims (17)

a contact lens,
an anterior surface facing away from the eye;
a posterior side facing toward the eye, and
a medium between the front surface and the rear surface and having a permeability coefficient for oxygen and a permeability coefficient for water, the medium comprising a polymer containing crosslinked polydimethylsiloxane;
a thickness of the medium that provides a water permeability lower than the maximum while providing an oxygen permeability higher than the minimum;
wherein the maximum value of the water permeability is 13887.5 Barrer/cm, and the minimum value of the oxygen permeability is 24.1×10 ⁻⁹ (cm×mlO ₂ )/(sec×ml×mmHg) is
contact lens. 2. A contact lens according to claim 1, wherein the medium has a water permeability coefficient of less than 20,000 Barrer. 2. A contact lens according to claim 1, wherein the medium has an oxygen permeability coefficient greater than 200 Barrer. 2. The contact lens of claim 1, wherein an area of the medium measuring more than 50 square millimeters has a thickness of the medium that provides a water permeability lower than a maximum while providing an oxygen permeability higher than a minimum. The contact lens described in . A contact lens according to claim 1, wherein said medium thickness has an average thickness of at least 0.2 millimeters. A contact lens according to claim 1, wherein said medium thickness has an average thickness of at least 0.3 millimeters. A contact lens according to claim 1, wherein said medium thickness has an average thickness of 0.29 millimeters. a contact lens,
comprising a medium having a permeability coefficient for oxygen, a permeability coefficient for water, and a thickness;
The thickness of the medium has an average thickness of at least 0.2 millimeters, thereby providing a water permeability of less than 13887.5 Barrers/cm and a water permeability of 24.1×10 ⁻⁹ (cm×mlO ₂ )/( sec × ml × mmHg) is obtained,
the medium has a water permeability coefficient of less than 20,000 Barrer;
the medium has a permeability coefficient for oxygen greater than 200 Barrer;
contact lens. 9. A contact lens according to claim 8, wherein the medium comprises a layer of polymer containing crosslinked polydimethylsiloxane. 9. A contact lens according to claim 8, wherein said medium consists of a single lens material made of crosslinked polydimethylsiloxane. 9. A contact lens according to claim 8, wherein said media thickness has an average thickness of at least 0.3 millimeters. 9. A contact lens according to Claim 8, wherein the medium thickness has an average thickness of 0.29 millimeters. a contact lens,
comprising a medium having a permeability coefficient for oxygen, a permeability coefficient for water, and a thickness;
The thickness of the medium has an average thickness of at least 0.2 millimeters, thereby providing a water permeability of less than 13887.5 Barrers/cm and a water permeability of 24.1×10 ⁻⁹ (cm×mlO ₂ )/( sec x ml x mmHg),
contact lens. 14. A contact lens according to claim 13, wherein the medium has a water permeability coefficient of less than 20,000 Barrers and an oxygen permeability coefficient of greater than 200 Barrers. 14. A contact lens according to claim 13, wherein said medium consists of a single lens material made of crosslinked polydimethylsiloxane. 14. A contact lens according to claim 13, wherein the medium thickness has an average thickness of at least 0.3 millimeters. 14. A contact lens according to Claim 13, wherein the medium thickness has an average thickness of 0.29 millimeters.

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