Ophthalmic lenses and compositions, and methods for...

Details Ophthalmic lenses and compositions, and methods for... Ophthalmic lenses and compositions, and methods for...

2000-04-18

2002-04-16

Seidleck, James J. (Department: 1711)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Processes of preparing a desired or intentional composition...

C526S320000, C526S331000, C526S327000, C526S318420, C264S002600

Reexamination Certificate

active

06372815

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to ophthalmic lenses, compositions useful for inclusion in such lenses, and methods for producing such lenses and compositions. More particularly, the invention relates to polymeric ophthalmic lenses, such as corneal contact lenses and the like, polymeric compositions useful included in ophthalmic lenses and methods for producing such lenses and compositions.
Hydrophilic lenses, such as corneal contact lenses, are often formed from covalently cross-linked polymers based on hydrophilic derivatives of acrylic or methacrylic acid, hydrophilic vinylic monomers such as vinylpyrrolidone, and the like. When hydrated, these hydrophilic cross-linked polymers can be referred to as hydrogels and include relatively large quantities of water without dissolving. Such polymers may include minor amounts of polymeric units derived from less hydrophilic, or even hydrophobic, monomers to confer mechanical strength and other useful properties.
Although conventional hydrophilic polymer or hydrogel lenses are useful and effective, some problems do present themselves, from time to time. For example, conventional hydrophilic contact lenses, particularly after long periods of in-the-eye use, do have a tendency to lose water content. Reduction in water content tends to detrimentally affect the physical structure and/or optical properties of the lens. This reduction in water content can lead to lens wearer discomfort and even to actual irritation or other damage to the eye. In addition, such conventional lenses may lose lubricity or exhibit relatively large amounts of friction with the corneal surface, which also can cause lens wearer discomfort and/or eye irritation and the like. Such reduced lens water content and/or reduced lubricity can result in the lens wearer perceiving that his/her eye is dry. Such “dry eye” phenomenon can be overcome through the use of eye drops and/or lubricants. However, it would be advantageous to reduce or even substantially eliminate these problems without the need for eye drops or separate lubricants.
In short, there is a continued need for enhanced ophthalmic lenses, e.g., corneal contact lenses, enhanced materials of construction for such lenses and enhanced methods for producing such lenses and materials.
SUMMARY OF THE INVENTION
New ophthalmic lenses, such as corneal contact lenses, polymeric compositions useful for inclusion in such ophthalmic lenses, and methods for producing such lenses and polymeric compositions have been discovered. The present invention provides substantial benefits in terms of reducing discomfort and/or irritation to the wearer of the present lenses as a result of wearing such lenses, for example, relative to wearing a conventional lens. The present lenses, which include the present compositions, preferably provide for increased water content and/or increased water retention and/or reduced surface evaporation of water. The present contact lenses exhibit reduced friction toward hydrophilic surfaces such as the cornea. Further, such lenses have effective, and even enhanced, modulus, and structural and optical stability, for example, relative to conventional lenses. A lens wearer can often wear the present lenses effectively for relatively longer periods of time and/or with reduced or no harmful effects relative to conventional lenses.
The present methods for producing polymeric compositions and lenses are relatively straightforward to practice and provide compositions and lenses which have controlled characteristics useful in producing substantial benefits, for example, one or more the benefits of the present lenses described herein.
In one broad aspect, the present invention is directed to ophthalmic lenses comprising lens bodies. Such lens bodies comprise compositions including a first polymer material, preferably a first cross-linked polymer material, which is water swellable; and a second polymeric material, other than the first material, selected from water soluble polymeric materials, water swellable polymeric materials and mixtures thereof. The second material is immobilized, preferably physically immobilized, by the first material. In one embodiment, for example, with the second material being a water soluble material, the composition included in the present lenses preferably may be considered a pseudo-interpenetrating network. With the second material selected from water swellable materials, the composition in the lenses preferably may be considered a true interpenetrating network of the first material and the second material.
Without wishing to limit the invention to any particular theory of operation, it is believed that such structures of the combinations of first materials and second materials in accordance with the present invention provide the effective and surprising properties and benefits to the present lenses.
The first material and the second material are chosen or selected to provide one or more desired properties, for example, lenses with one or more desired properties which provide one or more benefits to the lenses and/or the lens wearers.
Advantageously, the lens bodies in accordance with the present invention, when hydrated, exhibit one or more of the following beneficial characteristics or properties:
increased water retention relative to a substantially identical lens body without the second material;
increased equilibrium water content relative to a substantially identical lens body without the second material;
reduced surface evaporation of water relative to a substantially identical lens body without the second material;
increased modulus or tensile strength relative to a substantially identical lens body without the second material; and
a reduced coefficient of friction relative to a substantially identical lens body without the second material.
Lenses, such as contact lenses, which include and/or retain increased amounts of water are effective in providing increased lens wearer comfort and/or reducing the risk of irritation and/or other damage to the eye of the lens wearer. Reducing the friction between the lens and the eye, for example, the cornea of the eye, such as by maintaining an increasing water content and/or reducing coefficient of friction, also increases comfort and reduces risk of irritation. Lenses with increased modulus or tensile strength have longer useful lives and/or can be made more thin to enhance lens wearer comfort. In addition, lenses with such reduced coefficients of friction are able to be worn without the lens wearer perceiving excessive eye dryness. The present lenses often have what may be termed a slippery or lubricious feel, for example, because of the increased water content and/or the reduced coefficient of friction. In addition, by selecting suitable monomers from which the first material and the second material are made, the present lenses can advantageously have a reduced tendency to accumulate proteinaceous and other deposit material.
In another broad aspect of the present invention, methods for producing ophthalmic lenses. In general, such methods comprise:
providing a lens body comprising a lens composition including a first polymer material, preferably a first crosslinked polymer material, which is water swellable;
introducing a monomeric component into the lens body, the monomeric component preferably being soluble in at least one member selected from the group consisting of water, water miscible solvents and mixtures thereof; and
subjecting the monomeric component in the lens body to effective conditions, for example, effective polymerization conditions, to form a second polymeric material selected from water soluble polymeric materials, water swellable polymeric materials and mixtures thereof. The second material is immobilized, preferably physically immobilized, by the first material.
In one embodiment, the monomeric component is substantially free of a cross-linker. Alternately, the monomeric component may include an effective amount of a cross-linker.
In addition, the monomeric component may include an amount of

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