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  Ophthalmic devices having a highly selective violet light transmissive filter and related methodsUSPTO Application #: 20080013045Title: Ophthalmic devices having a highly selective violet light transmissive filter and related methods Abstract: Ophthalmic devices are provided having a violet-light vertical cut-off filter abruptly absorbs light between the wave lengths of between approximately and 400 nm and 450 nm such that a curve when plotted as percent transmission versus wavelength has the shape as depicted in FIG. 2. In one embodiment the ophthalmic devices are made from acrylates and the light absorbing compound is an Eastman Yellow 035 MA dye. (end of abstract) Agent: Advanced Medical Optics, Inc. - Santa Ana, CA, US Inventors: Martin A. Mainster, Alan J. Lang, Michael D. Lowery USPTO Applicaton #: 20080013045 - Class: 351163000 (USPTO) The Patent Description & Claims data below is from USPTO Patent Application 20080013045. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS REFERENCE To RELATED APPLICATIONS [0001] This application claims the benefit of U.S. application Ser. No. 11/115,743, filed Apr. 26, 2005, which claims the benefit of U.S. Provisional Application No. 60/567,281, filed Apr. 30, 2004, which is incorporated herein by reference in its entirety. FIELD OF THE INVENTION [0002] The present invention relates to ophthalmic devices suitable for use in mammals. More specifically, the present invention relates to ophthalmic devices having at least one highly selective (abrupt) violet light transmissive filter incorporated therein. Additionally, related methods for making ophthalmic devices having highly selective violet light transmissive filters are provided. BACKGROUND OF THE INVENTION [0003] There are three primary structures within the human eye that are essential to vision and subject to age-related damage: the cornea, lens and retina. The retina is a multi-layered sensory tissue that lines the back of the eye. It contains millions of photoreceptors that capture light rays and convert them into electrical impulses. These impulses travel along the optic nerve to the brain where they are turned into images. There are two types of photoreceptors in the retina: rods and cones. The retina contains approximately 6 million cones. The cones are contained in the macula, the portion of the retina responsible for central vision. They are most densely packed within the fovea, the very center portion of the macula. Cones function best in bright light and allow us to appreciate color. There are approximately 125 million rods. They are spread throughout the peripheral retina and function best in dim lighting. The rods are responsible for peripheral and night vision. The retina is essential for vision and is easily damaged by prolonged unprotected exposure to visible and near visible light. Light-induced retinal pathologies include cystoid macular oedema, solar retinopathy, ocular melanomas and age-related macular degeneration (ARMD). Light-induced retinal damage is classified as structural, thermal or photochemical and is largely determined by the exposure time, power level and wavelength of light (W. T. Ham. 1983. Journal of Occupational Medicine. 25:2 101-102). [0004] In healthy adults the retina is generally protected from the most severe forms of light-induced damage by the outer eye structures including the cornea and crystalline lens. The cornea is a transparent proteinaceous ocular tissue located before the iris and is the only eye structure exposed directly to the environment. The cornea is essential for protecting the delicate internal structures from damage and facilities the transmission of light through the aqueous media to the crystalline lens. The cornea is the primary light filter and therefore is particularly susceptible to excessive light exposure-related damage including corneo-conjunctival diseases such as pterygium, droplet climatic keratopathy and pinguecula. In the healthy eye, the cornea, in conjunction with the aqueous medium, absorbs, or blocks, wavelengths (nm shall be used hereinafter to denote wavelengths of light in nanometers) in the short ultraviolet (UV)-B and UV-C region (less than .apprxeq.320 nm). [0005] The crystalline lens is an accommodating biological lens lying directly behind the iris and cornea and facilitates the convergence of both far and near images onto the retina. The natural crystalline lens blocks near UV radiation (UV-A) (320 nm to 400 nm) from reaching the retina. Therefore, most of the damaging UV-A, -B and -C radiation are prevented from reaching the retina in healthy people with an intact crystalline lens and cornea. Thus in the normal mammalian eye only wavelengths between about 400 nm and 1,400 nm can reach the retina. However, high transmittance levels of blue and violet light (wavelengths from about 390 nm to about 500 nm) has been linked to retinal damage, macular degeneration, retinitis pigmentosa, and night blindness. In addition, blue and violet light tends to be scattered in the atmosphere, especially in haze, fog, rain, and snow, which in part can cause glare, and diminished visual acuity. As the eye ages the crystalline lens begins to take on a yellow tint that absorbs some radiation in the blue and violet wavelength ranges, in addition to the majority of near UV radiation. Thus, the natural crystalline lens protects the eye's delicate retina from near UV light throughout life and subtly yellows with age, thereby increasing the amount of blue and violet light that is absorbed. [0006] The natural crystalline lens is also susceptible to age-related degenerative eye diseases such as cataracts. Cataract is a clouding of the crystalline lens caused by the coagulation of lens proteins within the capsular sac. Many ophthalmologists believe that cataract formation results from a lifetime of oxidative insults to the lens and is exacerbated by smoking, excessive exposure to bight light, obesity and diabetes. Cataracts develop slowly in most people and eventually reach the point where vision is substantially impaired resulting in near to total blindness. In these persons lens removal and replacement with synthetic polymer ophthalmic devices such as an intraocular lens is the preferred means for restoring normal sight. However, once the natural crystalline lens is removed the retina is left unprotected from damaging UV and short wavelength violet light. Thus early synthetic ophthalmic devices were provided with UV absorbing compounds such as benzophenones and benzotriazoles-based UV light absorbers. Moreover, many benzophenones and benzotriazoles are polymerizable and thus can be stably integrated into most modern ophthalmic device compositions including acrylates and hydrophilic hydrogel co-monomers and co-polymers. Ultraviolet light does not play a positive role in human vision. Thus ophthalmic devices having UV absorbing dye concentrations that block virtually all UV light became common-place by the mid 1980s. [0007] In the 1990s ophthalmic devices having violet light absorbing materials such as azo dyes incorporated therein were introduced to approximate the violet light blocking effects of the aging adult natural crystalline lens. For example, U.S. Pat. No. 4,390,676, describes polymethylmethacrylate (PMMA) polymer ophthalmic devices incorporating yellow dyes that selectively absorb UV, violet and blue light radiation up to approximately 450 nm. U.S. Pat. Nos. 5,528,322; 5,543,504; and 5,662,707 are assigned to Alcon Laboratories, Inc. and disclose acrylic-functionalized yellow azo dyes having an inert chemical spacer between the dye and acrylic portions of the molecule. Thus the violet light-absorbing portion of the molecule is protected from undesirable color shifts when polymerized with the lens polymer. Moreover, because the dye is acrylic-functionalized, it is polymerizable with the lens polymer and thus stably incorporated into the ophthalmic device polymer matrix. Similarly, Menicon Co., Ltd. holds U.S. Pat. Nos. 6,277,940 and 6,326,448 both disclosing specific acrylic-modified azo dyes structurally similar to Alcon's. Hoya Corporation owns U.S. Pat. No. 5,374,663 that discloses non-covalently linked yellow dyes including solvent yellow numbers 16, 29 and others incorporated into a PMMA matrix. Moreover, Hoya also owns U.S. Pat. No. 6,310,215 that discloses acrylic-functionalized pyrazolone dyes suitable for use in acrylic and silicone ophthalmic devices. [0008] However, these and other prior art ophthalmic devices have the violet blocking dyes evenly distributed throughout the ophthalmic device material at concentrations that simulate the natural yellow color of the 53 year-old individual's crystalline lens. Consequently, all light and images are filtered through a yellow color before being projected on the retina. For activities that rely on acute photopic sensitivity (day light visual conditions) this may be desirable. For example, people who engage in certain day time outdoor sports or activities including skiers, baseball players, football players, pilots, and boaters are exposed to high levels of ultraviolet, violet, and visible light radiation which can affect visual acuity required in such activities. Drivers of motor vehicles also have specific needs in terms of reducing glare and enhancing visual acuity under bright, sunlit driving conditions and reducing headlight glare at night. [0009] However, unlike UV radiation, the violet light spectrum (440 nm to about 500 nm) are important for maintaining optimal visual acuity, especially scotopic (night) vision. Thus ophthalmic devices containing dyes that block significant amounts of violet light over the majority of the violet light spectrum can adversely affect scotopic vision. This is an especially acute problem in older adults that naturally suffer declining scotopic vision and reduced pupil dilation. Consequently, an ophthalmic device is needed that balances the need for reducing the possible damaging effects of blue and violet light exposure against the need to maintain good scotopic vision. [0010] Therefore, it is an objective of the present invention to provide an ophthalmic device having a highly selective (abrupt) violet light transmissive filter incorporated therein that protects against radiation in the violet waveband and more damaging portions of the blue waveband, thus providing improved scotopic vision when compared to prior art devices. SUMMARY OF THE INVENTION [0011] The present invention achieves this and other objectives by providing an ophthalmic device having a violet light absorbing dye that selectively filters wavelengths between approximately 400 nm to about 450 nm with little or no absorption of wavelengths above 450 nm (referred to herein after as a "violet-light vertical cut-off filter"). [0012] The ophthalmic devices of the present invention may be composed of any biocompatible polymer suitable for use in forming an ophthalmic device. For example, but not limited to, poly(methylmethacrylate) (PMMA). Additional polymers may be used when made using monomers selected from the non-limiting group consisting of phenylethylacrylate (PEA), phenylethylmethacrylate (PEMA), methylphenylacrylates, methylphenylmethacrylates, 2-hydroxyethyl methacrylate (HEMA). Moreover, heterocyclic N-vinyl compounds containing a carbonyl functionality adjacent to the nitrogen in the ring, and particular N-vinyl lactams such as N-vinyl pryrolidone are also suitable for use in accordance with the teachings of the present invention. Moreover, the ophthalmic devices of the present invention may also be cross-linked using di- or multi-functional monomers and in small amounts as is well known in the art. Representative crosslinking agents include ethylene glycol dimethacrylate, triethylene, glycol dimethacrylate and trimethylolpropane trimethacrylate. The cross linking agents are typically dimethacrylates or diacrylates, although dimethacrylamides are also known. [0013] The light absorbing dye used to form the violet-light vertical cut-off filter may be any dye capable of absorbing light between approximately 400 nm to about 450 nm. Exemplary light absorbing dyes include, but not limited to, dyes available from Eastman Chemical such as, but not limited to, Eastman Yellow 035-MA. This dye is a methine class dye and is easily provided with a polymerizable methacrylate group. The absorption spectrum for Yellow 035-MA is provided in FIG. 3. This dye is particularly beneficial because it is a reactive dye that can be chemically bonded to the ophthalmic device polymer so that the lens is colorfast and the dye is non-extractable (i.e. will not bleed or leach out of the lens). However, it is not essential that the dye be polymerizable or capable of bonding to the ophthalmic device polymer. For example, other dyes may also be used in accordance with the teachings of the present invention capable of absorbing the desired wavelength of light. [0014] Other embodiments of the present invention include lenses having additional light absorbing dyes, specifically dyes that absorb light in the ultraviolet region, for example, but not limited to benzophenones and benzotriazoles. In yet other embodiments, the ophthalmic device is a filter only and does not itself have any significant optical power. [0015] In another embodiment of the present invention an ophthalmic device is a lens suitable for implantation into the eye of a mammal such as an intraocular lens or corneal implant wherein the lens comprises a violet-light vertical cut-off filter, and wherein the violet-light vertical cut-off filter may be distributed throughout substantially the entire ophthalmic device or may be distributed through less than the entire ophthalmic device (see FIG. 6). In the latter embodiment of the present invention, the ophthalmic device has a defined region that comprises at least one light absorbing dye, specifically dyes that absorb visible light in the wavelengths between approximately 400 nm and 450 nm. This embodiment is more fully described in co-pending U.S. utility patent application Ser. No. 11/027,876, filed Dec. 29, 2004, which is incorporated herein by reference in its entirety and which claims priority to provisional application Ser. No. 60/533,623, filed Dec. 30, 2003. [0016] The ophthalmic devices made in accordance with the teachings of the present invention include, without limitation, intraocular lenses, corneal implants, sun glasses, spectacles and contact lenses. [0017] Thus, the present invention provides an ophthalmic device that affords enhanced retina protection in high intensity lighting conditions when protection is needed most, while permitting a fuller spectrum of light to reach the retina in subdued, or low light conditions thus enhancing visual acuity and color perception. BRIEF DESCRIPTION OF THE FIGURES [0018] This patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee. [0019] FIG. 1 graphically compares the visible light transmittance curves of an aging natural crystalline lens with a lens containing UV absorbing dyes only (UV-IOL) and a lens containing UV absorbing dyes and conventional violet light absorbing dyes (Alcon Natural). The target filter area for a vertical violet light cut-off filter made in accordance with the teachings of the present invention is depicted in yellow. Continue reading... Full patent description for Ophthalmic devices having a highly selective violet light transmissive filter and related methods Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Ophthalmic devices having a highly selective violet light transmissive filter and related methods patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. 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