Optics: eye examining – vision testing and correcting – Spectacles and eyeglasses – Ophthalmic lenses or blanks
Reexamination Certificate
2003-04-15
2004-11-02
Schwartz, Jordan M. (Department: 2873)
Optics: eye examining, vision testing and correcting
Spectacles and eyeglasses
Ophthalmic lenses or blanks
C351S165000
Reexamination Certificate
active
06811257
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to corrective eyewear that is designed to be placed directly on the eye and is commonly known as contacts. Furthermore the present invention relates to contact lens eyewear that filters ultraviolet light, blue light and polarized light.
2. Description of the Prior Art
One of the most common forms of corrective eyewear on the market is contact lenses. These lenses are very small discs that are worn directly on the eye and cover at least the pupil. The common cause for poor vision is that the eye is unable to focus all of the incoming light correctly to the retina located at the rear portion of the eyeball. This leads to blurring of vision. Contacts, like other corrective eyewear, refocus light before it enters the pupil so that the retinal image will no longer be blurred. The material that is used to make the contact lenses is of a different index of refraction then the air. This causes the path of light that enters the material to be bent. Contacts are carefully constructed to bend light according to preset specific degrees by varying the curvature of the convex outer surface, the concave inner surface and the thickness between these surfaces. Through an examination process the level of refocusing that is required for a particular wearer is determined and the wearer is then matched with contacts constructed appropriately. There are several materials that have been used for constructing contacts such as glass, and various types of polymers.
The benefits of reducing the level of ultraviolet light entering the pupil are well known. Firstly, unfiltered ultraviolet light can be very harsh and cause discomfort. Secondly, there is evidence that it can lead to permanent damage such as cataracts. For example the number of cases of this condition is larger in the southern portion of the United States where the sunny climate leads to greater exposure to ultraviolet light. Therefore it can be seen that it would be beneficial to provide a filter in contact lenses that would reduce the level of ultraviolet light entering the pupil. This filtering process should only occur when necessary or else the wearer would not be able to see well indoors or at night. There are several materials that are known in the prior art that change their chemical alignment as the level of ultraviolet light increases. These photochromic materials will increase the level of filtering as the level of ultraviolet light increases. Conversely, as the ultraviolet light decreases the chemical alignment will return to its previous form and filter less. It is also known that polymers may be immersed in photochromic materials to saturate them. The resulting polymeric materials act as photosensitive filter to ultraviolet light.
Another filtering feature that is beneficial in eyewear is the reduction of polarized light. Sunlight comprises transverse waves in all directions. When it reflects off of materials such as water, sunlight realigns into predominately horizontal transverse waves. This leads to perceived images of glare and blurriness that is extremely uncomfortable. Therefore several materials have been developed that filter out light at particular orientations to reduce the harshness of this effect. These materials comprise molecules that align themselves in a linear fashion and filter out light accordingly. Since the benefits of filtering polarized light is well known it is clear that it would be beneficial to provide such a filter on contact lenses.
Experiments have indicated that blue light can cause alterations to the photochemistry of the retina that may be detrimental. Furthermore the reduction of blue light can improve vision in atmospheric haze and improve contrast in darker lighting. Another benefit of filtering blue light is a reduction in chromatic irregularity. This leads to improved sharpness. Someone who puts on a pair of blue attenuating lenses can immediately identify these abovementioned benefits. Therefore it would be beneficial to provide a blue light filter on contact lenses.
U.S. Pat. No. 4,377,329 to Stanley Poler discloses a design for a contact lens that comprises a central element that covers the maximum area of the pupil and acts as the vision-correcting element. The remainder of the device is a haptic that is designed for application and wear while minimizing the coverage of the eyeball of the wearer. The present invention suggests a central pupil-covering element, but additionally discloses an element of this type that comprises a photochromic material. The Poler '329 patent Does not disclose a filter for polarized light or blue light.
U.S. Pat. No. 4,681,412 to Jerome H. Lemelson is a design for a contact lens that contains light sensitive material. Several versions of lenses with this property are suggested. The version that is closest to the present invention is pictured in FIG. 1. This design comprises a photosensitive material that encompasses the central portion of the contact and is molded to a non-photosensitive material at the outer rim. While the Lemelson '412 patent discloses a structure for filtering ultraviolet light that is similar to the present invention, there is no disclosure in this patent for a filter for polarized light or blue light.
U.S. Pat. No. 4,889,413 to Mary E. Ormsby et al discloses a manufacturing process for producing polyurethane plastics that have photochromic properties. While this patent discloses photochromic materials, it does not disclose the use of such a material for contact lenses. Furthermore it does not suggest the use of a polarizing filter or a blue light filter in coordination with such a material.
U.S. Pat. No. 5,181,053 to Howard J. Brown describes a tool for forming a contact lens into multi-focal lenses. While this patent does describe a method for producing a separate element at the diameter of a pupil, it does not disclose the incorporation of photochromic or photosensitive material. The Brown '053 patent docs not disclose a filter for polarized light or blue light
U.S. Pat. No. 6,113,813 to Kamal Goudjil discloses a photochromic ultraviolet protective shield. While this disclosure does disclose a device that incorporates a photochromic material, it does not disclose the use of such a material in contact lenses. Additionally, the Goudjil '813 patent does not disclose a filter for polarized light or blue light.
U.S. Pat. No. 6,248,264 to Clark et al is a patent for compositions that comprise a compound that has photochromic properties. While this is an example of the many materials that provide photochromic properties, the materials themselves are not being claimed here. The disclosure of the present invention is the use of such a composition in a contact lens in coordination with a filter for polarized light or blue light.
Therefore a need exists for a novel and enhanced contact lens that provides a filtering element for polarized light. Photochromic material may also be incorporated into the contact lens to filter ultraviolet light.
SUMMARY OF THE INVENTION
In view of the foregoing disadvantages inherent in the known types of contacts present in the prior art, the present invention provides an improved combination of comfort and well being, and overcomes the abovementioned disadvantages and drawbacks of the prior art. As such, the general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new contact lens which has all of the advantages of the prior art mentioned heretofore and many novel features that result in a contact lens which is not anticipated, rendered obvious, suggested, or even implied by the prior art, either alone or in combination thereof.
In furtherance of this objective, the contact lens including elements for filtering ultraviolet light, blue light, and polarized light comprises a contact lens that comprises material that filters polarized light.
There has been outlined, rather broadly, the more important features of the invention in order that the detailed descri
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