Patent Application
20070089998
This invention relates to packages for storing contact lenses. In particular, the invention provides a contact lens package that facilitates removal of the lens from the package.
Contact lenses have been used to improve vision for many years. Contact lenses originally were made of hard materials, which were relatively easy to handle, but were uncomfortable on-eye for many patients. More recently, softer lenses made of hydrogels, including silicone hydrogels, have been commercialized, which lenses are more comfortable to wear.
Most contact lenses, in particular soft contact lenses, typically are packaged in individual blister packages having a bowl portion and a foil top. The more pliable the lenses, the more problems that are presented to the user in removing the lenses from the package. For example, the soft contact lenses may be difficult to grasp and extract from the package or the lens may fold on itself when extracted.
The invention provides contact lens packages, and methods of using and making such packages, that facilitate removal of the lens from the packages. In the packages of the invention, removal of the lens is facilitated by providing a package which elevates the lens when the package is opened. The invention is useful with any type of contact lens, but may find its greatest utility with soft contact lenses.
In one embodiment the invention provides a contact lens package comprising, consisting essentially of, and consisting of a means for elevating a contact lens stored therein.
Typically, soft contact lenses are purchased by the consumer in blister packages. A blister package is a small, bowl-shaped, fluid-filled package the top of which is sealed with a laminated foil top. When the conventional blister package is opened, the lens remains in the bottom of the fluid-filled cavity that typically is bowl-shaped.
In
It is a discovery of the invention that removal of the lens from a package can be facilitated by providing a means for elevating the lens when the package is opened. The lens may be elevated any amount of height, but preferably is elevated so that it is above the surface of the lens storage solution within the package. More preferably, the lens is elevated above the top edges of the cavity in which the lens has been packaged.
The elevation means may be any means suitable for elevating the contact lens to the desired height. Thus, the elevating means may be, without limitation, a mechanical deformation of the storage cavity within the package when the package is opened which deformation results in elevation of the lens, a spring, a lever, a sponge, a foam or other means that is activated on opening of the package to elevate the lens and combinations thereof. In the packages of the invention, preferably, the elevating means is a mechanical deformation of the package or a foam that, when wetted on package opening, expands and elevates the lens to the desired height.
In
The base and cover of the package may be made from any of a number of materials provided that those materials are compatible with the inspection and sterilization requirements of contact lens manufacture. Examples of suitable materials include but are not limited to polypropylene, polyethylene, nylons, olefin co-polymers, acrylics, rubbers, urethanes, polycarbonates, or fluorocarbons. The preferred materials are metallocenes polymers and co-polymers made of polypropylene, polyethylene, having a melt flow range of about 15 g/10 minutes to about 44 g/10 minutes as determined by ASTM D-1238. The base and cover may be made by any of convenient means and preferably are made by injection molding.
In
The foam useful in this embodiment may be any foam that is capable of expansion upon wetting with lens storage solution. Additionally, the foam selected must not introduce contaminants into the lens package and must be able to withstand the sterilization process for the contact lens and package. A suitable foam useful in the invention is an open cell polymer foam as for example one made from hydroxylated polyvinyl acetate. One such type of foam is commercially available under the name MEROCEL®. The amount of foam used will depend upon the size of the cavities in the package within which the lens and foam reside. An amount of foam is used that, upon wetting with the storage solution, expands sufficiently so as to elevate the contact lens to a desired height, preferably to elevate the lens above the height of the cavity in which the lens resides.
The materials useful for forming the cover and base of this embodiment of the package are the same as for those of the first embodiment. However, in this package, it is not preferred that the cover or the ring material be made of a higher modulus material than the base.
The packages of the invention preferably are used to store contact lenses made from silicone elastomers or hydrogels, which include but are not limited to silicone hydrogels, and fluorohydrogels. Soft contact lens formulations are disclosed in U.S. Pat. No. 5,710,302, WO 9421698, EP 406161, JP 2000016905, U.S. Pat. No. 5,998,498, U.S. patent application Ser. No. 09/532,943, U.S. Pat. No. 6,087,415, U.S. Pat. No. 5,760,100, U.S. Pat. No. 5,776,999, U.S. Pat. No. 5,789,461, U.S. Pat. No. 5,849,811, and U.S. Pat. No. 5,965,631. The foregoing references are hereby incorporated by reference in their entirety. More preferably, the packages are sued to store soft contact lenses made from etafilcon A, genfilcon A, lenefilcon A, polymacon, acquafilcon A, balafilcon A, lotrafilcon A. and silicone hydrogels as prepared in U.S. Pat. No. 5,998,498, U.S. patent application Ser. No. 09/532,943, a continuation-in-part of U.S. patent application Ser. No. 09/532,943, filed on Aug. 30, 2000, U.S. Pat. No. 6,087,415, U.S. Pat. No. 5,760,100, U.S. Pat. No. 5,776,999, U.S. Pat. No. 5,789,461, U.S. Pat. No. 5,849,811, and U.S. Pat. No. 5,965,631 hereby incorporated by reference in their entirety.
