Note: Descriptions are shown in the official language in which they were submitted.
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Package for Hydrophilic
_ Contact Lens
Field of Invention
This invention relates to blister packages. and more
particularly, to a blist~r package for storing and
dispensing hydrophilic contact lenses which are maintained
in an aqueous solu~ion.
Backqround of the Invention
Soft, hydrophilic contact lenses are manufactured from
hydrophilic polymeric materials such as copolymers of
hydroxyethyl methacrylate, and may contain from ~0 to 90
percent or more water, depending on polymer composition.
Such lenses must be ~tored in a sterile aqueous solution,
usually isotonic saline, to prevent dehydration and to
maintain the lenses in a ready to wear condition.
Common practice has been for lens manufactur2rs to use
a stoppered glass bottles as the storage and shipping
container for each individual lens. The standard contact
lens bottle is approximately lOcc in volume, is sealed
with a silicone stopper and provided with a metal foil
overcap safety seal. ~.ach bottle contains approximately
7cc of saline and a single contact lens which is
identified on the label of the bottle. When the lsns is
to be removed for fitting on a patient, the practitioner
must first tear and remove the metal safety seal, then
remove the ~topper, and finally remove the lens with a
plastic tweezer.
Packaging contact lenses in glass bottlss is expensive
due to the cost of bottles, stoppers and seals, and
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shipping i6 expensive due to the weight of the glass and
saline. Bottles are also 6ubject to breakage if
accidentally dropped during handling, and removing the
lens from the bottle with tweezers is inconvenient since
the lens i5 nearly invisible when submerged in saline.
It is accordingly an object of the present invention
to provide an improved package for 6toring, shipping and
dispensing hydrophilic contact lenses. It i8 a further
object of this invention to provide a lens package which
allows for improved efficiencies in the len~ manufacturing
process. It is a yet further object of this invention to
provide an inexpensive package which allows for convenient
removal of the contact lens. These and other objects of
this invention will be apparent from the ensuing
description and claims.
Summarv of Invention
The package of the present invention i~ a shaped
blister package covered with a flexible sheet material
which can be 6tripped from the package to gain access to
the lens. The molded base or blister portion of the
package includes a cavity for receiving the contact lens
and saline solution, and an outward extending flange
around the perimeter of the cavity to which the cover
material is sealed. The cavity of the package is defined
by a bottom surface and ~ide walls extending between the
bottom surface and the peripheral ~lange. A portion of
the side wall is inclined away from the bottom surface to
form a ramp or inclined surface between the bottom of the
cavity and the flange. The co~er material is sealed to
the flange around the cavity by ~eans which allow the
cover to be readily stripped or peeled from the flange.
The flange adjacent the inclined surface and the overlying
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cover material extend outward beyond the seal area to
provide unsealed edges which may be gripped to facilitate
removal of the cover.
The package according to the present invention is
inexpensive, light in weight. and requires le~s saline for
lens storage. The package is conveniently opened by
stripping the cover from the flange to expose the cavity
and the lens in a shallow bath of saline. The lens is
conveniently removed by sliding the lens up the inclined
surface using either tweezers or a finger.
The base portion of the package may be injection
molded or thermoformed from any suitable thermoplas~ic
sheet material such as polypropylene. The cover stock may
be a laminate of polypropylene film and aluminum foil
whi~h can be heat sealed to the flange around the cavity
of the package. Lens identification and other label
information can be printed on the cover stock. Once the
package is opened and sterility lost, the package is not
amenable to reclosure.
According to a still further broad aspect of the present
invention there is provided a package for a hydrophilic
contact lens maintained in a sterile aqueous solution. The
package comprises a molded base having a cavity for contain-
ing the contact lens and a flange extending outwardly about
the periphery of the cavity. The cavity is defined by a
bottom surface and side wall surfaces extending between the
bottom surface and the flange. A portion of the side wall
surface is inclined away from the bottom surface at an angle
from about 130 to 160 degrees. ~he inclined side wall
surface forms a ramp between the bottom of the cavity and
the flange. A flexible cover sheet is releasably sealed to
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the flange around the perimeter oE the cavity. The cover
sheet and the flange adjacent the edge of the inclined side
wall surface extends outwardly to beyond the area of the
seal. The unsealed edges of the cover shee-t and the flange
comprise gripping means for separating the cover sheet from
the flange to expose the inclined side wall and the cavity.
The package is impermeable to bacteria to preserve sterility
and has a negligible moisture vapor transmission rate to
avoid loss of water. The pac~age is also sterilizable.
Description of Drawinqs
Fig. 1 is a phantom view in perspective of a package
according
to the present invention.
Fig. 2 is a perspective view of the package of Fig. 1
with
the cover partially removed.
~ig. 3 is a side elevational plan view of the package of
Fig. 1.
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Fig. 4 is a top plan view of the package of Fig. 1 with
the cover removed.
Fig. 5 is a top plan view of another embodiment of a
package
according to the present invention with the cover
removed.
Fig. 6 is a top plan view of another embodiment of a
ackage according to the present invention with
the cover removed.
i
Fig. 7 is a side elevational view of the package of Fig.
DescriPtion of Embodiments
With reference to Fig. 1, there is illustrated a
preferred embodiment of a package according to the present
invention consi6ting of lower base portion 11 and cover
member 12. The lower portion includes a cavity indicated
generally a6 13 which is formed by inclined side wall 14
and upstanding 6ide wall~ 15. The cavity is ~urrounded by
outward extending flange 16. Cover 12 is ~ealed to flange
16 around the opening of cavity 13 as indicated by seal
line 17. Cavity 13 i~ sized to receive contact lens 19
and a sufficient quantity of saline 20 to completely
submerge the lens.
As illustrated in Fig. 1, that portion of flange 16
and cover 12 adjacent inclined side wall 14 e~tends well
beyond the area of seal 17. The unsealed edges of the
flange and cover thereby provide gripping means whereby
the cover may be readily stripped from the flange to gain
acces6 to cavity 13 and the lens contained therein. An
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opened package with the cover member still secured along
the rear edge of the flange is illustrated in Fig. 2. The
seal line between inclined 6ide wall 14 and the unsealed
edges of the cover and flange is preferably chevron shaped
as illustrated in Fig. 1 and ;2 for ease in opening the
package since the chevron configuration allows for a more
uniform stripping force to be applied, assuring that the
package can be opened without spilling the contents.
Fig. 3 is a side plan view which most clearly
illustrates the slope of inclined ~urface 14. Preferably,
surface 1~ should form an obtuse angle of from about 130
to 160 degrees with the plane of the bottom surface of
cavity 13, and most preferably from about 140 to 150
degrees. A ~lope within this range allows the lens to be
readily removed from the cavity without unduly increasing
the volumn of the cavity or the length of the seal line
around the perimeter of the cavity. A typical contact
lens has a diameter of from about 13 to 15 mm and a depth
of from about 3 to 4 mm. A suitable cavity for such a
lens is from 6 to 10 mm deep with a 20x20 mm bottom
surface and an opening of about 20x30 mm. The outer
dimension of such a package i~ approximately 3x6 cm.
Fig. ~ is a top plan view of the package of Fig. 1
with cover 12 removed to more clearly illustrAte the
configuration of cavity 13. Fig. 5 is a top plan view of
another embodiment of a package wherein cavity 2~
surronded by ~lange 26 i6 defined by semicircular
upstanding side wall 25 merging into inclined side wall
34. Fig. ~ illustrates a further embodiment of the
present invention wherein the bottom surface 38 of cavity
33 is concave. The concave surface encourages the lens
contained in the cavity to rest on the bottom surface with
the edges of lens extending upward, thereby increasing the
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ease with which the lens may be located and brought up to
flange 36 oE the package. The inclined sidewall surface
~ may likewi6e be flat or concave as desired.
The lower portion 12 of the package according to the
present invention is preferably produced by thermoforming
polypropylene sheet material having a thickness of about
0.8 mm. Polypropylene is preferred for its good
thermoforming properties, its ability to withstand heat
sterilization at about 120C. with little or no 6hrinkage
or distortion, and it6 ability to be heat 6ealed to cover
stock material.
The cover stock is preferably an adhesive laminate of
aluminum foil and polypropylene film which can be heat
sealed to the base section of the package to provide an
air tight seal, and yet be readily stripped from the
package when the package is ~o be opened. The aluminum
foil is preferably coated or lacquered on the opposite
surface to provide label identification and a receptive
6urface for later imprinting lens parameters such as
diameter, power, and base curve.
The packages of the present invention may be
constructed of materials other than those identified
herein although materials as identified provide good
result6. Packages constructed of materials 6uch as
polyethylene which are less heat resistant than
polypropylene and not 6uitable for heat 6terilization may
- 30 be radiation or gas ~terilized, optionally with aseptic
assembly techniques.
In addition ~o wi~hstanding ~terilization temperature6
of about 120~C., the sealed packages for hydrophilic
contact lenses must be impermeable to bacteria to preserve
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sterility, have a negligible moisture vapor transmis6ion
rate to avoid 1066 of water, and be able to maintain the
lens in its original condition for the stated shelf life
of the product, usually 2 to 4 years. The package
materials and the packaging procedures must be selected
accordingly.
While the packages of the present invention as
illustrated herein have been yenerally rectangular in
shape with a rectangular or elongated cavity, it will be
apparent ~hat many other sizes and shapes may be utilized
without departing from the scope of the present
invention. The packages of the present invention are
characterized by a storage cavity having an inclined wall
or ramp extending from the bottom of the cavity to a
peripheral outstanding flange, and a removable cover sheet
sealed to said flange around the perimeter of said
cavity. Materials, methods of fabrication and package
configuration may vary according to the specific needs and
desires of the practicioner.
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