Contact lens packages and methods

Abstract

A contact lens package comprising: a blister package defining a cavity; a contact lens disposed within the cavity in an unstressed state; a lens moisturizing liquid partially filling the cavity; and a cover material sealed to the blister package such that a portion of the cover material is combined with the cavity to form a sealed space of the lens and the moisturizing liquid. The section has an inner surface including at least one concavo-convex element. The inner surface is flat in addition to the at least one concave-convex element. An air gap is disposed between the top surface of the liquid and at least a portion of the inner surface. At least one concavo-convex element on the inner surface of the cover material can be formed by applying pressure to the cover material using an impression having a profile corresponding to the shape of the at least one concavo-convex element when testing structural leaks.

Description

Technical Field

[0001] Apparatus and method for packaging contact lenses. Background Art

[0002] The packaging, transportation, and storage of contact lenses involve holding the contact lenses (also simply referred to herein as lenses) in the cavities of blister packs.

[0003] Typically, the lenses are initially placed in the cavities of empty blister packs. After the lenses are placed in the cavities, the packages are transported to one or more stations for further processing of the lenses and lens packages (e.g., inspection, wetting with saline or other suitable liquid, heat-sealing with a lid material (e.g., a conventional multi-layer packaging foil) into the cavities, labeling, leak testing, and sterilization (e.g., by autoclaving)).

[0004] During transportation, the lenses and packages are typically subjected to forces while moving between stations on a conveyor belt, where the lenses and packages can experience, for example, significant acceleration and deceleration, movement around curves, inversion, vibration, and / or movement of pick-and-place machines between conveyor belts.

[0005] Before heat-sealing, the movement of blister packs having lenses and a moisturizing liquid disposed in the cavities poses a quality risk, as well as a risk to the packaging machinery. For example, the movement may cause the liquid to fall on the packaging surface where the heat-seal is to be formed, or the liquid may leave the cavity onto the conveyor belt or onto the machinery at one or more stations.

[0006] After the packaging process is completed, additional quality risks are associated with the maintenance of the lenses in the packages. The lenses may remain in the packages for a significant period of time (months or years), during which the lenses are stored by the manufacturer or supplier, transported for retail, and / or stored by the consumer after retail.

[0007] During transportation and storage, the lenses may remain in various orientations within the packages. When the lens packages are held in certain orientations (e.g., upside down - the lid material is located below the lens), it is known that the interaction between the lens and the lid material (e.g., lens adhesion to the lid material by suction-cupping) can at least temporarily affect the optical properties of the lens. In some cases, after adding the moisturizing liquid and performing heat-sealing, the force exerted on the lens by air bubbles present in the cavity may exacerbate the lens adhesion. FIG. 1 is a schematic view of an upside-down contact lens package 10, where the adhesion of the lens 50 to the foil lid material 30 is affected by the force exerted on the lens by air bubbles B in the cavity C (also referred to as a "recess") of the blister pack 15. Typically, contact lens packages 10 are sold in secondary packaging (e.g., a cardboard box).

[0008] U.S. Patent No. 10,368,621 (hereinafter referred to as Barre) suggests that in order to limit the ability of a lens to fold within a lens package, the headspace (i.e., air gap) between the top of the brine and the lid material should be reduced. To reduce the headspace and the size of the bubbles generated, Barre teaches that the foil covering the package cavity is concave across the entire cavity width such that the foil protrudes into the cavity; Barre further teaches that an embossed pattern can be added to the concave foil to limit the adhesion of the lens to the foil. To further reduce the headspace and the bubble size, Barre suggests increasing the brine level in the cavity.

[0009] Ideally, the package and the packaging process maximize the yield in the process (e.g., determined by seal inspection, leak detection) and the lens performance (i.e., the lens function when the lens is worn on the wearer's eye). SUMMARY OF THE INVENTION

[0010] According to an aspect of the present invention, in a contact lens package having a lid material that seals a contact lens within a blister package cavity, the inner surface of the lid material includes at least one concave-convex element, and the inner surface of the lid material, except for the at least one concave-convex element, is flat.

[0011] As described in more detail below, the flat inner surface (except for any concave-convex elements) enhances the performance of the cushioning feature in preventing or reducing the likelihood of the lens adhering / suction-cupping to the lid material, which may occur in the case of an embossed concave lid material. The effectiveness of the flat inner surface in reducing adhesion allows for a reduced amount of liquid (e.g., brine) in the cavity; at the same time, the reduced amount of liquid and the flat inner surface (except for any concave-convex elements) facilitate the formation of a space between the top surface of the brine and at least some portions of the inner surface of the lid material.

[0012] Due to the reduced brine fill volume and the presence of an air gap above the liquid top surface, the opportunity for interaction between the lid material and the brine during heat sealing is limited, and the space between at least some portions of the brine top surface and the top of the cavity limits the likelihood of the brine leaving the cavity before heat sealing; both reduce the likelihood of quality issues associated with brine falling on the packaging surface to be heat-sealed or on the conveyor belt or machinery used in the packaging process. In addition, when the lens user opens the package, less brine is likely to leave the cavity.

[0013] One aspect of the present invention relates to a contact lens package that includes a blister package defining a cavity, a contact lens disposed in the cavity in a stress-free state, and a lens moisturizing liquid that partially fills the cavity. A lid member is sealed to the blister package such that a section of the lid member engages with the cavity to form an enclosure for the lens and the lens moisturizing liquid. The section has an inner surface that includes at least one uneven element; the inner surface is flat except for the at least one uneven element. An air gap is disposed between the top surface of the lens moisturizing liquid and at least a portion of the inner surface.

[0014] In some embodiments, the lens moisturizing liquid fills at most 99% of the volume of the cavity.

[0015] The at least one uneven element may include a periodic structure. The structure may be periodic along a line extending through the center of the section.

[0016] The at least one uneven element may include an aperiodic structure along a line extending through the center of the section.

[0017] In some embodiments, the at least one uneven element consists of a single uneven element.

[0018] The outer surface of the lid member may be flat. The lid member may include an innermost layer that is a plastic resin.

[0019] Another aspect of the present invention relates to a contact lens package that includes a blister package defining a cavity, a contact lens disposed in the cavity in a stress-free state, and a lens moisturizing liquid that partially fills the cavity. A lid member is sealed to the blister package such that a section of the lid member engages with the cavity to form an enclosure for the lens and the lens moisturizing liquid. The section has an inner surface that includes at least one dome-shaped uneven element. The inner surface is flat except for the at least one uneven element.

[0020] In some embodiments, the lens moisturizing liquid fills at most 99% of the cavity volume.

[0021] In some embodiments, the at least one uneven element includes a periodic structure. The structure may be periodic along a line extending through the center of the section.

[0022] In some embodiments, the at least one uneven element includes an aperiodic structure along a line extending through the center of the section.

[0023] Another aspect of the present invention relates to a method of manufacturing a contact lens package, comprising: (1) producing a structure including a blister package defining a cavity, a contact lens disposed in the cavity, a lens moisturizing liquid partially filling the cavity, and a cover material sealed to the blister package such that a cover material section combines with the cavity to form a sealed space for the lens and the lens moisturizing liquid; (2) testing the leakage of the structure by applying pressure to the cover material using a die having a profile corresponding to at least one uneven element, whereby the pressure forms at least one buffer element on the inner surface of the cover material.

[0024] The term "uneven element" as used herein refers to a feature formed on the inner surface of the cover material that has a height difference relative to the directly surrounding portion of the cover material, and the feature is shaped to have a transition in height such that a contact lens encapsulated in the blister package cavity by the cover material cannot or is less likely to continuously adhere (i.e., conform) to the cover material across the uneven element. It should be understood that the ability of the lens to conform to the cover material across the uneven element is determined at least in part by the elastic modulus of the lens material, the lens edge design (a thicker edge is less likely to conform), and the thickness of the lens profile. The uneven element can be in the form of a recess or a protrusion.

[0025] The term "flat" as used herein means without any machining that applies a profile (e.g., no depression (i.e., no pit) extending substantially the entire distance between opposite sides of a heat seal). It should be understood that a cover material without machining to add a profile thereto (e.g., a conventional multi-layer packaging foil) typically has local deviations in its surface slope, and the heat sealing process may create local profiles near the heat seal; notwithstanding these deviations, the cover material can still be "flat" or "substantially flat" on the cavity of the blister package. The flat cover material is substantially horizontal between opposite sides to which the cover material adheres to the blister package, except for the artifacts of the heat sealing process and any uneven elements near the opposite sides.

[0026] The term "stress-free state" refers to a state of the lens in which the lens is not compressed by opposite surfaces (e.g., opposite surfaces of the package) such that the lens is flattened by the opposite surfaces beyond the lens shape determined by gravity and the liquid in which the lens is immersed.

[0027] The term "dome-shaped" refers to a shape having a continuous curvature throughout the area. A dome-shaped surface forms a discontinuity at the junction of the dome-shaped surface and a flat surface. For example, a dome-shaped surface can be formed by a part of a sphere, an ellipsoid, an ellipsoid, or an ovoid.

[0028] The term "cavity" includes any concave portion (usually dome-shaped) of the blister pack in which the contact lens is normally located when the lens package is face-up, and also includes any other round or angled portion of the blister pack that is fluid-coupled to the concave portion (e.g., see portion E in FIG. 1). The volume of the cavity is determined by the space encapsulated by and below the plane extending between the surfaces to which the cover material is to be attached.

[0029] These and other aspects of the invention will become apparent after reading the following detailed description and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Exemplary, non-limiting embodiments of the invention will be described by way of example with reference to the accompanying drawings, in which like reference numerals are used in different figures to indicate the same or similar components, and in which:

[0031] FIG. 1 is a schematic cross-sectional side view of an inverted conventional contact lens package, in which the force exerted by the air bubble present in the cavity exacerbates the adhesion of the lens to the cover material;

[0032] Figure 2A is a schematic cross-sectional side view of an example of a contact lens package according to an aspect of the present invention;

[0033] Figure 2B is shown separately from the rest of the package for ease of description Figure 2A a schematic plan view of the inner side of the cover material of the lens package in;

[0034] Figures 3A-3B is a plan view and a side view of an example of a concavo-convex element structure formed on the cover material according to an aspect of the present invention, the cover material being flat except for the concavo-convex element structure;

[0035] Figures 3C-3D is a plan view and a side view of an example of a concavo-convex element structure formed on the cover material according to an aspect of the present invention, the cover material being flat except for the concavo-convex element structure; and

[0036] Figures 3E-3F is a plan view and a side view of an example of a concavo-convex element structure formed on the cover material according to an aspect of the present invention, the cover material being flat except for the concavo-convex element structure. DETAILED DESCRIPTION

[0037] Aspects of the invention will be further described below in connection with specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the claimed invention.

[0038] Figure 2A is a schematic cross-sectional side view of an example of a contact lens package 200 according to an aspect of the present invention.

[0039] Figure 2B is a plan view of the lid member 230 of the contact lens package 200. The contact lens package 200 includes a blister package 220 that defines a cavity C. The contact lens 50 is disposed in the cavity C in a stress-free state, and the contact lens wetting solution 210 partially fills the cavity C. The cavity C has an ellipsoidal portion in which the contact lens 50 is located.

[0040] The lid member 230 is sealed to the blister package 220 at a sealing zone L around the perimeter P such that a section S of the lid member combines with the cavity C to form a sealed space for the lens 50 and the lens wetting solution 210. The section S has an inner surface I that includes at least one uneven element 232. Figure 2A Representative uneven elements 232a–232g are shown therein. The inner surface I is flat, except for the bulge BU adjacent to the perimeter P caused by the leak detection process (described below) and at least one uneven element 232. In other words, as Figure 2A shown, the inner surface I, except for the bulge BU and at least one uneven element 232 caused by the leak detection process, is at a substantially uniform distance from the bottom B of the cavity C (measured perpendicular to the flat portion of the surface I) to the plane tangent to the bottom B of the blister package.

[0041] The lid member 230 can be made of any conventional lid member material for contact lenses that can form a buffer element therein, such as a conventional multi-layer packaging foil. Such multi-layer foils typically have at least one layer of flexible metal (such as aluminum) and at least one layer of plastic resin. The innermost layer is typically plastic. The lens wetting solution 210 can be any conventional lens wetting solution (such as saline or pure water). The blister package 220 can be made of any conventional blister package for contact lenses. For example, the blister package can be made of polypropylene, polyethylene, polyvinyl chloride, or polystyrene.

[0042] An air gap 240 is disposed between the top surface TS of the lens wetting solution 210 and at least a portion of the inner surface. Typically, the lens wetting solution fills at most 99% of the volume of the cavity. In some embodiments, the lens wetting solution fills at most 98% of the volume of the cavity; in some embodiments, the lens wetting solution fills at most 95% of the volume of the cavity; in some embodiments, the lens wetting solution fills at most 90% of the volume of the cavity. It should be understood that the shape of the air gap may be affected at least by water tension and the cohesive force with the foil and the blister package; in some embodiments, the air gap may appear as a bubble. As described above, the presence of the air gap provides several quality-related benefits.

[0043] The presence of at least one uneven element on the inner surface of the cover material prevents the lens from adhering to the cover material; however, by configuring the inner surface I (except for at least one uneven element 132) to be flat, the resistance of the lens to adhere to the inner surface of the cover material can be increased. For example, because the lens is small, it may fit the flat shape. In addition, as described above, configuring the inner surface I (except for at least one uneven element 132) to be flat results in less adhesion of the lens, so less moisturizing liquid can be provided in the lens package, thereby reducing the incidence of quality problems and mechanical-related problems associated with the departure of the lens moisturizing liquid from the package during the packaging process.

[0044] In some cases, such as Figure 3A and 3B shown, at least one uneven element 332 includes a repeating pattern of cylindrical uneven elements on the subsection S, and the inner surface I of the subsection S, except for at least one uneven element 332, is flat. Generally, it is desirable that the size and shape of at least one uneven element 332 relative to the size of the subsection S and the circumference of the packaged lens are such that at least one uneven element does not allow continuous contact between the cover material and the circumference of the packaged lens. In Figure 3A and 3B it is evident that at least one uneven element forms a periodic structure along the line D extending through the center CT of the subsection S. In other embodiments containing multiple uneven elements, there is no line D extending through the center CT along which there is a repeating structure.

[0045] In other cases, such as Figure 3C and 3D shown, at least one uneven element consists of a single notch-shaped uneven element 334 extending through the diameter of the subsection S, and the inner surface I of the subsection S, except for at least one uneven element 334, is flat. Generally, it is desirable that a single uneven element (e.g., uneven element 334) spanning the subsection S extends through or is close to the center point of the subsection S such that the relative sizes of the subsection S and the circumference of the packaged lens do not allow continuous contact between the cover material and the lens circumference.

[0046] In other cases, such as Figure 3E and 3F shown, at least one uneven element 336a - 336f (collectively 336) does not include a repeating structure pattern, and the inner surface I of the cover material 337, except for at least one uneven element 336, is flat. The non-repeating structure 336 includes five spherical or ellipsoidal protrusions 336a–336e forming a circle, and one spherical protrusion 336f in the middle of the circle. Although Figure 3E and 3F show spherical uneven elements, other dome-shaped protrusions can also be used.

[0047] It should be understood that the discontinuity at the junction of the domed surface and the flat sheet, as well as the variation along the height of the uneven element, are used to reduce the possibility of the lens being suction-cup adsorbed to the cover material or prevent the lens from being suction-cup adsorbed to the cover material. Another advantage of the domed uneven element over other shapes is that a surface with a continuous curvature is formed within the uneven element instead of a surface with discontinuities, and it is less likely to damage the cover material due to the pressure applied during the formation of the uneven element.

[0048] Although Figure 3A –3F, the example of the uneven element shown has features large enough to be visible to the naked eye, it should be understood that at least one uneven element can also be of a scale that is not visible to the naked eye.

[0049] For example, in order to be used with a typical silicone hydrogel (e.g., kalifilicon A), uneven elements in the shape of a sphere with a radius of curvature of about 4 - 6 mm and a diameter of about 4 - 6 mm can be used. In some cases, the overall height of the uneven element (relative to the flat part of the foil) is about 0.25 - 0.5 mm. Uneven elements with different curvatures and / or diameters from each other can be used on a given foil. In some embodiments, it is advantageous for the uneven elements to share a common tangent plane at their vertices.

[0050] For the purpose of preventing suction-cup adsorption, the cover material should have an inner surface on which uneven elements are formed; however, the outer surface E of the cover material may or may not have a profile corresponding to the uneven elements. In some cases, it is preferred that the outer surface does not have a corresponding profile, so that the outer surface is flat. A flat outer surface can, for example, facilitate printing on the outer surface.

[0051] The uneven elements can be formed in any suitable manner, for example, by using an embossing technique to press a die (also called a mold) having a profile corresponding to the uneven structure to be formed on the cover material, or by using additive manufacturing or subtractive manufacturing techniques.

[0052] The embossing process of applying at least one uneven element to the cover material can be carried out at any time point before or after heat sealing; however, it is generally advantageous to form the uneven pattern at a time different from the time of heat sealing formation to avoid affecting the integrity of the heat seal. In addition, in some cases, it is advantageous to combine the step of forming at least one uneven element with another step (i.e., combine it with the steps carried out at the processing stations described above) to achieve time and energy efficiency.

[0053] In some embodiments, the mold for leak testing is machined to form a desired concave-convex pattern thereon such that when pressure is applied to the lid material through the mold to test for leaks (i.e., leaks of air or a moisturizing liquid), a concave-convex pattern is formed on the lid material. The bottom surface of the mold is flat except for the portions where the concave-convex elements are formed. The diameter of the bottom surface is generally approximately equal to (but less than) the diameter of the blister pack cavity. The bottom of the mold adjacent to the bottom surface and the radially outward portion of the bottom surface may have a circular bevel. When pressure is applied to the lid material, the beveled portion creates a contour in the lid material at a location adjacent to the heat seal (see, e.g., Figure 2A the protruding BU shown). Another technique for forming the concave-convex structure uses a cylindrical roller; when using the roller, a contour corresponding to the concave-convex structure is formed on the roller, and the roller is rolled along the inside or outside of the lid material to form the concave-convex structure on the lid material. It should be understood that if the concave-convex structure is formed by applying force inside the lid material, the pattern on the roller will be the reverse of the pattern to be formed on the inner surface of the lid material.

[0054] Regardless of the technique used to apply the concave-convex pattern, the goal is to apply a force to the packaging foil that is higher than the yield strength of the foil so that the pattern remains on the packaging foil after the force is applied, but lower than the point that causes failure at any location along the foil, thereby avoiding the formation of holes in any layer of the foil. As described above, a pattern with dome-shaped elements helps to avoid failure during the formation of the concave-convex elements.

[0055] Although various embodiments have been described and illustrated in detail herein, it will be apparent to those skilled in the relevant art that various modifications, additions, substitutions, and the like can be made without departing from the spirit of the invention, and thus these are all considered to be within the scope of the invention as defined in the claims below.

[0056] Other embodiments of the invention are defined in the following clauses:

[0057] Clause 1: A contact lens package, comprising:

[0058] A blister pack defining a cavity;

[0059] A contact lens disposed in the cavity in a stress-free state;

[0060] A lens moisturizing liquid partially filling the cavity;

[0061] A lid material sealed to the blister pack such that a section of the lid material combines with the cavity to form a sealed space for the lens and the lens moisturizing liquid, the section having an inner surface including at least one concave-convex element, and the inner surface except the at least one concave-convex element being flat; and

[0062] An air gap disposed between the top surface of the contact lens moisturizing liquid and at least a portion of the inner surface.

[0063] 2. The package according to clause 1, wherein the lens moisturizing liquid fills at most 99% of the volume of the cavity.

[0064] 3. The package according to clause 1, wherein the lens moisturizing liquid fills at most 98% of the volume of the cavity.

[0065] 4. The package according to clause 1, wherein the lens moisturizing liquid fills at most 95% of the volume of the cavity.

[0066] 5. The package according to clause 1, wherein the lens moisturizing liquid fills at most 90% of the volume of the cavity.

[0067] 6. The package according to any one of the preceding clauses, wherein the at least one concave-convex element comprises a periodic structure.

[0068] 7. The package according to clause 6, wherein the structure is periodic along a line extending through the center of the section.

[0069] 8. The package according to clause 1, wherein the at least one concave-convex element comprises an aperiodic structure extending along the flat portion of the cover material and all lines extending through the center of the section.

[0070] 9. The package according to clause 1, wherein the at least one concave-convex element consists of a single concave-convex element.

[0071] 10. The package according to clause 1, wherein the outer surface of the cover material is flat.

[0072] 11. The package according to clause 1, wherein the cover material comprises an innermost layer, and the innermost layer is a plastic resin.

[0073] 12. A contact lens package, comprising:

[0074] A blister package defining a cavity;

[0075] A contact lens disposed in the cavity in a stress-free state;

[0076] A lens moisturizing liquid partially filling the cavity;

[0077] A cover material sealed to the blister package such that a section of the cover material combines with the cavity to form a sealed space for the lens and the lens moisturizing liquid, and the inner surface of the section has at least one dome-shaped concave-convex element, and the inner surface except the at least one concave-convex element is flat.

[0078] 13. The package according to clause 12, wherein the lens moisturizing liquid fills at most 99% of the volume of the cavity.

[0079] 14. The package according to clause 12, wherein the lens moisturizing liquid fills at most 95% of the volume of the cavity.

[0080] 15. The package according to clause 12, wherein the at least one concave-convex element includes a periodic structure.

[0081] 16. The package according to clause 15, wherein the structure is periodic along a line extending through the center of the section.

[0082] 17. The package according to clause 12, wherein the at least one concave-convex element includes an aperiodic structure extending along the flat portion of the cover material and all lines extending through the center of the section.

[0083] 18. A method of manufacturing a contact lens package, comprising:

[0084] producing a structure that includes: a blister package defining a cavity; a contact lens disposed in the cavity; a lens moisturizing liquid partially filling the cavity; and a cover material sealed to the blister package such that a section of the cover material combines with the cavity to form a sealed space for the lens and the lens moisturizing liquid; and

[0085] testing the leakage of the structure by applying pressure to the cover material using a mold having a profile corresponding to at least one concave-convex element, whereby the pressure forms at least one concave-convex element on the inner surface of the cover material.

Claims

1. A contact lens package, comprising: A blister package defining a cavity; A contact lens disposed in the cavity in a stress-free state; A lens moisturizing liquid partially filling the cavity; A cover material sealed to the blister package such that a section of the cover material combines with the cavity to form a sealed space for the lens and the lens moisturizing liquid, the section having an inner surface including at least one uneven element, and the inner surface except the at least one uneven element is flat; And An air gap disposed between the top surface of the contact lens moisturizing liquid and at least a part of the inner surface.

2. The package according to claim 1, wherein the lens moisturizing liquid fills at most 99% of the volume of the cavity.

3. The package according to claim 1, wherein the lens moisturizing liquid fills at most 98% of the volume of the cavity.

4. The package according to claim 1, wherein the lens moisturizing liquid fills at most 95% of the volume of the cavity.

5. The package according to claim 1, wherein the lens moisturizing liquid fills at most 90% of the volume of the cavity.

6. The package according to any one of the preceding claims, wherein the at least one uneven element includes a periodic structure.

7. The package according to claim 6, wherein the structure is periodic along a line extending through the center of the section.

8. The package according to any one of claims 1 to 5, wherein the at least one uneven element includes an aperiodic structure extending along all lines of the flat part of the cover material and extending through the center of the section.

9. The package according to any one of claims 1 to 5 or 8, wherein the at least one uneven element consists of a single uneven element.

10. The package according to any one of the preceding claims, wherein the outer surface of the cover material is flat.

11. The package according to any one of the preceding claims, wherein the cover material includes an innermost layer which is a plastic resin.

12. A contact lens package, comprising: A blister package defining a cavity; A contact lens disposed in the cavity in a stress-free state; A lens moisturizing liquid partially filling the cavity; A cover material sealed to the blister package such that a section of the cover material combines with the cavity to form a sealed space for the lens and the lens moisturizing liquid, the section having an inner surface including at least one dome-shaped uneven element, and the inner surface except the at least one uneven element is flat.

13. The package according to claim 12, wherein the lens moisturizing liquid fills at most 99% of the volume of the cavity.

14. The package according to claim 12, wherein the lens moisturizing liquid fills at most 95% of the volume of the cavity.

15. The package according to any one of claims 12 to 14, wherein the at least one uneven element includes a periodic structure.

16. The package according to claim 15, wherein the structure is periodic along a line extending through the center of the section.

17. The package according to any one of claims 12 to 14, wherein the at least one relief element comprises an aperiodic structure along all lines extending along the flat portion of the cover sheet and extending through the center of the section.

18. A method of manufacturing a contact lens package, comprising: producing a structure, the structure comprising: a blister package defining a cavity; a contact lens disposed in the cavity; a lens moisturizing liquid partially filling the cavity; and a cover sheet sealed to the blister package such that a section of the cover sheet is joined to the cavity to form a sealed space for the lens and the lens moisturizing liquid; and testing the leakage of the structure by applying pressure to the cover sheet using a die having a profile corresponding to the at least one relief element, whereby the pressure forms the at least one relief element on the inner surface of the cover sheet.

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