Contact lens package integrity testing

Abstract

A method may include: introducing a contact lens blister pack into a sterilizer unit, wherein the contact lens blister pack comprises a package base having a cavity, a contact lens disposed in the cavity, a packaging solution disposed in the cavity, and a material forming a seal over the cavity; controlling operating conditions of the sterilizer unit such that at least a portion of the packaging solution is evacuated from the contact lens blister pack if there is a defect in the contact lens blister pack; introducing the contact lens blister pack into a package integrity testing unit; detecting whether the contact lens blister pack has a defect based at least on an amount of packaging solution remaining.

Description

CONTACT LENS PACKAGE INTEGRITY TESTINGRELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 549,709, filed February 5, 2024.BACKGROUND

[0002] Contact lens blister packaging is a relatively economical option for storage of the lens prior to use by a wearer. The traditional blister pack for disposable lenses includes a package base comprising a well surrounded by a flange. The well contains the contact lens and packaging solution and is sealed along a seal region by a removable lid typically made of film, for example, a multilayer film comprising a sealing layer and a foil layer. The contact lens base is usually thermoformed plastic material produced by injection molding of polyethylene, polypropylene, polyvinyl chloride, or polyethylene terephthalate. The contact lens base has high stiffness but is capable of limited plastic deflection and includes a pre-formed well. The well is filled with a suitable packaging solution, preferably a buffered saline solution, and receives a single lens into the well. The well is then sealed and sterilized (e.g., autoclaved) using steam and pressure.

[0003] The package base serves several important functions for contact lenses. The package base protects the lens during transportation and keeps the contact lens hydrated by keeping the contact lens immersed in packaging solution. Package bases may be designed to support the immersed lens with the convex surface of the lens facing the removable lid or, with the concave (corneal contact) surface of the lens facing the removable lid. The package base also supports the lens such that during transportation, the lens does not fold or invert (which may result in incorrect application and use of the lens).

[0004] Package integrity testing is an important step in the production of contact lenses. The contact lens packaging must be leak proof to remain sterile and keep the lens hydrated. Current methods of package integrity testing require a technician to pull a representative amount of sample packages from each lot manufactured. The samples may be then subjected to a dye ingress test whereby the lens packages are submerged in a dye under vacuum. For contact lens packages with a defect, the dye may be pulled into the defective package under vacuum and thus be identifiable. If a package is deemed defective, the manufactured lot is disposed. While dye ingress testing is effective at determining if an individual package is defective, dye ingress testing is unable to detectevery defect in a manufactured lot. If a defective package is not in the representative sample, for example, the defective package may not be detected. Further, the dye ingress testing is time consuming and requires a quality control operator to physically select and handle each representative lot of samples and insert the samples into the dye and vacuum chamber. During the quality control testing, the manufactured lots may be placed on hold increasing work in progress (WIP) and lead time for manufactured lots.SUMMARY

[0005] Disclosed herein is an example method including: introducing a contact lens blister pack into a sterilizer unit, wherein the contact lens blister pack comprises a package base having a cavity, a contact lens and packaging solution disposed in the cavity, and a film forming a seal over the cavity; controlling operating conditions of the sterilizer unit such that at least a portion of the packaging solution is evacuated from the contact lens blister pack if there is a defect in the contact lens blister pack; and detecting whether the contact lens blister pack has a defect based at least on an amount of packaging solution remaining.

[0006] Further disclosed herein is another example method including: introducing a contact lens blister pack into a sterilizer unit, wherein the contact lens blister pack comprises a package base having a cavity, a contact lens and packaging solution disposed in the cavity, and a material forming a seal over the cavity, wherein the contact lens blister pack comprises a defect; controlling operating conditions of the sterilizer unit such at least a portion of the packaging solution is evacuated from the contact lens blister pack through the defect; and introducing the contact lens blister pack into a package integrity testing unit and detecting the defect.

[0007] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory in nature and are intended to provide an understanding of the present disclosure without limiting the scope of the present disclosure. In that regard, additional aspects, features, and advantages of the present disclosure will be apparent to one skilled in the art from the following detailed description.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] These drawings illustrate certain aspects of embodiments of the present invention and should not be used to limit or define the invention.

[0009] FIG. 1 is a schematic perspective view of an apparatus for the sterilization and secondary packaging of arrays of interconnected blister packages for the sterilized containment of contact lenses.

[0010] FIG. 2 is a phase diagram which illustrates a sterilization cycle.

[0011] FIG. 3 is a phase diagram which illustrates another sterilization cycle.

[0012] FIG. 4a is a schematic illustration of a blister package array.

[0013] FIG. 4b is a side view schematic illustration of a blister package array.

[0014] FIG. 4c is a schematic illustration of two blister package arrays nested together with the seal facing outwards.

[0015] FIG. 5 illustrates a method to identify a defective blister package.

[0016] FIG. 6 illustrates a method to identify a defective blister package.

[0017] FIG. 7 illustrates a method to identify a defective blister package.

[0018] FIG. 8 illustrates an apparatus for implementing the method of FIG. 7.DETAILED DESCRIPTION

[0019] Disclosed herein are methods of detecting defects in contact lens packaging, and more particularly disclosed herein are methods of detecting defects in contact lens packaging using a sterilization unit to evacuate a portion of a liquid within a contact lens packaging and detecting a change in volume of the liquid within the contact lens packaging.

[0020] Examples of the package integrity testing method include utilizing a sterilization unit to evacuate a portion of a liquid within a contact lens package and detecting a change in volume of the liquid within the contact lens package. The example methods provide several advantages over the previous methods of contact lens package integrity testing, only some of which may be alluded to herein. The example method of package integrity testing allows for in-line testing of every contact lens package manufactured on a manufacturing line and thus quality may be assured for each contact lens package released to customers. The example methods also individually identify defective contact lens packages within a manufactured lot such that only the contact lens packages deemed defective are disposed of thus saving the remainder of the manufactured lot from being unnecessarily disposed of. The example in-line package integrity testing methods also reduce work in progress by eliminating the need to store manufactured lots while a representative sample of the manufactured lot is tested. The example methods of package integrity testing also allow for removal of several pieces of equipment and chemicals from the manufacturing process, as thevacuum equipment and dye solutions are not required for the present methods, which reduces the number of waste streams associated with the manufacture of contact lenses. Additionally, the example methods may be automated thereby eliminating the need for an operator to manually handle the representative samples of contact lens packages thus reducing overhead costs associated with manufacturing the contact lens packages.Contact Lens Manufacturing Process

[0021] Contact lenses may be formed by introducing reactive mixtures into a mold where the mold defines the optical properties of the contact lens. The reactive mixtures may be cured by light and / or heat to form the contact lens. After curing, the contact lens may be removed from the mold, subject to various processing steps such as hydration and extraction, and transferred to a packaging step where the contact lens may be deposited into a package base with a packaging solution. The finished blister pack containing the contact lens may then be sterilized, such as in an autoclave, before final packaging into cartons.

[0022] In a first step of contact lens manufacturing, reactive mixtures may be formed into contact lenses by dispensing the mixture into a mold assembly and subsequently curing the mixture. The mold assembly may include a base curve, which may be the mold half that contacts the posterior surface of the lens, and a front curve, which may be the mold half that contacts the anterior surface of the lens. The front curve and base curve, when brought together, may define and enclose a cavity between them which contains the reactive mixture.

[0023] The mold components (front curve and base curve) of the mold assembly may be made from various materials, including disposable or reusable materials. For instance, the mold may include a thermoplastic optical mold. The mold assembly may be made from any suitable material including, without limitation, polyethylene, polypropylene, polyolefins including homopolymers, copolymers, and terpolymers, polystyrene, polystyrene copolymers, polyesters such as poly(ethylene terephathalate) and poly(butylene terephthalate), polyamides, poly(vinyl alcohol) and its derivatives, hydrogenated styrene butadiene block copolymers, cyclic olefin polymers (COP) and copolymers (COC), and combinations thereof. COP plastic resins are commercially available from Zeon Chemicals (Zeonex and Zeonor resins), and Japan Synthetic Rubber (JSR). COC plastic resins are commercially available from Topas Advanced Polymers (Topas resins) and Mitsui (APEL resins). The mold may be selected to be transparent or mostly transparent to wavelengths that may activate the photoinitiator, thus permitting irradiation through the front andbase curves. The material may be the same or different in the front and base curves. Examples of materials for the front curve of the mold assembly may include COP such as Zeonor 1060R or COC such as Topas 8007 or 5013 either neat or as a blend for example about 90: 10 (w / w) blend of COC or COP and hydrogenated styrene butadiene block copolymer, respectively. Examples of suitable materials for the base curve of the mold assembly may include COC, COP described above, polypropylene, blends thereof and blends with hydrogenated styrene butadiene block copolymer, about 90:10 (w / w) blend of cyclic olefin polymer and polypropylene.

[0024] Sources of activating radiation for initiating the photoinitiators may include, without limitation, heat or lamps that transmit light at the appropriate wavelengths for such initiation. One method may include emitting activating radiation from a light emitting diode (LED) lamp. LED lamps may be utilized that transmit at the desired intensity and at a range of wavelengths that include from about 200 nanometers (nm) to about 600 nm. Alternatively, from about 300 nm to about 500 nm, most preferably from about 350 nm to about 450 nm.

[0025] The curing step may be carried out by exposing the reactive mixture to heat or radiation or a combination thereof that includes the activating wavelength (the wavelength required to activate the photoinitiator). Radiation may be directed at either or both the base curve and the front curve of the mold assembly. The radiation may have a radiant energy at the base curve which may be greater than the radiation's radiant energy at the front curve.

[0026] The intensity of the radiation may generally be in the range of from about 0.1 mW / cm2to about 25 mW / cm2. Alternatively, from about 1 mW / cm2to about 10 mW / cm2, about 1 mW / cm2to about 15 mW / cm2, about 15 mW / cm2to about 25 mW / cm2, or any ranges therebetween.

[0027] After curing, the lens may be subjected to additional processing steps such as hydration to swell the lens, extraction to remove unreacted components from the lens, and release of the lens from the lens mold. These steps may take place in any order. The extraction may be carried out using extraction fluids, including, but not limited to, organic solvents, alcohols, aqueous solutions comprising water, and mixtures thereof. Examples of the aqueous solutions may include at least about 20 weight percent water, or at least about 50 weight percent water, or at least about 70 weight percent water, or at least about 95 weight percent water. Aqueous solutions may also include additional water-soluble compounds such as inorganic salts or release agents, wetting agents, slip agents, pharmaceutical and nutraceutical formulas, and combinations thereof. Release agents may include compounds or mixtures of compounds which, when combined with water, decrease thetime required to release a contact lens from a mold, as compared to the time required to release such a lens using an aqueous solution that does not comprise the release agent.

[0028] Extraction may be accomplished, for example, via immersion of the lens in an extraction fluid or exposing the lens to a flow of an extraction fluid. Extraction may also include, for example, one or more of: heating the extraction fluid; stirring the extraction fluid; increasing the level of release aid in the extraction fluid to a level sufficient to cause release of the lens; mechanical or ultrasonic agitation of the lens; and incorporating at least one leaching or extraction aid in the aqueous solution to a level sufficient to facilitate adequate removal of unreacted components from the lens. The foregoing may be conducted in batch or continuous processes, with or without the addition of heat, agitation, or both. Before or after extraction of the lens and removal of the lens from the lens mold, the lens may be hydrated.

[0029] The lens may then be transferred to a packaging process where the lens and a packaging liquid may be deposited into a package base having a well therein. The packaging liquid may include an isotonic saline solution to prevent dehydration and to maintain the lenses in a ready-to- wear condition. The package base may be hermetically sealed with any suitable seal material including, for example, an aluminum laminate foil which may include aluminum sandwiched between layers of polyester printing materials and oriented polypropylene, to form a contact lens blister pack. The contact lens blister packs may be joined together by a continuous sheet of foil with perforations therein to provide blister pack arrays comprising two or more individual blister packs, wherein the perforations align on an edge between the blister packs such that individual blister packs may be separated from the blister pack array. The packaged lens may be then transferred to a sterilization process where packaged lenses may be sterilized by placing the blister pack in a sterilizing unit, such as an autoclave, at an elevated humidity, temperature, and pressure for a period of time.Reactive Mixture

[0030] ‘ ‘Conventional hydrogels” refer to polymeric networks made from components without any siloxy, siloxane or carbosiloxane groups. Conventional hydrogels may be prepared from reactive mixtures comprising hydrophilic monomers. Examples include 2-hydroxyethyl methacrylate (“HEMA”), N-vinyl pyrrolidone (“NVP”), N, N-dimethylacrylamide (“DMA”) or vinyl acetate. Conventional hydrogels may also be formed from polyvinyl alcohol. Conventional hydrogel lenses may contain a coating, and the coating may be the same or different material from the substrate.Conventional hydrogels may include additives such as polyvinyl pyrrolidone, and comonomers including phosphoryl choline, methacrylic acid and the like. Examples of conventional hydrogels include, but are not limited to, etafilcon, genfilcon, hilafilcon, lenefilcon, nesofilcon, omafilcon, polymacon, and vifilcon, including all of their variants.

[0031] “ Silicone hydrogels” refer to polymeric networks made from at least one hydrophilic component and at least one silicone-containing component. Examples of suitable families of hydrophilic components that may be present in the reactive mixture include (meth)acrylates, styrenes, vinyl ethers, (meth)acrylamides, N-vinyl lactams, N-vinyl amides, N-vinyl imides, N- vinyl ureas, O-vinyl carbamates, O-vinyl carbonates, other hydrophilic vinyl compounds, and mixtures thereof. The silicone-containing component may comprise at least one polymerizable group (e.g., a (meth)acrylate, a styryl, a vinyl ether, a (meth)acrylamide, an N-vinyl lactam, an N- vinylamide, an O-vinylcarbamate, an O-vinylcarbonate, a vinyl group, or mixtures of the foregoing), at least one siloxane group, and one or more linking groups (which may be a bond) connecting the polymerizable group(s) to the siloxane group(s). The silicone-containing components may, for instance, contain from about 1 siloxane repeat unit to about 220 siloxane repeat units. The silicone-containing component may also contain at least one fluorine atom. Silicone hydrogel lenses may contain a coating, and the coating may be the same or different material from the substrate. Examples of suitable silicone hydrogels may include acquafilcon, asmofilcon, balafilcon, comfilcon, delefilcon, enfilcon, fanfilcon, formofilcon, galyfilcon, kalifilcon, lotrafilcon, narafilcon, riofilcon, samfilcon, senofilcon, serafilcon, somofilcon, stenfilcon, and verofilcon including all of their variants.Initiators

[0032] The reactive mixture includes a photoinitiator. The photoinitiator may absorb (and be activated by) various wavelengths of light, for instant UV wavelengths and / or visible wavelengths. The photo initiator may absorb within the visible range (about 380 nm to about 780 nm) of the electromagnetic spectrum. Suitable visible light photoinitiators may include, but are not limited to, aromatic alpha-hydroxy ketones, alkoxyoxybenzoins, acetophenones, acylphosphine oxides, bisacylphosphine oxides, and a tertiary amine plus a diketone, mixtures thereof and the like. Examples of photoinitiators may include, but are not limited to, 1 -hydroxy cyclohexyl phenyl ketone, 2-hydroxy-2-methyl-l-phenyl-propan-l-one, bis(2,6-dimethoxybenzoyl)-2,4-4- trimethylpentyl phosphine oxide (DMBAPO), bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide (Irgacure 819), 2,4,6-trimethylbenzyldiphenyl phosphine oxide and 2,4,6- trimethylbenzoyl diphenylphosphine oxide, benzoin methyl ester and a combination of camphorquinone and ethyl 4-(N,N-dimethylamino)benzoate. The initiator may be included in the reactive mixture in effective amounts to initiate photopolymerization of the reactive mixture, including from about 0.1 to about 2 parts by weight per 100 parts of reactive monomer(s).

[0033] The reactive mixture may further include a thermal initiator which decomposes at a certain rate depending on the temperature. A thermal initiator may include, without limitations, an azo compound such as 1 , l'-azobisisobutyronitrile and 4,4'-azobis(4-cyanovaleric acid), peroxides such as benzoyl peroxide, tert-butyl peroxide, tert-butyl hydroperoxide, tert-butyl peroxybenzoate, dicumyl peroxide, and lauroyl peroxide, peracids such as peracetic acid and potassium persulfate, and combinations thereof.Package Integrity Testing:

[0034] FIG. 1 is a schematic representation of an operating structure of an apparatus 100 for implementing the sterilization and package integrity testing as well as secondary packaging of the blister packages into cartons. While FIG. 1 illustrates one method of conveying blister package arrays into sterilization chamber 104, there may be several equivalent methods of conveying blister package arrays known in the art. Additionally, while blister package arrays as described in FIG. 1 are plural, the present methods are applicable to methods where one or more blister individual packs are utilized.

[0035] FIG. 1 illustrates the infeed of the blister package arrays 102 along the direction of arrow A so as to be placed in paired interleaved relationship by a product pick-up and rotating device as in arrows B. The interleaved blister package arrays 102 may be further conveyed to be positioned in spaces present between outwardly extending fingers of an endless loop-type tray loading shuttle conveyor assembly 106 which may be indexed forwardly in the direction of arrow C until all of the spaces along a vertical run thereof may be filled with paired interleaved blister package arrays 102, whereupon the conveyor assembly may be adapted to be temporarily brought to a standstill, and a suitable pusher 108 may transfer a vertical stack of the blister package arrays 102 from the conveyor into a vertical column or row of array-receiving spaces in an upended tray 110. The tray 110 may be intermittently indexed in the direction of arrow D until all of the vertical rows of spaces therein may be filled with interleaved pairs of blister package arrays 102. While FIG. 1 showsinterleaved blister package arrays, a single blister package array or an individual contact lens blister package may be inserted into tray 110.

[0036] As further illustrated in FIG. 1, the array-filled tray 110 is conveyed along the direction of arrow E, while being prior thereto rotated in the direction of arrow F into a horizontal position and may be stacked with other similarly filled trays 110 to be conveyed into a sterilization chamber 104. The sterilization chamber 104 may include an autoclave. As will be discussed below, the sterilization chamber 104 may be operated in such a manner as to cause at least a portion of the packaging fluid present in defective blister package arrays 102 to escape from the blister package. From the sterilization chamber 104, the stacks of trays 110 with the blister package arrays 102 contained therein, may then be conveyed along the direction of the arrow G and introduced into package integrity testing unit 112. In package integrity testing unit 112, the sterilized blister packages 102 may be subjected to non-destructive testing to determine if there are any defective blister package arrays 102. The operation of package integrity testing unit 112 will be described in detail below. Defective packages may be removed from circulation as indicated by arrow R and the remaining non-defective packages may be conveyed to packaging as indicated by arrow H where the trays may be unstacked and individually advanced and upended in succession. The upended tray 110 may be positioned in alignment with an unloading shuttle conveyor assembly 116 to enable a pusher member to sequentially engage into vertical rows of spaces of the tray 110 housing the arrays of blister packages and transfer the latter into spaces present between outwardly extending fingers on a loop-type endless conveyor of assembly 116. The conveyor may be indexed forwardly in the direction of the arrow I, and a pusher element slides a succession of a plurality of sterilized arrays 102 of blister packages into the open end of a carton 114 which has been brought into alignment therewith by means of a cartoner. The filled cartons 114 may then be closed and sealed and conveyed along arrow J to suitable locations for further handling such as bundling as indicated by arrow K.

[0037] Sterilization chamber 104 includes a chamber for storing the blister package arrays 102 during a sterilization cycle. The chamber may be made of any suitable durable material such as stainless steel or alloys which may withstand the heat and pressure conditions during a sterilization cycle. The chamber may also include one or more doors for providing access to the chamber wherein the door may be designed with a tight seal to prevent leaks during the sterilization cycle. The one or more doors may include locking mechanisms and associated interlocks to prevent thedoor from opening during the sterilization cycle. The sterilization chamber may further include inlets and outlets as well as controllable valves operatively associated with the inlets and outlets to allow for the controlled flow of fluids and gases into the chamber. The sterilization chamber 104 may further include a pressure control system to manage and maintain the desired pressure levels within the chamber and may include components such as pressure relief valves and pressure transducers and / or strain gauges that send pressure data to a control system to monitor and regulate the pressure within the chamber. The sterilization chamber 104 may further include temperature sensors, such as thermocouples or resistance temperature detectors, which send temperature data to the control system to measure and control the temperature inside the chamber. Sterilization chamber 104 further includes a heating system to achieve and maintain the desired temperature within the chamber. The heating system may include electric or steam-powered heaters located either inside the chamber or in an external jacket surrounding it. For steam, a boiler and / or steam- powered heater may be operatively coupled to an inlet of the chamber. Sterilization chamber 104 further includes a control system for operating a sterilization cycle which may be further integrated into a distributed control system for a production line for contact lenses.

[0038] The control system may include a computer-based control system that may be used to monitor and control the different processes in the sterilization chamber. The control system typically comprises a number of components, including: sensors: these devices measure the physical properties of the process, such as temperature, pressure, and flow rate; controllers: these devices use the data from the sensors to calculate the necessary adjustments to the process; actuators: these devices implement the control commands from the controllers, such as opening or closing valves; and a human-machine interface (HMI) which may include a graphical user interface that allows operators to monitor and control the process. The control system uses various types of logic control such as PID controllers, ladder logic, and sequential function charts to control the processes. The logic control may be programmed into the control system software and may be used to ensure the equipment operates within predefined limits.

[0039] A sterilization cycle may be initiated by the control system sending a signal to the controller associated with the steam system to open one or more of the inlet valves to the chamber. Before, during, and after the sterilization cycle, instrumentation reports back to the controller or control system conditions within the various parts of the sterilization chamber 104 such as steam pressure and temperature in lines, plant steam pressure and temperature, radiator pressure, air pressure andtemperature, water pressure and temperature, valve state, and safety interlock state, for example. The sterilization cycle typically includes increasing chamber pressure and temperature to a setpoint, holding the pressure and temperature at the setpoint for a determined period of time, and releasing the pressure while cooling the chamber using air, for example. The sterilization cycle setpoint temperature, pressure, and hold time is selected such that the contact lens blister pack is safely sterilized without compromising the lens or blister pack packaging. The rate of temperature and pressure ramping up and down may be controlled so that the lens and blister packaging is not damaged. For example, reducing the pressure within the chamber may cause the blister packaging to burst if the differential pressure across the seal is greater than the strength of the seal.

[0040] The set point temperature selected may be in a range of about 110 °C to about 140 °C. Alternatively, in a range of about 110 °C to about 120 °C, about 120 °C to about 130 °C, about 130 °C to about 140 °C, or any ranges therebetween. The set point pressure may be selected in a range of about 300 kPa to about 450 kPa. Alternatively, in a range of about 300 kPa to about 350 kPa, about 350 kPa to about 400 kPa, about 400 kPa to about 450 kPa, or any ranges therebetween. The ramp time for the sterilizer unit to reach the temperature set point may be a time in a range of from about 1 minute to about 5 minutes. Alternatively, in a range of about 1 minute to about 2 minutes, about 2 minutes to about 3 minutes, about 3 minutes to about 5 minutes, or any ranges therebetween. The ramp time for the sterilizer unit to reach the pressure set point may be a time in a range of from about 1 minute to about 5 minutes. Alternatively, in a range of about 1 minute to about 2 minutes, about 2 minutes to about 3 minutes, about 3 minutes to about 5 minutes, or any ranges therebetween. The hold time of the sterilizer cycle may be a value in a range of about 10 minutes to about 30 minutes. Alternatively, in a range of about 10 minutes to about 20 minutes, about 20 minutes to about 25 minutes, about 20 minutes to about 30 minutes, or any ranges therebetween. The sterilizer may have a ramp down time for the sterilizer unit to reach atmospheric pressure at a time in a range from about 5 minutes to about 20 minutes. Alternatively, in a range of about 5 minutes to about 10 minutes, about 10 minutes to about 15 minutes, about 15 minutes to about 20 minutes, or any ranges therebetween. The sterilizer may have a ramp down time for the sterilizer unit to reach ambient temperature at a time in a range from about 5 minutes to about 20 minutes. Alternatively, in a range of about 5 minutes to about 10 minutes, about 10 minutes to about 15 minutes, about 15 minutes to about 20 minutes, or any ranges therebetween.

[0041] As discussed above, the contact lens blister packaging may be damaged by the sterilization cycle or other parts of the manufacturing process such as during transportation and handling of the blister packs. Additionally, the blister pack may be defective at the seal formed between the package base and the lid, the lid may be defective, or the package base may be defective such that the sterility of the blister pack may not maintained. For these and other reasons, it may be desirable to have a process to determine whether the blister pack is defective for every blister pack in a manufactured lot. One method to determine if a blister pack contains a defect which would not compromise the sterility of the blister pack may be to select the operating conditions of the sterilization unit such as setpoint temperature, setpoint pressure, and hold time such that a portion of the packaging fluid may be evacuated from a defective blister pack at a point in time before the sterilization cycle, during the sterilization cycle, or after the sterilization cycle. After passing through the sterilization unit, the blister pack may then be analyzed to determine if the blister pack contains a low dose of the packaging solution or is empty of packaging solution.

[0042] There may be several methods to induce a portion of the packaging solution, which contains water as the major ingredient, to evacuate from a defective blister pack. One method may be to increase the temperature and pressure in the sterilization chamber while maintaining the temperature and pressure above the saturation line of water. Once the set point temperature is reached and the hold time is expired, the pressure may be decreased while maintaining a relatively constant temperature such that the pressure and temperature fall below the saturation line for water. If a blister pack contains a defect, a portion of the packaging solution may flash to vapor as the pressure is decreased and subsequently escapes the blister pack. The temperature and pressure in the chamber may then be decreased to ambient temperature and pressure and the sterilization cycle may be completed.

[0043] FIG. 2 is a phase diagram which illustrates the method by which the temperature and pressure may be increased before decreasing the pressure to below the saturation line. In FIG. 2, the method begins at first point 202 in the liquid region of the phase diagram. The method proceeds by increasing pressure and temperature in the sterilizer unit from a first pressure and a first temperature corresponding to first point 202 to a second pressure and second temperature corresponding to second point 204. As shown in FIG. 2, the pressure and temperature in the sterilizer are increased while remaining within the liquid phase region of the phase diagram of water and avoiding entry into a gas phase region of the phase diagram of water. Once at secondpoint 204, the pressure and temperature may be held for a hold time. The method may proceed by decreasing the pressure while maintaining a relatively stable temperature to third point 206 such that the temperature and pressure in the sterilizer unit are in the gas phase region of the phase diagram of water. The conditions in the sterilizer unit may be held at third point 206 for a hold time to allow at least a portion of the packaging solution within a defective blister pack to flash to vapor. The method may then proceed by reducing the temperature and / or pressure such that the conditions within the sterilizer unit correspond to first point 202.

[0044] Another method to evacuate a portion of the packaging solution may be to increase the temperature and pressure in the sterilization chamber while maintaining the temperature and pressure above the saturation line of water. The relative humidity of the air in the chamber may be controlled such that the relative humidity in the chamber may be less than the relative humidity of the head space in the blister packages during the sterilization cycle. The hold time may be selected such that at least a portion of the packaging solution evaporates from the defective blister packages. The temperature and pressure in the chamber may be then decreased to ambient temperature and pressure and the sterilization cycle may be completed.

[0045] FIG. 3 is a phase diagram which illustrates the sterilization cycle while controlling relative humidity. In FIG. 3, the method begins at first point 302 in the liquid portion of the phase diagram a first pressure and a first temperature. The method proceeds by increasing pressure and temperature in the sterilizer unit from a first pressure and a first temperature corresponding to first point 302 to a second pressure and second temperature along path 304 to second point 306. As shown in FIG. 3, the pressure and temperature in the sterilizer are increased while remaining within the liquid phase region of the phase diagram of water and avoiding entry into a gas phase region of the phase diagram of water. Once at second point 304, the pressure and temperature may be held for a hold time while controlling a relative humidity of the sterilizer unit such that the relative humidity of the sterilizer unit is less than a relative humidity within a headspace of the contact lens blister. The hold time may be selected such that a portion of packaging solution in defective blister packs is evaporated from the defective blister packs and is evacuated from the defective blister packs.

[0046] Another method to evacuate a portion of the packaging solution may be to increase the pressure in the chamber between a relatively higher pressure and thereafter decreasing the pressure to a relatively lower pressure in a cyclical manner to “pump” a portion of the packaging solutionout of a defective package. This pumping cycle may be performed before or after the sterilization cycle. A pumping cycle may include increasing pressure in the sterilizer unit from a first pressure to a second higher pressure wherein the second pressure is higher than the first pressure, decreasing pressure in the sterilizer unit from the second pressure to a third pressure, wherein the third pressure is lower than the second pressure, increasing the pressure in the sterilizer unit from the third pressure to a fourth pressure, wherein the fourth pressure is higher than the third pressure; and decreasing the pressure in the sterilizer unit from the fourth pressure to a fifth pressure, wherein the fifth pressure is lower than the fourth pressure. Where there is a defective package, a portion of the packaging solution may be evacuated by at least one of decreasing pressure in the sterilizer unit from the second pressure to the third pressure and / or decreasing the pressure in the sterilizer unit from the fourth pressure to the fifth pressure. While only two pumping cycles are described, the pumping cycle can be repeated any number of times to evacuate a portion of the packaging solution.

[0047] Another method to evacuate a portion of the packaging solution may be to increase the temperature and decrease the pressure in the sterilization chamber to below the saturation line and hold for a period of time to allow for a portion of the packaging solution to flash to vapor and evacuate from the defective blister packages. This pump down cycle may be performed before, during, or after the sterilization cycle.

[0048] A combination of multiple techniques may be combined to evacuate at least a portion of the packaging fluid. For example, a pumping cycle may be performed in combination with a sterilization cycle that features relative humidity control. A pumping cycle may be combined with a sterilization cycle that decreases pressure below the saturation line. A sterilization cycle may include an element of relative humidity control and a pressure drop below the saturation line.

[0049] FIG. 4a is a schematic illustration of a blister package array 102. As illustrated, the blister package array 102 includes five adjacently located contact lens blister packages 401. Each blister package 401 includes a package base 402 having a cavity 404 for the containment of a contact lens 406 immersed in a packaging solution, and with the blister package array 102 being sealingly covered by a single flexible foil seal 408, so as to be separable along perforation lines 410 into individual blister package 401, each respectively containing a single contact lens.

[0050] FIG. 4b is a side profile view of a single blister package array 102. As shown in FIG. 4b, blister package 401 includes cavity 404 being sealed by foil seal 408. FIG. 4c is side profile viewof two interleaved blister package arrays 102 nested together such that the foil seal 408 of each blister package 401 is facing outwards.

[0051] Once the blister package arrays 102 are sterilized and a portion of the packaging solution may be evacuated from a defective blister package, the blister package arrays 102 may be introduced into package integrity testing unit 112. Package integrity testing unit 112 includes a device for determining if a blister package within blister package array 102 may be defective. While the following may be described in relation to blister package arrays, the methods are equivalently applicable to interleaved blister package arrays and individual blister packages.

[0052] FIG. 5 illustrates a method 500 to identify a defective blister package. Method 500 begins by providing blister package arrays 102 from a sterilization process which includes a step to evacuate a portion of the packaging solution from defective blister packages as described above. Method 500 proceeds with heating blister package arrays 102 using a heat source 502. The heating may be accomplished using any suitable methods such as heating the blister package using infrared energy and / or thermal energy. The heating may warm at least one of the foil seal, packaging solution, lens, and / or package base. For defective blister packages which contain a low dose of packaging solution, the amount of heat transferred into the defective package may cause the temperature of the defective packages to be greater than packages which are not defective. After heating, the foil and packaging solution of defective blister packages may be at a higher relative temperature to non-defective blister packages. After heating, the blister package array 102 may positioned under thermographic camera 504 containing a sensor which may be sensitive to infrared wavelengths in ranges from about 1,000 nm to about 14,000 nm.

[0053] There may be several methods to identify defective blister packages including that the bubble size of the packaging solution may be seen through the foil seal 408 by examining the intensity of the infrared radiation emitting from the heated package. The bubble size may be correlated with the amount of packaging solution whereby a nominal dose of packaging solution may have a nominal bubble size and a defective blister package may have a bubble size smaller than the nominal bubble size. Additionally, defective blister packages may be identified by examining the thermal signature of the heated blister package array 102. The defective blister packages may have a different thermal signature due to the increased temperature from heating and thus are identifiable by comparing the observed thermal signature to nominal thermal signature and determining if the observed thermal signature sufficiently matches the nominal thermalsignature. Defective blister packages may also be identified by comparing an average surface temperature of the blister packages to a nominal average surface temperature. Nominal measurements for each of the methods may be readily obtained by measuring a representative sample of known good blister packages. There may be a plurality of thermographic camera 504 positioned to capture thermographic images of various parts of blister package array 102 including, for example, a thermographic camera 504 positioned to capture a side profile image of blister package array 102, or a thermographic camera 504 positioned to capture a bottom profile image of blister package 102, such as a thermographic image of cavity 404. Where the thermographic camera 504 is positioned to capture a thermographic image of cavity 404, the bubble size may be observed through the material of cavity 404. Similarly, an optical camera 506 may be positioned below cavity 404 to measure the bubble size optically.

[0054] FIG. 6 illustrates a method 600 to identify a defective blister package. Method 600 begins by providing blister package arrays 102 from a sterilization process which includes a step to evacuate a portion of the packaging solution from defective blister packages as described above. Method 600 proceeds with measuring a mass of the blister package array 102 using a mass balance 602. The measured mass may be compared to a nominal mass and the blister package array 102 may be deemed defective if the measured mass deviates from the expected nominal mass for the type of contact lens blister package being examined.

[0055] FIG. 7 illustrates a method 700 to identify a defective blister package. Method 700 begins at block 702 with blister package arrays (e.g,., blister package array 102 on FIG. 4a) from a sterilization process which includes a step to evacuate a portion of the packaging solution from defective blister packages as described above. In block 704, the blister package arrays may be contacted against one or more force transducers, such as a load cell for example, to generate a signal corresponding to the measured force against one or more blister packs (e.g., blister package 401 on FIG. 4a) in the blister package array. In block 706 the force measured by from the force transducers may be compared to a nominal measurement to determine if the blister package may be defective. For blister packages without a packaging defect, the volume of the headspace at ambient temperature does not change from after the seal is applied through the sterilization cycle and the step to evacuate a portion of the packaging solution. The integrity of the seal (e.g., foil seal 408 on FIG. 4a) may be maintained throughout the sterilization process and thus the measured deflection of the seal in response to application of a force should remain relatively constant afterthe sterilization process. For blister packages with a defect, the headspace may change in volume when a portion of the packaging fluid is evacuated from the blister package during the sterilization cycle and / or the step to evacuate a portion of the packaging fluid. The change in head space volume results in an increased measured deflection of the foil seal in a defective blister pack. The force transducer may be used in a variety of ways to determine if the blister package may be defective. The force transducer may be brought into contact with the blister pack foil and the deflection of the foil may be measured over a period of time to determine if the measured deflection changes. The measured deflection may be compared to a nominal expected deflection over time for the package type and force applied through the transducer into the foil to determine if the measured deflection is greater than the nominal expected deflection. If the measured deflection is greater than the nominal expected deflection, the package may be deemed defective. Alternatively, the force transducer and foil may be brought into contact at a calibrated distance and the resulting measured force may be used to determine if the foil is deflecting more than an expected nominal amount. The foil deflection from the nominal amount may then be correlated to a defect in the packaging.

[0056] FIG. 8 illustrates an apparatus for implementing method 700 in FIG. 7. As shown in FIG. 8, tray 110 contains a plurality of blister package arrays 102. A force transducer body 802 is illustrated having a plurality of force transducers 804 operably disposed on fingers extending from the force transducer body. The fingers extend into the space between the plurality of blister package arrays 102 and the plurality of force transducers 804 contact the foil seal on one or more blister packs within the blister package array 102. The force measured by the plurality of force transducers 804 may then be correlated to a package condition and it may be determined if the package is defective.Additional Embodiments

[0057] Accordingly, the present disclosure may provide methods of detecting defects in contact lens packaging using a sterilization unit to evacuate a portion of a liquid within a contact lens packaging and detecting a change in volume of the liquid within the contact lens packaging. The methods may include any of the various features disclosed herein.

[0058] Embodiment 1. A method comprising: introducing a contact lens blister pack into a sterilizer unit, wherein the contact lens blister pack comprises a package base having a cavity, a contact lens disposed in the cavity, a packaging solution disposed in the cavity, and a film forminga seal over the cavity; controlling operating conditions of the sterilizer unit such that at least a portion of the packaging solution is evacuated from the contact lens blister pack if there is a defect in the contact lens blister pack; introducing the contact lens blister pack into a package integrity testing unit; and detecting whether the contact lens blister pack has a defect based at least on an amount of packaging solution remaining.

[0059] Embodiment 2. The method of embodiment 1 wherein controlling operating conditions of the sterilizer unit comprises: increasing pressure and temperature in the sterilizer unit from a first pressure and a first temperature to a second pressure and second temperature, wherein the first temperature and the second temperature are within a liquid phase region of a phase diagram of water, wherein the pressure and temperature in the sterilizer are increased while remaining within the liquid phase region of the phase diagram of water and avoiding entry into a gas phase region of the phase diagram of water; maintaining the second pressure and second temperature for a hold time; and decreasing the pressure in the sterilizer unit to a third pressure such that the temperature and pressure in the sterilizer unit are in the gas phase region of the phase diagram of water.

[0060] Embodiment 3. The method of any of embodiments 1-2 further comprising flashing a portion of the packaging solution to vapor.

[0061] Embodiment 4. The method of any of embodiments 1-3 wherein controlling operating conditions of the sterilizer unit comprises: increasing pressure and temperature in the sterilizer unit from a first pressure and a first temperature to a second pressure and second temperature, wherein the first temperature and the second temperature are within a liquid phase region of a phase diagram of water, wherein the pressure and temperature in the sterilizer are increased while remaining within the liquid phase region of the phase diagram of water and avoiding entry into a gas phase region of the phase diagram of water; maintaining the second pressure and second temperature for a hold time; and controlling a relative humidity of the sterilizer unit such that the relative humidity of the sterilizer unit is less than a relative humidity within a headspace of the contact lens blister pack.

[0062] Embodiment 5. The method of any of embodiments 1-4 further comprising evaporating at least a portion of the packaging solution.

[0063] Embodiment 6. The method of any of embodiments 1-5 wherein controlling operating conditions of the sterilizer unit comprises: increasing pressure in the sterilizer unit from a first pressure to a second higher pressure wherein the second pressure is higher than the first pressure;decreasing pressure in the sterilizer unit from the second pressure to a third pressure, wherein the third pressure is lower than the second pressure; increasing the pressure in the sterilizer unit from the third pressure to a fourth pressure, wherein the fourth pressure is higher than the third pressure; and decreasing the pressure in the sterilizer unit from the fourth pressure to a fifth pressure, wherein the fifth pressure is lower than the fourth pressure.

[0064] Embodiment 7. The method of any of embodiments 1-6 wherein a portion of the packaging solution is evacuated by at least one of decreasing pressure in the sterilizer unit from the second pressure to the third pressure and / or decreasing the pressure in the sterilizer unit from the fourth pressure to the fifth pressure.

[0065] Embodiment 8. The method of any of embodiments 1-7 wherein the package integrity testing unit comprises a heat source configured to heat the contact lens blister pack and a thermographic sensor configured to measure infrared radiation emitted from the blister pack.

[0066] Embodiment 9. The method of any of embodiments 1-8 wherein detecting the defect comprises identifying a bubble size of the packaging solution by correlating the measured infrared radiation emitted from the contact lens to the bubble size of the packaging solution, comparing the bubble size of the packaging solution to a nominal bubble size of the packaging solution, and determining if the bubble size of the packaging solution is smaller than the nominal bubble size of the packaging solution.

[0067] Embodiment 10. The method of any of embodiments 1-9 wherein detecting the defect comprises identifying a thermal signature of the blister pack by correlating the measured infrared radiation emitted from the contact lens to the thermal signature of the contact lens blister pack, comparing the thermal signature of the contact lens blister pack to a nominal thermal signature of the contact lens blister pack, and determining if the thermal signature of the contact lens blister pack corresponds to the nominal thermal signature of the contact lens blister pack.

[0068] Embodiment 11. The method of any of embodiments 1-10 wherein detecting the defect comprises identifying an average surface temperature of the contact lens blister pack by correlating the measured infrared radiation emitted from the contact lens blister pack to the average surface temperature of the contact lens blister pack, comparing the average surface temperature of the contact lens blister package to a nominal average surface temperature of the contact lens blister pack, and determining if the average surface temperature of the contact lens blister pack corresponds to the nominal average surface temperature of the contact lens blister pack.

[0069] Embodiment 12. The method of any of embodiments 1-11 wherein the package integrity unit comprises a mass balance and wherein detecting the defect comprises measuring a mass of the contact lens blister pack, comparing the mass of the contact lens blister pack to a nominal mass of the contact lens blister pack, and determining if the mass of the contact lens blister pack corresponds to the nominal mass of the contact lens blister pack.

[0070] Embodiment 13. The method of any of embodiments 1-12 wherein the package integrity unit comprises a force transducer and wherein detecting the defect comprises contacting the force transducer with the film.

[0071] Embodiment 14. The method of any of embodiments 1-14 wherein the package integrity unit comprises a force transducer and wherein detecting the defect comprises contacting the force transducer with the film, measuring a deflection of the film over time, comparing the deflection of the film over time to a nominal expected deflection over time, and determining if the measured deflection of the film over time corresponds to the nominal expected deflection over time and / or wherein the package integrity unit comprises a force transducer and wherein detecting the defect comprises contacting the force transducer with the film over a pre- determined distance, measuring a force using the force transducer, comparing the force to a nominal expected force, and determining if the measured force corresponds to the nominal expected force.

[0072] Embodiment 15. A method comprising: introducing a contact lens blister pack into a sterilizer unit, wherein the contact lens blister pack comprises a package base having a cavity, a contact lens and packaging solution disposed in the cavity, and a film forming a seal over the cavity, wherein the contact lens blister pack comprises a defect; controlling operating conditions of the sterilizer unit such at least a portion of the packaging solution is evacuated from the contact lens blister pack through the defect; and introducing the contact lens blister pack into a package integrity testing unit and detecting the defect.

[0073] Embodiment 16. The method of embodiment 15 wherein the package integrity testing unit comprises a heat source configured to heat the contact lens blister pack and a thermographic sensor configured to measure infrared radiation emitted from the contact lens blister pack, wherein detecting the defect comprises identifying a bubble size of the packaging solution by correlating the measured infrared radiation emitted from the contact lens to the bubble size of the packaging solution, comparing the bubble size of the packaging solution to a nominal bubble size of the packaging solution, and determining if the bubble size of the packaging solution is smaller thanthe nominal bubble size of the packaging solution, and / or wherein detecting the defect comprises identifying a thermal signature of the contact lens blister pack by correlating the measured infrared radiation emitted from the contact lens to the thermal signature of the contact lens blister pack, comparing the thermal signature of the contact lens blister pack to a nominal thermal signature of the contact lens blister pack, and determining if the thermal signature of the contact lens blister pack corresponds to the nominal thermal signature of the contact lens blister pack, and / or wherein detecting the defect comprises identifying an average surface temperature of the contact lens blister pack by correlating the measured infrared radiation emitted from the contact lens blister pack to the average surface temperature of the contact lens blister pack, comparing the average surface temperature of the contact lens blister package to a nominal average surface temperature of the contact lens blister pack, and determining if the average surface temperature of the contact lens blister pack corresponds to the nominal average surface temperature of the contact lens blister pack.

[0074] Embodiment 17. The method of any of embodiments 15-16 wherein the package integrity unit comprises a mass balance and wherein detecting the defect comprises measuring a mass of the contact lens blister pack, comparing the mass of the contact lens blister pack to a nominal mass of the contact lens blister pack, and determining if the mass of the contact lens blister pack corresponds to the nominal mass of the contact lens blister pack.

[0075] Embodiment 18. The method of any of embodiments 15-17 wherein the package integrity unit comprises a force transducer and wherein detecting the defect comprises contacting the force transducer with the film, measuring a deflection of the film over time, comparing the deflection of the film over time to a nominal expected deflection over time, and determining if the measured deflection of the film over time corresponds to the nominal expected deflection over time.

[0076] Embodiment 19. The method of any of embodiments 15-18 wherein the package integrity unit comprises a force transducer and wherein detecting the defect comprises contacting the force transducer with the film over a pre- determined distance, measuring a force using the force transducer, comparing the force to a nominal expected force, and determining if the measured force corresponds to the nominal expected force.

[0077] Embodiment 20. The method of any of embodiments 15-19 wherein the sterilizer unit and package integrity testing unit are components of a contact lens production line.

[0078] It is to be understood that the present disclosure is not limited to particular methods, which may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. All numbers and ranges disclosed herein may vary by some amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range are specifically disclosed. Although individual embodiments are discussed herein, the invention covers all combinations of all those embodiments. As used herein, the singular forms “a”, “an”, and “the” include singular and plural referents unless the content clearly dictates otherwise. Furthermore, the word “may” is used throughout this application in a permissive sense (i.e., having the potential to, being able to), not in a mandatory sense (i.e., must). The term' “include,” and derivations thereof, mean “including, but not limited to.” The term “coupled” means directly or indirectly connected. If there is any conflict in the usages of a word or term in this specification and one or more patent or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted for the purposes of understanding this invention.

[0079] For the sake of brevity, only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as, ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited. Additionally, whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range are specifically disclosed. In particular, every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a-b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values even if not explicitly recited. Thus, every point or individual value may serve as its own lower or upper limit combined with any other point or individual value or any other lower or upper limit, to recite a range not explicitly recited.

[0080] The scope of the present disclosure includes any feature or combination of features disclosed herein (either explicitly or implicitly), or any generalization thereof, whether or not it mitigates any or all of the problems addressed herein. Various advantages of the present disclosure 1have been described herein, but embodiments may provide some, all, or none of such advantages, or may provide other advantages.

Claims

What is claimed is:

1. A method comprising: introducing a contact lens blister pack into a sterilizer unit, wherein the contact lens blister pack comprises a package base having a cavity, a contact lens disposed in the cavity, a packaging solution disposed in the cavity, and a material forming a seal over the cavity; controlling operating conditions of the sterilizer unit such that at least a portion of the packaging solution is evacuated from the contact lens blister pack if there is a defect in the contact lens blister pack; introducing the contact lens blister pack into a package integrity testing unit; and detecting whether the contact lens blister pack has a defect based at least on an amount of packaging solution remaining.

2. The method of claim 1 wherein controlling operating conditions of the sterilizer unit comprises: increasing pressure and temperature in the sterilizer unit from a first pressure and a first temperature to a second pressure and second temperature, wherein the first temperature and the second temperature are within a liquid phase region of a phase diagram of water, wherein the pressure and temperature in the sterilizer are increased while remaining within the liquid phase region of the phase diagram of water and avoiding entry into a gas phase region of the phase diagram of water; maintaining the second pressure and second temperature for a hold time; and decreasing the pressure in the sterilizer unit to a third pressure such that the temperature and pressure in the sterilizer unit are in the gas phase region of the phase diagram of water.

3. The method of claim 2 further comprising flashing a portion of the packaging solution to vapor.

4. The method of claim 1 wherein controlling operating conditions of the sterilizer unit comprises: increasing pressure and temperature in the sterilizer unit from a first pressure and a first temperature to a second pressure and second temperature, wherein the first temperature and the second temperature are within a liquid phase region of a phase diagram of water, wherein the pressure and temperature in the sterilizer are increased while remaining within the liquid phaseregion of the phase diagram of water and avoiding entry into a gas phase region of the phase diagram of water; maintaining the second pressure and second temperature for a hold time; and controlling a relative humidity of the sterilizer unit such that the relative humidity of the sterilizer unit is less than a relative humidity within a headspace of the contact lens blister pack.

5. The method of claim 4 further comprising evaporating at least a portion of the packaging solution.

6. The method of claim 1 wherein controlling operating conditions of the sterilizer unit comprises: increasing pressure in the sterilizer unit from a first pressure to a second pressure wherein the second pressure is higher than the first pressure; decreasing pressure in the sterilizer unit from the second pressure to a third pressure, wherein the third pressure is lower than the second pressure; increasing the pressure in the sterilizer unit from the third pressure to a fourth pressure, wherein the fourth pressure is higher than the third pressure; and decreasing the pressure in the sterilizer unit from the fourth pressure to a fifth pressure, wherein the fifth pressure is lower than the fourth pressure.

7. The method of claim 6 wherein a portion of the packaging solution is evacuated by at least one of decreasing pressure in the sterilizer unit from the second pressure to the third pressure and / or decreasing the pressure in the sterilizer unit from the fourth pressure to the fifth pressure.

8. The method of claim 1 wherein the package integrity testing unit comprises a heat source configured to heat the contact lens blister pack and a thermographic sensor configured to measure infrared radiation emitted from the blister pack.

9. The method of claim 1 wherein detecting the defect comprises identifying a bubble size of the packaging solution by correlating a measured infrared radiation emitted from the contact lens to the bubble size of the packaging solution, comparing the bubble size of the packaging solution toa nominal bubble size of the packaging solution, and determining if the bubble size of the packaging solution is smaller than the nominal bubble size of the packaging solution.

10. The method of claim 1 wherein detecting the defect comprises identifying a thermal signature of the blister pack by correlating a measured infrared radiation emitted from the contact lens to a thermal signature of the contact lens blister pack, comparing the thermal signature of the contact lens blister pack to a nominal thermal signature of the contact lens blister pack, and determining if the thermal signature of the contact lens blister pack corresponds to the nominal thermal signature of the contact lens blister pack.

11. The method of claim 1 wherein detecting the defect comprises identifying an average surface temperature of the contact lens blister pack by correlating a measured infrared radiation emitted from the contact lens blister pack to an average surface temperature of the contact lens blister pack, comparing the average surface temperature of the contact lens blister pack to a nominal average surface temperature of the contact lens blister pack, and determining if the average surface temperature of the contact lens blister pack corresponds to the nominal average surface temperature of the contact lens blister pack.

12. The method of claim 1 wherein the package integrity testing unit comprises a mass balance and wherein detecting the defect comprises measuring a mass of the contact lens blister pack, comparing the mass of the contact lens blister pack to a nominal mass of the contact lens blister pack, and determining if the mass of the contact lens blister pack corresponds to the nominal mass of the contact lens blister pack.

13. The method of claim 1 wherein the package integrity testing unit comprises a force transducer and wherein detecting the defect comprises contacting the force transducer with the material forming the seal.

14. The method of claim 1 wherein the package integrity testing unit comprises a force transducer and wherein detecting the defect comprises contacting the force transducer with the material forming the seal, measuring a deflection of the material over time, comparing the deflection of thematerial over time to a nominal expected deflection over time, and determining if the measured deflection of the material over time corresponds to the nominal expected deflection over time and / or wherein detecting the defect comprises contacting the force transducer with the material forming the seal over a pre-determined distance, measuring a force using the force transducer, comparing the force to a nominal expected force, and determining if the measured force corresponds to the nominal expected force.

15. The method of claim 1 where the material forming a seal over the cavity is a multi-layer film.

16. The method of claim 1 where the material forming a seal over the cavity is a multi-layer film comprising at least a foil layer and a sealing layer.

17. A method comprising: introducing a contact lens blister pack into a sterilizer unit, wherein the contact lens blister pack comprises a package base having a cavity, a contact lens and packaging solution disposed in the cavity, and a material forming a seal over the cavity, wherein the contact lens blister pack comprises a defect; controlling operating conditions of the sterilizer unit such at least a portion of the packaging solution is evacuated from the contact lens blister pack through the defect; and introducing the contact lens blister pack into a package integrity testing unit and detecting the defect.

18. The method of claim 17 wherein the package integrity testing unit comprises a heat source configured to heat the contact lens blister pack and a thermographic sensor configured to measure infrared radiation emitted from the contact lens blister pack, wherein detecting the defect comprises identifying a bubble size of the packaging solution by correlating the measured infrared radiation emitted from the contact lens to the bubble size of the packaging solution, comparing the bubble size of the packaging solution to a nominal bubble size of the packaging solution, and determining if the bubble size of the packaging solution is smaller than the nominal bubble size of the packaging solution, and / orwherein detecting the defect comprises identifying a thermal signature of the contact lens blister pack by correlating the measured infrared radiation emitted from the contact lens to the thermal signature of the contact lens blister pack, comparing the thermal signature of the contact lens blister pack to a nominal thermal signature of the contact lens blister pack, and determining if the thermal signature of the contact lens blister pack corresponds to the nominal thermal signature of the contact lens blister pack, and / or wherein detecting the defect comprises identifying an average surface temperature of the contact lens blister pack by correlating the measured infrared radiation emitted from the contact lens blister pack to the average surface temperature of the contact lens blister pack, comparing the average surface temperature of the contact lens blister pack to a nominal average surface temperature of the contact lens blister pack, and determining if the average surface temperature of the contact lens blister pack corresponds to the nominal average surface temperature of the contact lens blister pack.

19. The method of claim 17 wherein the package integrity testing unit comprises a mass balance and wherein detecting the defect comprises measuring a mass of the contact lens blister pack, comparing the mass of the contact lens blister pack to a nominal mass of the contact lens blister pack, and determining if the mass of the contact lens blister pack corresponds to the nominal mass of the contact lens blister pack.

20. The method of claim 17 wherein the package integrity testing unit comprises a force transducer and wherein detecting the defect comprises contacting the force transducer with the material forming the seal, measuring a deflection of the material over time, comparing the deflection of the material over time to a nominal expected deflection over time, and determining if the measured deflection of the material over time corresponds to the nominal expected deflection over time.

21. The method of claim 17 wherein the package integrity testing unit comprises a force transducer and wherein detecting the defect comprises contacting the force transducer with the material forming the seal over a pre-determined distance, measuring a force using the force transducer, comparing the force to a nominal expected force, and determining if the measured force corresponds to the nominal expected force.

22. The method of claim 17 wherein the sterilizer unit and package integrity testing unit are components of a contact lens production line.

23. The method of claim 17 where the material forming a seal over the cavity is a multi-layer film.

24. The method of claim 17 where the material forming a seal over the cavity is a multi-layer film comprising at least a foil layer and a sealing layer.

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