Systems and methods for priming a microfluidic chamber

An intraocular device for implantation in an eye of a patient is provided. The intraocular device includes an inlet tube, an outlet tube, and a microfluidic chamber. The microfluidic chamber includes a chamber inlet coupled to the inlet tube, a chamber outlet coupled to the outlet tube, and one or more fluidic barriers. Each fluidic barrier is configured such that, as a fluid is injected into the microfluidic chamber, a front of the fluid coincides with the fluidic barrier before any of the fluid passes beyond the fluidic barrier. Associated methods are also disclosed herein.

BACKGROUND

The present disclosure relates generally to purging a gas from a microfluidic chamber. An example of such a microfluidic chamber may be presented by pressure measurement systems for use in ophthalmic treatments.

Glaucoma, a group of eye diseases affecting the retina and optic nerve, is one of the leading causes of blindness worldwide. Most forms of glaucoma result when the intraocular pressure (IOP) increases to pressures above normal for prolonged periods of time. IOP can increase due to high resistance to the drainage of the aqueous humor relative to its production. Left untreated, an elevated IOP causes irreversible damage to the optic nerve and retinal fibers resulting in a progressive, permanent loss of vision.

The eye's ciliary body continuously produces aqueous humor, the clear fluid that fills the anterior segment of the eye (the space between the cornea and lens). The aqueous humor flows out of the anterior chamber (the space between the cornea and iris) through the trabecular meshwork and the uveoscleral pathways, both of which contribute to the aqueous humor drainage system. The delicate balance between the production and drainage of aqueous humor determines the eye's IOP.

FIG. 1is a diagram of the front portion of an eye100that helps to explain the processes of glaucoma. InFIG. 1, representations of the lens110, cornea120, iris130, ciliary body140, trabecular meshwork150, Schlemm's canal160, and the edges of the sclera170are pictured. Anatomically, the anterior segment of the eye includes the structures that cause elevated IOP which may lead to glaucoma. Aqueous humor fluid is produced by the ciliary body140that lies beneath the iris130and adjacent to the lens110in the anterior segment of the eye. This aqueous humor washes over the lens110and iris130and flows to the drainage system located in the angle of the anterior chamber180. The edge of the anterior chamber, which extends circumferentially around the eye, contains structures that allow the aqueous humor to drain. The trabecular meshwork150is commonly implicated in glaucoma. The trabecular meshwork150extends circumferentially around the anterior chamber. The trabecular meshwork150seems to act as a filter, limiting the outflow of aqueous humor and providing a back pressure that directly relates to IOP. Schlemm's canal160is located beyond the trabecular meshwork150. Schlemm's canal160is fluidically coupled to collector channels (not shown) allowing aqueous humor to flow out of the anterior chamber. The sclera170, the white of the eye, connects to the cornea120, forming the outer, structural layer of the eye. The two arrows in the anterior segment ofFIG. 1show the flow of aqueous humor from the ciliary bodies140, over the lens110, over the iris130, through the trabecular meshwork150, and into Schlemm's canal160and out its collector channels.

As part of a method for treating glaucoma, a doctor may implant a device in a patient's eye. The device may monitor the pressure in a patient's eye and facilitate control of that pressure by allowing excess aqueous humor to flow from the anterior chamber of the eye to a drainage site, relieving pressure in the eye and thus lowering IOP. To exert appropriate control, an accurate measurement of the pressure about the patient's eye may be made. In order to accurately measure pressure, one or more chambers may require priming. However, the priming of chambers of the size required for implantation into a patient's eye has not been entirely satisfactory.

The system and methods disclosed herein overcome one or more of the deficiencies of the prior art.

SUMMARY

In one exemplary aspect, the present disclosure is directed to an intraocular device for implantation in an eye of a patient. The intraocular device includes an inlet tube and an outlet tube coupled to a chamber inlet and a chamber outlet, respectively, of a microfluidic chamber. The chamber includes one or more fluidic barriers configured such that when a fluid is injected into the chamber, a front of the fluid coincides with each of the one or more fluidic barriers before any of the fluid passes beyond the fluidic barrier.

In yet another exemplary aspect, the present disclosure is directed to a method of forming a microfluidic chamber for use in an intraocular device. The method may include steps of providing a substrate, forming a bottom surface within the substrate, and forming a chamber inlet and a chamber outlet with both the chamber inlet and the chamber outlet in communication with the bottom surface. The method may further include fixing an additional substrate to the substrate. The additional substrate may have at least one fluidic barrier formed thereon such that when a fluid enters the chamber, a front of the fluid coincides with the fluidic barrier before passing beyond the at least one fluidic barrier.

In another exemplary aspect, the present disclosure is directed to a method of priming a chamber in an intraocular device. The method may include steps of coupling a liquid source to an inlet of a chamber in the intraocular device, in which the chamber including at least one barrier that provides resistance to a liquid, and injecting a first portion of the liquid through the inlet into the chamber, such that a front of the liquid coincides with the at least one barrier. The method may further include continuing to inject the liquid such that the liquid passes the at least one barrier and exits the chamber through an outlet thereof.

It is to be understood that both the foregoing general description and the following drawings and 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

The present disclosure relates generally to a system and method for ensuring gas bubbles are fully purged from a microfluidic chamber by guiding the liquid or fluid during the priming of the chamber. The chamber may be used in connection with a pressure sensor in an intraocular device, such as a glaucoma drainage device (GDD). GDDs are used to alleviate excess pressure caused by aqueous humor accumulation in a patient's eye. A gas bubble may adversely affect the measurements made by a pressure sensor in the GDD.

The intraocular device may include an inlet and an outlet leading to and from the chamber. The chamber includes at least one fluidic barrier that inhibits the flow of a liquid beyond the barrier, such that a front of the liquid coincides with the full length of the barrier before any of the liquid passes beyond the barrier. In this manner, the liquid may flow through the chamber in a way that decreases or eliminates the formation of gas bubbles within the chamber. The systems and methods disclosed herein may thereby enable more accurate measurements in the chamber by reducing the likelihood of air bubbles, resulting in better treatment planning, potentially providing more effective treatment and greater customer satisfaction.

FIG. 2is a view of an intraocular implant or device200such as may be used in the monitoring and treatment of a patient's eye. As depicted, the intraocular device200is a GDD. The intraocular device200includes a body referred to herein as a plate210with a drainage tube220that extends from the plate210. The drainage tube220includes a proximal end portion222that couples the tube to one or more structures internal to the plate210. A distal end portion224of the drainage tube220may be coupled to the eye of a patient to allow for the monitoring of pressure and/or the drainage of fluid. As depicted, the intraocular device200includes two additional tubes: an inlet tube230and an outlet tube240, which may be ligated prior to implantation. The inlet tube230and outlet tube240may provide access to a chamber on the plate210that forms part of a passive valve system. This chamber will be discussed in greater detail below.

FIG. 3is a view of an eye of a patient whose IOP is being monitored and/or who is receiving treatment with the intraocular device200. The plate210may include or be arranged to carry various components of an IOP control system (not shown). In some embodiments, such components include a power source, a processor, a memory, a data transmission module, and a flow control mechanism (i.e. valve system). It may also carry one or more pressure sensor systems.

The plate210is configured to fit at least partially within the subconjunctival space and is sized within a range between about 15 mm×12 mm to about 30 mm×15 mm and has a thickness less than about 2 mm thick, preferably less than about 1 mm thick. The plate210may be formed to the radius of the eye globe (about 0.5 inches). It may be rigid and preformed with a curvature suitable to substantially conform to the globe or it may be flexible and can flex to conform to the globe. Some embodiments are small enough that conforming to the globe provides little benefit in comfort or implantation technique. The above dimensions are exemplary only, and other sizes and arrangements are contemplated herein.

In some embodiments, the drainage tube220extends from an anterior side of the plate210and is sized and arranged to extend into the anterior chamber of the eye through a surgically formed opening312in the sclera. The drainage tube220may be used to measure pressure in addition to facilitating drainage. The drainage tube220includes a first open end that may be disposed at a location where pressure measurements may be desired, and at least one lumen that extends to a second open end that may be disposed within or connected to the plate210.

Prior to placement around a patient's eye as depicted inFIG. 3, a chamber within the plate210may be primed by the injection of liquid that displaces a gas from the chamber. The liquid may be injected through the inlet tube230until some liquid may exit through the outlet tube240. After the air is satisfactorily purged from the chamber, one or more tubes may be ligated as discussed above, and the intraocular device200is implanted.

FIG. 4Ais a top-view view of a microfluidic chamber400such as may be present in the intraocular implant200ofFIG. 2. The chamber400includes a chamber inlet410disposed on one side and a chamber outlet420disposed opposite the inlet410. However, in some embodiments, the inlet410and the outlet420may not be disposed opposite each other with respect to the volume of the chamber400. When the chamber400is primed, liquid enters through the inlet410and displaces air out through the outlet420.

At times, when liquid is introduced into a microfluidic chamber the liquid may begin to exit the chamber before all the gas therein is expelled, leaving behind one or more bubbles. These bubbles may prevent desired operation of valves or other components, and may result in decreased accuracy for measurements such as pressure readings. To inhibit the formation of gas bubbles within chamber400, chamber400includes one or more fluidic barriers. As depicted, chamber400includes three such barriers: barriers430A,430B, and430C. The barriers430A-C may be straight or curved. As depicted, barrier430A is straight or nearly straight, while both barriers430B and430C are curved. In some embodiments, all the barriers may be curved. The barriers430A-C may be symmetric about an axis running from the inlet410to the outlet420, depicted as line A-A. The radii of curvature of barriers430A-C may decrease with proximity to the outlet420. Thus, as depicted inFIG. 4A, barrier430C has a lower radius of curvature than barrier430B, which has a lower radius of curvature than barrier430A.

FIG. 4Bis a cross-sectional view of the microfluidic chamber ofFIG. 4Aas viewed along line A-A. As seen in cross-section, chamber400includes a bottom surface440and a top surface450. In some embodiments, a distance between the bottom surface440and the top surface450within the chamber400may range from around 200 to around 500 microns. For example, in some embodiments the distance may be around 400 microns. As seen in the cross-section ofFIG. 4B, the barriers430A-C are structures that protrude or extend from the top surface450toward the bottom surface440. Given the scale of the chamber400, the orientation of the chamber400is not critical. Accordingly, the designations “top” surface450and “bottom” surface440are arbitrary and should be understood as helping to describe a relationship of one surface to the other. As depicted, bottom surface440is circular, but other embodiments may be elliptical or have another shape.

The protrusions of barriers430A-C may be rectangular, triangular, trapezoidal, or curved in cross-sectional shape. The protrusions of barriers430A-C extend into the chamber400by around 50 microns. The appropriate protrusion height depends on the surface tension characteristics of the priming liquid as well as the dimension of the chamber, and may range from 10 to 100 microns. Due to the microfluidic conditions within the chamber400, as a liquid flows from the inlet410to the outlet420, the front of the liquid remains in contact with both the top surface450and the bottom surface440. The front of the liquid is the leading surface of the liquid as it is introduced into the chamber400and flows through it to the outlet420. When the front of the liquid comes into contact with one of the barriers430A-C, such as barrier430A, the front of the liquid may not pass beyond the barrier until it first coincides with the full length of the barrier. Once the liquid front can no longer expand laterally along the barrier it then passes that barrier, as will be discussed in greater detail below.

FIG. 4Cis an additional, fragmentary cross-sectional view of the microfluidic chamber400ofFIG. 4Aas viewed along the line A-A.FIG. 4Bmay provide additional details regarding the construction or fabrication of the chamber400. In some embodiments, the bottom portion of the chamber400, including the bottom surface440, is fabricated in a substrate460, only a portion of which is shown. Embodiments of the substrate460may be made from a variety of materials including glass, silicon, polyetheretherketone (PEEK), or other material. The substrate460may be machined or etched to form the bottom portion of chamber400. The substrate460may have many other features that are not depicted inFIG. 4C, such as additional microfluidic structures and channels, sensors, and associated controllers and circuitry.

The top surface450of the chamber400may be formed in an additional substrate470, which may be made of the same materials as the substrate460. Only a portion of the additional substrate470is depicted inFIG. 4C. The additional substrate470may be etched or machined to produce the protruding barriers430A-C and top surface450. After the formation of the bottom surface440and the top surface450, the substrates460and470may be fixed together. This fixation may be provided by a bonding or adhesion process.

Some embodiments of the chamber400may include a different type of barrier rather than the barriers430A-C as depicted. For example, rather than being provided by protrusions, the fluidic barriers may be slots or recesses produced by removal of material, by etching, machining, or other appropriate process, such that the top view is as depicted inFIG. 4A. In such embodiments, corresponding cross-sectional views may depict recessed barriers430A-C, rather than protruding barriers430A-C.

FIGS. 5A,5B,5C,5D, and5E are top-view views showing the microfluidic chamber400ofFIGS. 4A-4Cin various stages of priming. Each of theFIGS. 5A-Edepicts a liquid500as it enters through the inlet410and exits through the outlet420. While any purging liquid may be used, some embodiments employ a saline solution. As depicted inFIG. 5A, the liquid500has passed through the inlet410entering into the chamber400. As the volume of liquid500within the chamber400increases, a front510of the liquid progresses toward barrier430A.

When a portion of the front510contacts the barrier430A, the far side of the barrier430A may inhibit the progress of the front510. The resistance to the liquid front510provided by the barrier430A directs an additional volume of liquid500laterally along the barrier430A as it is injected until the front510coincides with the barrier430A, as depicted inFIG. 5B. The resistance provided by the barrier430A may not be overcome until all the space between the inlet410and the barrier430A is filled.

When the front510and the barrier430A coincide, additional liquid500causes the front510to flow beyond the barrier430A. This additional liquid500begins to fill the space defined between the barrier430A and the barrier430B. When the front510encounters the barrier430B, the barrier430B provides resistance to the front510such that additional liquid is directed along the barrier430B as more liquid is injected. When the front510coincides with the barrier430B, as depicted inFIG. 5C, additional liquid500may overcome the resistance and pass beyond the barrier430B. Similarly, the space between the barrier430C and the barrier430B may fill (as depicted inFIG. 5D) before any liquid500passes beyond the barrier430C. When a sufficient volume of liquid500is injected through the inlet410into the chamber400, the liquid500passes beyond each of the barrier430A-C and exits through the outlet420. Thus, as liquid500is continuously injected into the inlet410, the barrier430A may cause the volume defined between it and the inlet410to fill, and then barrier430B may cause the volume defined between it and the barrier430A to fill, before any of the liquid500exits through the outlet420as depicted inFIG. 5E.

Some embodiments of the chamber400include more or fewer than the three barriers430A-C depicted inFIGS. 4A-Cand5A-D. In such embodiments, the passage of the liquid500from the inlet410to the outlet420may be substantially as described above. Additionally, in embodiments in which the barriers430A-C are recesses, rather than protrusion, a similar process may occur. However, in such recessed barrier embodiments the resistance to the front510may be provided at a lip present at a near side of each barrier. In general, the barriers430A-C guide the front510of the liquid500to the sides of the chamber400to prevent the formation of bubbles along the sides thereof.

FIG. 6Ais a top-view view of a microfluidic chamber600as may be used in the intraocular implant200. The microfluidic chamber600shares many features of the chamber400described above. Thus, an inlet610is configured to permit fluid to enter into the microfluidic chamber600, while an outlet620allows fluid to exit the chamber600. To help prevent the formation of bubbles along the sides of the chamber600, a plurality of microfluidic barriers may be present therein. As depicted, three barriers are present, including barriers630A,630B, and630C. Some embodiments of the chamber600may include more or fewer barriers than depicted inFIG. 6A. Unlike the barriers430A-C, barriers630A-C may not protrude from or recess into a top surface of chamber600. Instead, a surface treatment may be applied to the area of barriers630A-C to alter their hydrophobicity relative to the rest of the top surface of chamber600. For example, barriers630A-C may be hydrophobic areas relative to the rest of the top surface of the chamber600. As in the chamber400, embodiments of the chamber600may include barriers430A-C having significantly different radii of curvature.

FIG. 6Bis a cross-sectional view of the microfluidic chamber600ofFIG. 6Aas seen along line B-B. This perspective may be helpful in understanding how a top surface650of the chamber600provides the barriers630A-C. A lower substrate may be shaped to form the bottom surface640, while an upper substrate may be shaped to form the top surface650. In general, the bottom surface640and the top surface650may be hydrophilic surfaces. In such embodiments, the barriers630A-C may be made hydrophobic by chemical or mechanical treatment applied to areas the top surface650corresponding to the barriers. The operation of the chamber600may be similar to the chamber400as depicted inFIGS. 5A-E. Thus, the progress of a liquid front moving from the inlet610to the outlet620may encounter resistance where the top surface650changes from a hydrophilic surface to the relatively hydrophobic surface of one of barriers630A-C. This resistance may direct the liquid laterally to the sides of the chamber600, causing an area behind the barrier to fill with liquid, before the front of the liquid passes the barrier.

FIG. 7Ais a top-view view of a microfluidic chamber700such as may be used in an intraocular implant. Like chambers400and600, the chamber700may guide a fluid in such a way as to prevent the formation of bubbles along the sides of the chamber. Chamber700includes an inlet710and an outlet720that allow a liquid to enter and exit the chamber. Also like chambers400and600discussed above, chamber700includes one or more barriers that may guide injected fluid laterally toward the sides and along the barrier before the fluid front moves beyond the barrier. Chamber700includes a plurality of shelf-type barriers730A and730B. As depicted, each of the barriers730A and730B is curved, however in some embodiments one or more may be straight as seen from above. The barriers730A-B may be better understood by reference toFIG. 7B.

FIG. 7Bis a fragmentary, cross-sectional view of the microfluidic chamber700ofFIG. 7Aas seen along a line C-C ofFIG. 7A. As depicted inFIG. 7B, the microfluidic chamber700includes an inlet710at a first level, the first level being defined by a height of the chamber700. The barrier730A is formed by a change in the height of the chamber700. In some embodiments, like that depicted, the change in height is an increase in the height. Thus, barrier730A may be provided by a change in height within chamber700. This change may be from about 10 microns to about 100 microns. In some embodiments, a change in height of the chamber700that is about 50 microns may be used to form barrier730A. An additional change of height within the chamber700may provide barrier730B. The changes in height may be produced by machining or etching a bottom substrate740and a top substrate750(a portion of both being depicted) and then fixing them together in alignment. Embodiments of the chamber700may include more or fewer barriers than depicted. In some embodiments, the inlet710and the outlet720may be coplanar. The operation of the chamber700may be better understood by reference toFIGS. 8A-H.

FIGS. 8A and 8B,8C and8D,8E and8F, and8G and8H are pairs of fragmentary cross-sectional and top-view views showing the microfluidic chamber700in various stages of priming with a liquid800. InFIGS. 8A and 8B, the liquid800is injected through the inlet710and enters into the chamber700. A front810of the liquid800is seen approaching the barrier730A. When part of the front810comes into contact with the barrier730A, the resistance provided by the barrier730A may inhibit the front810from passing the barrier. Instead, the barrier730A may direct the liquid800to the sides of the chamber700. When the liquid front810coincides with the barrier730A, as depicted inFIGS. 8C and 8D, then the resistance provided by the barrier may be overcome by the continually injected liquid800. The front810may then pass beyond barrier730A.

As more liquid800is injected through the inlet710into the chamber700, a portion of the front810encounters resistance at the barrier730B, such that the liquid800is redirected laterally until the front810coincides with the barrier730B along its entire length. This is depicted inFIGS. 8E and 8F. As liquid800is continuously injected, the front810overcomes the resistance and moves beyond the barrier730B. In embodiments having more barriers, a similar process may occur at each barrier as the volume of liquid800injected into the chamber700increases. After a sufficient volume of liquid800has been injected to fill the chamber700, the front810moves out of the chamber700and through the outlet720, as depicted inFIGS. 8G and 8H. The resistance applied by the barriers730A and730B to the front810may force liquid800to the sides of chamber700so as to remove bubbles and/or prevent their formation.

FIG. 9is a flowchart of a method900of priming a microfluidic chamber according to an exemplary aspect of the present disclosure. Method900includes a plurality of enumerated steps, but embodiments of method900may further include additional steps before, in between, and after the enumerated steps. Method900may begin at step902in which a liquid source is coupled to an inlet of a chamber in an intraocular device. The chamber includes at least one barrier that provides resistance to a liquid. At step904, a first portion of the liquid is injected through the inlet into the chamber. As the liquid is injected into the chamber, the first portion of the liquid may expand until a front of the first portion coincides with the at least one barrier. At step906, the injection of liquid may continue such that the liquid and the front thereof passes the barrier and exits the chamber through an outlet.

In order to better describe the method900, reference will now be made to chamber700as depicted inFIGS. 7A-Band8A-G. Method900may also be performed with other chambers, such as chamber400and chamber600as described above. At step902, prior to implantation next to a patient's eye, a doctor or technician may couple a liquid source such as a syringe to a tube coupled to the inlet710. The doctor may use the syringe to inject the liquid800into the inlet710and thereby into the chamber700. At step904, while injecting the liquid800, the doctor may inject a first portion of the liquid through the inlet710until the front810of liquid800coincides with the barrier730A. As the doctor continues to inject the liquid800, the front810passes beyond the barrier730A and begins to fill a volume that may be defined between the barrier730A and the barrier730B. Once the front810coincides with the barrier730B, as the doctor continues to inject the liquid800the front810moves beyond the barrier730B. At step906, when a sufficient amount of liquid800is injected through the inlet710to fill the chamber700, as the doctor continues to inject the liquid800the front810exits the chamber and moves through the outlet720.

In this manner, method900may prevent or decrease the incidence of bubble formation and trapping within the chamber700. As the liquid800continuously enters the chamber700, it fills a first discrete portion thereof defined by the barriers present within the chamber before it fills a second discrete portion, and so on as the case may be, and then exits the chamber. As liquid800exits the chamber700through the outlet720, it may pass through an outlet tube coupled to the outlet of the chamber. The doctor or technician may understand from the liquid800exiting the outlet tube that the chamber700is primed, and thereafter may ligate the inlet tube, the outlet tube, or both. In some instances, neither the inlet tube nor the outlet tube is ligated.

FIG. 10is a flowchart of a method1000of forming a microfluidic chamber according to many embodiments of the disclosure. In other words, the method1000may be performed to form the microfluidic chambers400,600, and/or700as described and depicted herein. Embodiments of the method1000may include additional steps before, in between, and/or after the enumerated steps of the method. As depicted inFIG. 10, the method1000may begin at step1002in which a substrate is provided. A bottom surface is formed within the substrate, at step1004. Additionally, a chamber inlet and a chamber outlet are formed in the substrate, at step1006. At step1008, an additional substrate having at least one fluidic barrier thereon is fixed to the substrate.

As discussed above, the method1000may be performed to form embodiments of the microfluidic chambers400,600, and/or700. In order to better describe the method1000, reference will be made to the microfluidic chamber400as depicted inFIGS. 4A-Cand described in corresponding sections above. InFIG. 4C, a substrate460is depicted after some patterning. At step1002, this substrate460may be provided as a blank, planar substrate prepared for patterning by chemical and/or mechanical processing. As discussed above, the substrate460may be a plastic substrate, such as PEEK, or a ceramic substrate, such as glass or silicon.

At step1004, the substrate460may be patterned by an etching process to form the bottom surface440of the chamber. At step1006, either by the same patterning process, or an earlier or later process, the inlet410and the outlet420are formed. An additional substrate470is also provided. The additional substrate470may be patterned by an appropriate process to form one or more fluidic barriers. At step1008, the substrate460and the additional substrate470are then fixed together by a bonding or adhesive process, or other such suitable process. In order to incorporate the chamber400into an intraocular device, an inlet tube may be coupled to the inlet410and an outlet tube may be coupled to the outlet420.

In some embodiments of the method1000, the bottom surface and the inlet and outlet may be formed such that they may be removed after the additional substrate is fixed to the substrate. For example, using semiconductor processing technology, such as those used in complementary metal-oxide-silicon (CMOS) and microelectromechanical system (MEMS) fabrication, the bottom surface, inlet, and outlet may be presented when a top layer is deposited as the additional substrate470. After the deposition of the additional substrate470, material defining the bottom surface, inlet, and outlet may be removed by an etchant to form the corresponding structures.

In forming the one or more fluidic barriers on the additional substrate, any of the barriers described above, such as protruding barriers, recessed barriers, hydrophobicity-based barriers, or shelf-type barriers, may be used in various embodiments. In some embodiments, combinations of these and other types of fluidic barriers may be used. Additionally, some features described above as being formed in the additional substrate may be formed in the bottom substrate, and similarly some features described above as being formed in the substrate may be formed in the additional substrate. For example, a microfluidic chamber may be formed in which the inlet and the outlet are formed in the substrate that is processed to provide the top surface of the chamber. In other embodiments, portions of the inlet and the outlet may be formed in both the additional substrate and the bottom substrate. The arrangement of the fluidic barriers may also vary in different embodiments. For example, some or all of the barriers may be formed on the bottom surface. In such embodiments, the process of priming the chamber formed in such a manner may be substantially similar as the processes described above and depicted inFIGS. 5A-Eand8A-G.

The systems and methods disclosed herein may be used to provide better performance for intraocular devices, such as increased accuracy in pressure measurements. This may be done by guiding a front of an injected liquid toward the sides of a chamber before the liquid progresses closer to the chamber exit. This may result in more effective treatment and more accurate data, thereby improving the overall clinical result.

Persons of ordinary skill in the art will appreciate that the embodiments encompassed by the present disclosure are not limited to the particular exemplary embodiments described above. In that regard, although illustrative embodiments have been shown and described, a wide range of modification, change, and substitution is contemplated in the foregoing disclosure. It is understood that such variations may be made to the foregoing without departing from the scope of the present disclosure. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the present disclosure.