Abstract:
An intraocular shunt deployment device can release an intraocular shunt into an eye using a deployment mechanism that coordinates action between a pusher component, a shaft component, and a housing of the device. The deployment mechanism causes axial movement of the components in response to a rotational input force.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 12/946,645, filed on Nov. 15, 2010, the entirety of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     The invention generally relates to devices for deploying an intraocular shunt within an eye. 
     2. Description of the Related Art 
     Glaucoma is a disease of the eye that affects millions of people. Glaucoma is associated with an increase in intraocular pressure resulting either from a failure of a drainage system of an eye to adequately remove aqueous humor from an anterior chamber of the eye or overproduction of aqueous humor by a ciliary body in the eye. Build-up of aqueous humor and resulting intraocular pressure may result in irreversible damage to the optic nerve and the retina, which may lead to irreversible retinal damage and blindness. 
     Glaucoma may be treated by surgical intervention that involves placing a shunt in the eye to result in production of fluid flow pathways between the anterior chamber and various structures of the eye involved in aqueous humor drainage (e.g., Schlemm&#39;s canal, the sclera, or the subconjunctival space). Such fluid flow pathways allow for aqueous humor to exit the anterior chamber. Generally, the surgical intervention to implant the shunt involves inserting into the eye a deployment device that holds an intraocular shunt, and deploying the shunt within the eye. A deployment device holding the shunt enters the eye through a cornea (ab interno approach), and is advanced across the anterior chamber. The deployment device is advanced through the sclera until a distal portion of the device is in proximity to a drainage structure of the eye. The shunt is then deployed from the deployment device, producing a conduit between the anterior chamber and various structures of the eye involved in aqueous humor drainage (e.g., Schlemm&#39;s canal, the sclera, or the subconjunctival space). See for example, Prywes (U.S. Pat. No. 6,007,511). 
     A problem associated with such surgical interventions is ensuring that placement of the shunt does not change during deployment of the shunt from the deployment device. Deployment devices that are used to place the shunt in the eye generally rely on multiple moving components in order to deploy the shunt. Movement of the components of the deployment device shifts the position of the deployment device within the eye during the deployment process, and thus shifts the position of the shunt as it is being deployed. Such movement leads to improper placement of the shunt within the eye. 
     SUMMARY 
     The invention generally relates to deployment devices that are designed to minimize movement of the device during deployment of an intraocular shunt from the device, thereby ensuring proper placement of the shunt within the eye. 
     In certain aspects, deployment devices of the invention include a housing, a deployment mechanism at least partially disposed within the housing, and a hollow shaft coupled to the deployment mechanism, in which the shaft is configured to hold an intraocular shunt. With such devices, rotation of the deployment mechanism results in deployment of the shunt. Such rotational movement is translated into axial movement for deploying the shunt from the device. By utilizing rotational movement for the deployment mechanism, axial movement of the deployment device is minimized, ensuring proper placement of the shunt within the eye. 
     Other aspects of the invention provide devices for deploying an intraocular shunt including a housing, a deployment mechanism at least partially disposed within the housing, in which the deployment mechanism includes a two stage system, and a hollow shaft coupled to the deployment mechanism, in which the shaft is configured to hold an intraocular shunt. 
     Another aspect of the invention includes devices for deploying an intraocular shunt including a housing, a deployment mechanism at least partially disposed within the housing, and a hollow shaft coupled inside the housing to the deployment mechanism, wherein the shaft is configured to hold an intraocular shunt, in which the device includes an insertion configuration and a deployment configuration and the deployment configuration includes a proximal portion of the shaft being at least partially retracted to within the housing. In certain embodiments, the insertion configuration includes a distal portion of the shaft being disposed within the housing and a proximal portion of the shaft extending beyond the housing. 
     In certain embodiments, the shaft is configured to at least partially retract to within the housing. However, it will be appreciated that the shaft may fully retract to within the housing. In certain embodiments, the device further includes the intraocular shunt. The shunt may be completely disposed within the hollow shaft of the device. Alternatively, the shunt is partially disposed within the hollow shaft of the device. 
     The deployment mechanism may include a two stage system. In such embodiments, the first stage is a pusher component and the second stage is a retraction component. In this embodiment, rotation of the deployment mechanism sequentially engages the pusher component and then the retraction component. The pusher component pushes the shunt to partially deploy the shunt from within the shaft, and the retraction component retracts the shaft from around the shunt, thereby deploying the shunt. In certain embodiments, the deployment mechanism may additionally include at least one member that limits axial movement of the shaft. 
     The hollow shaft of the deployment device may include a beveled distal end. An exemplary hollow shaft is a needle. Devices of the invention may be completely automated, partially automated, or completely manual. Devices of the invention may be connected to larger robotic systems or may be used as stand-alone handheld deployment devices. In particular embodiments, the device is a handheld device. 
     Devices of the invention may include an indicator that provides feedback to an operator as to the state of the deployment mechanism. The indicator may be any type of indicator known in the art, for example a visual indicator, an audio indicator, or a tactile indicator. In certain embodiments, the indicator is a visual indicator. 
     Aspects of the invention also include methods for deploying an intraocular shunt within an eye. These methods involve using devices described herein to deploy an intraocular shunt from the device within the eye. Generally, deploying the shunt results in a flow path from an anterior chamber of the eye to an area of lower pressure. Exemplary areas of lower pressure include intra-Tenon&#39;s space, the subconjunctival space, the episcleral vein, the suprachoroidal space, and Schlemm&#39;s canal. In certain embodiments, the area of lower pressure is the subarachnoid space. 
     Any of a variety of methods known in the art may be used to insert devices of the invention into an eye. In certain embodiments, devices of the invention may be inserted into the eye using an ab externo approach (entering through the conjunctiva) or an ab interno approach (entering through the cornea). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic showing an embodiment of a shunt deployment device according to the invention. 
         FIG. 2  shows an exploded view of the device shown in  FIG. 1 . 
         FIGS. 3A-3D  are schematics showing different enlarged views of the deployment mechanism of the deployment device. 
         FIGS. 4A-4C  are schematics showing interaction of the deployment mechanism with a portion of the housing of the deployment device. 
         FIG. 5  shows a cross sectional view of the deployment mechanism of the deployment device. 
         FIGS. 6A-6B  show schematics of the deployment mechanism in a pre-deployment configuration. 
         FIG. 6C  shows an enlarged view of the distal portion of the deployment device of  FIG. 6A . This figure shows an intraocular shunt loaded within a hollow shaft of the deployment device. 
         FIGS. 7A-7B  show schematics of the deployment mechanism at the end of the first stage of deployment of the shunt from the deployment device. 
         FIG. 7C  shows an enlarged view of the distal portion of the deployment device of  FIG. 7A . This figure shows an intraocular shunt partially deployed from within a hollow shaft of the deployment device. 
         FIG. 8A  shows a schematic of the deployment device after deployment of the shunt from the device. 
         FIG. 8B  show a schematic of the deployment mechanism at the end of the second stage of deployment of the shunt from the deployment device. 
         FIG. 8C  shows an enlarged view of the distal portion of the deployment device after retraction of the shaft with the pusher abutting the shunt. 
         FIG. 8D  shows an enlarged view of the distal portion of the deployment device after deployment of the shunt. 
         FIGS. 9A-9B  show an intraocular shunt deployed within the eye. A proximal portion of the shunt resides in the anterior chamber and a distal portion of the shunt resides within the intra-Tenon&#39;s space. A middle portion of the shunt resides in the sclera. 
         FIG. 10  depicts a schematic of an exemplary intraocular shunt. 
     
    
    
     DETAILED DESCRIPTION 
     Reference is now made to  FIG. 1 , which shows an embodiment of a shunt deployment device  100  according to the invention. While  FIG. 1  shows a handheld manually operated shunt deployment device, it will be appreciated that devices of the invention may be coupled with robotic systems and may be completely or partially automated. As shown in  FIG. 1 , deployment device  100  includes a generally cylindrical body or housing  101 ; however, the body shape of housing  101  could be other than cylindrical. Housing  101  may have an ergonomical shape, allowing for comfortable grasping by an operator. Housing  101  is shown with optional grooves  102  to allow for easier gripping by a surgeon. 
     Housing  101  is shown having a larger proximal portion that tapers to a distal portion. The distal portion includes a hollow sleeve  105 . The hollow sleeve  105  is configured for insertion into an eye and to extend into an anterior chamber of an eye. The hollow sleeve is visible within an anterior chamber of an eye. The sleeve  105  provides a visual preview for an operator as to placement of the proximal portion of the shunt within the anterior chamber of an eye. Additionally, the sleeve  105  provides a visual reference point that may be used by an operator to hold device  100  steady during the shunt deployment process, thereby assuring optimal longitudinal placement of the shunt within the eye. 
     The sleeve  105  may include an edge  131  at a distal end that provides resistance feedback to an operator upon insertion of the deployment device  100  within an eye of a person. Upon advancement of the device  100  across an anterior chamber of the eye, the hollow sleeve  105  will eventually contact the sclera  134 , providing resistance feedback to an operator that no further advancement of the device  100  is necessary. The edge  131  of the sleeve  105  prevents the shaft  104  from accidentally being pushed too far through the sclera. A temporary guard  108  is configured to fit around sleeve  105  and extend beyond an end of sleeve  105 . The guard is used during shipping of the device and protects an operator from a distal end of a hollow shaft  104  that extends beyond the end of the sleeve  105 . The guard is removed prior to use of the device. 
     Housing  101  is open at its proximal end, such that a portion of a deployment mechanism  103  may extend from the proximal end of the housing  101 . A distal end of housing  101  is also open such that at least a portion of a hollow shaft  104  may extend through and beyond the distal end of the housing  101 . Housing  101  further includes a slot  106  through which an operator, such as a surgeon, using the device  100  may view an indicator  107  on the deployment mechanism  103 . 
     Housing  101  may be made of any material that is suitable for use in medical devices. For example, housing  101  may be made of a lightweight aluminum or a biocompatible plastic material. Examples of such suitable plastic materials include polycarbonate and other polymeric resins such as DELRIN and ULTEM. In certain embodiments, housing  101  is made of a material that may be autoclaved, and thus allow for housing  101  to be re-usable. Alternatively, device  100  may be sold as a one-time-use device, and thus the material of the housing does not need to be a material that is autoclavable. 
     Housing  101  may be made of multiple components that connect together to form the housing.  FIG. 2  shows an exploded view of deployment device  100 . In this figure, housing  101 , is shown having three components  101   a ,  101   b , and  101   c . The components are designed to screw together to form housing  101 .  FIG. 2  also shows deployment mechanism  103 . The housing  101  is designed such that deployment mechanism  103  fits within assembled housing  101 . Housing  101  is designed such that components of deployment mechanism  103  are movable within housing  101 . 
       FIGS. 3A-3D  show different enlarged views of the deployment mechanism  103 . Deployment mechanism  103  may be made of any material that is suitable for use in medical devices. For example, deployment mechanism  103  may be made of a lightweight aluminum or or a biocompatible plastic material. Examples of such suitable plastic materials include polycarbonate and other polymeric resins such as DELRIN and ULTEM. In certain embodiments, deployment mechanism  103  is made of a material that may be autoclaved, and thus allow for deployment mechanism  103  to be re-usable. Alternatively, device  100  may be sold as a one-time-use device, and thus the material of the deployment mechanism does not need to be a material that is autoclavable. 
     Deployment mechanism  103  includes a distal portion  109  and a proximal portion  110 . The deployment mechanism  103  is configured such that distal portion  109  is movable within proximal portion  110 . More particularly, distal portion  109  is capable of partially retracting to within proximal portion  110 . 
     In this embodiment, the distal portion  109  is shown to taper to a connection with a hollow shaft  104 . This embodiment is illustrated such that the connection between the hollow shaft  104  and the distal portion  109  of the deployment mechanism  103  occurs inside the housing  101 . In other embodiments, the connection between hollow shaft  104  and the proximal portion  109  of the deployment mechanism  103  may occur outside of the housing  101 . Hollow shaft  104  may be removable from the distal portion  109  of the deployment mechanism  103 . Alternatively, the hollow shaft  104  may be permanently coupled to the distal portion  109  of the deployment mechanism  103 . 
     Generally, hollow shaft  104  is configured to hold an intraocular shunt  115 . An exemplary intraocular shunt  115  is shown in  FIG. 11 . Other exemplary intraocular shunts are shown in Yu et al. (U.S. Patent Application No. 2008/0108933). Generally, in one embodiment, intraocular shunts are of a cylindrical shape and have an outside cylindrical wall and a hollow interior. The shunt may have an inner diameter of approximately 50 μm to approximately 250 μm, an outside diameter of approximately 190 μm to approximately 300 μm, and a length of approximately 0.5 mm to about 20 mm. Thus, hollow shaft  104  is configured to at least hold a shunt of such shape and such dimensions. However, hollow shaft  104  may be configured to hold shunts of different shapes and different dimensions than those described above, and the invention encompasses a shaft  104  that may be configured to hold any shaped or dimensioned intraocular shunt. In particular embodiments, the shaft has an inner diameter of approximately 200 μm to approximately 400 μm. 
     The shaft  104  may be any length. A usable length of the shaft may be anywhere from about 5 mm to about 40 mm, and is 15 mm in certain embodiments. In certain embodiments, the shaft is straight. In other embodiments, shaft is of a shape other than straight, for example a shaft having a bend along its length or a shaft having an arcuate portion. Exemplary shaped shafts are shown for example in Yu et al. (U.S. Patent Application No. 2008/0108933). 
     In particular embodiments, the shaft includes a bend at a distal portion of the shaft. In other embodiments, a distal end of the shaft  104  is beveled or is sharpened to a point to assist in piercing the sclera and advancing the distal end of the shaft  104  through the sclera. In particular embodiments, the distal end of the shaft  104  has a double bevel. The double bevel provides an angle at the distal end of the shaft  104  such that upon entry of the shaft into intra-Tenon&#39;s space, the distal end of shaft  104  will by parallel with Tenon&#39;s capsule and will thus not pierce Tenon&#39;s capsule and enter the subconjunctival space. This ensures proper deployment of the shunt such that a distal end of the shunt  115  is deployed within the intra-Tenon&#39;s space, rather than deployment of the distal end of the shunt  115  within the subconjunctival space. Changing the angle of the bevel allows for placement of shunt  115  within other areas of lower pressure than the anterior chamber, such as the subconjunctival space. It will be understood that implanting into intra-Tenon&#39;s space merely one embodiment of where shunt  115  may be placed within the eye, and that devices of the invention are not limited to placing shunts within intra-Tenon&#39;s space and may be used to place shunts into many other areas of the eye, such as Schlemm&#39;s canal, the subconjunctival space, the episcleral vein, or the suprachoroidal space. 
     The shaft  104  may hold the shunt at least partially within the hollow interior of the shaft  104 . In other embodiments, the shunt is held completely within the hollow interior of the shaft  104 . Alternatively, the hollow shaft may hold the shunt on an outer surface of the shaft  104 . In particular embodiments, the shunt is held within the hollow interior of the shaft  104 . In certain embodiments, the hollow shaft is a needle having a hollow interior. Needles that are configured to hold an intraocular shunt are commercially available from Terumo Medical Corp. (Elkington, Md.). 
     A proximal portion of the deployment mechanism includes optional grooves  116  to allow for easier gripping by an operator for easier rotation of the deployment mechanism, which will be discussed in more detail below. The proximal portion  110  of the deployment mechanism also includes at least one indicator that provides feedback to an operator as to the state of the deployment mechanism. The indicator may be any type of indicator known in the art, for example, a visual indicator, an audio indicator, or a tactile indicator.  FIG. 3A  shows a deployment mechanism having two indicators, a ready indicator  111  and a deployed indicator  119 . Ready indicator  111  provides feedback to an operator that the deployment mechanism is in a configuration for deployment of an intraocular shunt from the deployment device  100 . The indicator  111  is shown in this embodiment as a green oval having a triangle within the oval. Deployed indicator  119  provides feedback to the operator that the deployment mechanism has been fully engaged and has deployed the shunt from the deployment device  100 . The deployed indicator  119  is shown in this embodiment as a yellow oval having a black square within the oval. The indicators are located on the deployment mechanism such that when assembled, the indicators  111  and  119  may be seen through slot  106  in housing  101 . 
     The proximal portion  110  includes a stationary portion  110   b  and a rotating portion  110   a . The proximal portion  110  includes a channel  112  that runs part of the length of stationary portion  110   b  and the entire length of rotating portion  110   a . The channel  112  is configured to interact with a protrusion  117  on an interior portion of housing component  101   a  ( FIGS. 4A and 4B ). During assembly, the protrusion  117  on housing component  101   a  is aligned with channel  112  on the stationary portion  110   b  and rotating portion  110   a  of the deployment mechanism  103 . The proximal portion  110  of deployment mechanism  103  is slid within housing component  101   a  until the protrusion  117  sits within stationary portion  110   b  ( FIG. 4C ). Assembled, the protrusion  117  interacts with the stationary portion  110   b  of the deployment mechanism  103  and prevents rotation of stationary portion  110   b . In this configuration, rotating portion  110   a  is free to rotate within housing component  101   a.    
     Referring back to  FIGS. 3A-3D , the rotating portion  110   a  of proximal portion  110  of deployment mechanism  103  also includes channels  113   a ,  113   b , and  113   c . Channel  113   a  includes a first portion  113   a   1  that is straight and runs perpendicular to the length of the rotating portion  110   a , and a second portion  113   a   2  that runs diagonally along the length of rotating portion  110   a , downwardly toward a proximal end of the deployment mechanism  103 . Channel  113   b  includes a first portion  113   b   1  that runs diagonally along the length of the rotating portion  110   a , downwardly toward a distal end of the deployment mechanism  103 , and a second portion that is straight and runs perpendicular to the length of the rotating portion  110   a . The point at which first portion  113   a   1  transitions to second portion  113   a   2  along channel  113   a , is the same as the point at which first portion  113   b   1  transitions to second portion  113   b   2  along channel  113   b.  Channel  113   c  is straight and runs perpendicular to the length of the rotating portion  110   a . Within each of channels  113   a ,  113   b , and  113   c , sit members  114   a ,  114   b , and  114   c  respectively. Members  114   a ,  114   b , and  114   c  are movable within channels  113   a ,  113   b , and  113   c . Members  114   a ,  114   b , and  114   c  also act as stoppers that limit movement of rotating portion  110   a , which thereby limits axial movement of the shaft  104 . 
       FIG. 5  shows a cross-sectional view of deployment mechanism  103 . Member  114   a  is connected to the distal portion  109  of the deployment mechanism  103 . Movement of member  114   a  results in retraction of the distal portion  109  of the deployment mechanism  103  to within the proximal portion  110  of the deployment mechanism  103 . Member  114   b  is connected to a pusher component  118 . The pusher component  118  extends through the distal portion  109  of the deployment mechanism  103  and extends into a portion of hollow shaft  104 . The pusher component is involved in deployment of a shunt from the hollow shaft  104 . An exemplary pusher component is a plunger. Movement of member  114   b  engages pusher  118  and results in pusher  118  advancing within hollow shaft  104 . 
     Reference is now made to  FIGS. 6A-8D , which accompany the following discussion regarding deployment of a shunt  115  from deployment device  100 .  FIG. 6A  shows deployment device  100  is a pre-deployment configuration. In this configuration, shunt  115  is loaded within hollow shaft  104  ( FIG. 6C ). As shown in  FIG. 6C , shunt  115  is only partially within shaft  104 , such that a portion of the shunt is exposed. However, the shunt  115  does not extend beyond the end of the shaft  104 . In other embodiments, the shunt  115  is completely disposed within hollow shaft  104 . The shunt  115  is loaded into hollow shaft  104  such that the shunt abuts pusher component  118  within hollow shaft  104 . A distal end of shaft  104  is beveled to assist in piercing tissue of the eye. 
     Additionally, in the pre-deployment configuration, a portion of the shaft  104  extends beyond the sleeve  105  ( FIG. 6C ). The deployment mechanism is configured such that member  114   a  abuts a distal end of the first portion  113   a   1  of channel  113   a , and member  114   b  abut a proximal end of the first portion  113   b   1  of channel  113   b  ( FIG. 6B ). In this configuration, the ready indicator  111  is visible through slot  106  of the housing  101 , providing feedback to an operator that the deployment mechanism is in a configuration for deployment of an intraocular shunt from the deployment device  100  ( FIG. 6A ). In this configuration, the device  100  is ready for insertion into an eye (insertion configuration or pre-deployment configuration). Methods for inserting and implanting shunts are discussed in further detail below. 
     Once the device has been inserted into the eye and advanced to a location to where the shunt will be deployed, the shunt  115  may be deployed from the device  100 . The deployment mechanism  103  is a two-stage system. The first stage is engagement of the pusher component  118  and the second stage is retraction of the distal portion  109  to within the proximal portion  110  of the deployment mechanism  103 . Rotation of the rotating portion  110   a  of the proximal portion  110  of the deployment mechanism  103  sequentially engages the pusher component and then the retraction component. 
     In the first stage of shunt deployment, the pusher component is engaged and the pusher partially deploys the shunt from the deployment device. During the first stage, rotating portion  110   a  of the proximal portion  110  of the deployment mechanism  103  is rotated, resulting in movement of members  114   a  and  114   b  along first portions  113   a   1  and  113   b   1  in channels  113   a  and  113   b . Since the first portion  113   a   1  of channel  113   a  is straight and runs perpendicular to the length of the rotating portion  110   a , rotation of rotating portion  110   a  does not cause axial movement of member  114   a . Without axial movement of member  114   a , there is no retraction of the distal portion  109  to within the proximal portion  110  of the deployment mechanism  103 . Since the first portion  113   b   1  of channel  113   b  runs diagonally along the length of the rotating portion  110   a , upwardly toward a distal end of the deployment mechanism  103 , rotation of rotating portion  110   a  causes axial movement of member  114   b  toward a distal end of the device. Axial movement of member  114   b  toward a distal end of the device results in forward advancement of the pusher component  118  within the hollow shaft  104 . Such movement of pusher component  118  results in partially deployment of the shunt  115  from the shaft  104 . 
       FIGS. 7A-7C  show schematics of the deployment mechanism at the end of the first stage of deployment of the shunt from the deployment device. As is shown  FIG. 7A , members  114   a  and  114   b  have finished traversing along first portions  113   a   1  and  113   b   1  of channels  113   a  and  113   b . Additionally, pusher component  118  has advanced within hollow shaft  104  ( FIG. 7B ), and shunt  115  has been partially deployed from the hollow shaft  104  ( FIG. 7C ). As is shown in these figures, a portion of the shunt  115  extends beyond an end of the shaft  104 . 
     In the second stage of shunt deployment, the retraction component is engaged and the distal portion of the deployment mechanism is retracted to within the proximal portion of the deployment mechanism, thereby completing deployment of the shunt from the deployment device. During the second stage, rotating portion  110   a  of the proximal portion  110  of the deployment mechanism  103  is further rotated, resulting in movement of members  114   a  and  114   b  along second portions  113   a   2  and  113   b   2  in channels  113   a  and  113   b . Since the second portion  113   b   2  of channel  113   b  is straight and runs perpendicular to the length of the rotating portion  110   a , rotation of rotating portion  110   a  does not cause axial movement of member  114   b . Without axial movement of member  114   b , there is no further advancement of pusher  118 . Since the second portion  113   a   2  of channel  113   a  runs diagonally along the length of the rotating portion  110   a , downwardly toward a proximal end of the deployment mechanism  103 , rotation of rotating portion  110   a  causes axial movement of member  114   a  toward a proximal end of the device. Axial movement of member  114   a  toward a proximal end of the device results in retraction of the distal portion  109  to within the proximal portion  110  of the deployment mechanism  103 . Retraction of the distal portion  109 , results in retraction of the hollow shaft  104 . Since the shunt  115  abuts the pusher component  118 , the shunt remains stationary as the hollow shaft  104  retracts from around the shunt  115  ( FIG. 8C ). The shaft  104  retracts almost completely to within the sleeve  105 . During both stages of the deployment process, the sleeve  105  remains stationary and in a fixed position. 
       FIG. 8A  shows a schematic of the device  100  after deployment of the shunt  115  from the device  100 .  FIG. 8B  shows a schematic of the deployment mechanism at the end of the second stage of deployment of the shunt from the deployment device. As is shown in  FIG. 8B , members  114   a  and  114   b  have finished traversing along second portions  113   a   2  and  113   b   2  of channels  113   a  and  113   b . Additionally, distal portion  109  has retracted to within proximal portion  110 , thus resulting in retraction of the hollow shaft  104  to within the sleeve  105 .  FIG. 8D  shows an enlarged view of the distal portion of the deployment device after deployment of the shunt. This figure shows that the hollow shaft  104  is not fully retracted to within the sleeve  105  of the deployment device  100 . However, in certain embodiments, the shaft  104  may completely retract to within the sleeve  105 . 
     Referring to  FIG. 8A , in the post-deployment configuration, the deployed indicator  119  is visible through slot  106  of the housing  101 , providing feedback to the operator that the deployment mechanism has been fully engaged and that the shunt  115  has been deployed from the deployment device  100 . 
     Any of a variety of methods known in the art may be used to insert devices of the invention into an eye. In certain embodiments, devices of the invention may be inserted into the eye using an ab externo approach (entering through the conjunctiva) or an ab interno approach (entering through the cornea). 
     In certain embodiments, devices of the invention are inserted into the eye using an ab interno approach. Ab interno approaches for implanting an intraocular shunt are shown for example in Yu et al. (U.S. Pat. No. 6,544,249 and U.S. Patent Application No. 2008/0108933) and Prywes (U.S. Pat. No. 6,007,511), the content of each of which is incorporated by reference herein in its entirety. 
     Devices of the invention may be inserted into the eye to deploy shunts that create fluid drainage passageways from the anterior chamber of the eye to various drainage structures of the eye. Exemplary drainage structures include Schlemm&#39;s canal, the subconjunctival space, the episcleral vein, the suprachoroidal space, or the intra-Tenon&#39;s space. In certain embodiments, fluid is drained to the subarachnoid space. 
     In particular embodiments, devices of the invention are inserted into the eye to deploy shunts that create fluid drainage passageways from the anterior chamber to the intra-Tenon&#39;s space. Within an eye, there is a membrane known as the conjunctiva, and the region below the conjunctiva is known as the subconjunctival space. Within the subconjunctival space is a membrane known as Tenon&#39;s capsule. Below Tenon&#39;s capsule there are Tenon&#39;s adhesions that connect the Tenon&#39;s capsule to the sclera. The space between Tenon&#39;s capsule and the sclera where the Tenon&#39;s adhesions connect the Tenon&#39;s capsule to the sclera is known as the intra-Tenon&#39;s space. 
       FIGS. 9A-9B  show an intraocular shunt placed into the eye using devices of the invention such that the shunt forms a passage for fluid drainage from the anterior chamber to the intra-Tenon&#39;s space. To place the shunt within the eye, a surgical intervention to implant the shunt is performed that involves inserting into the eye  202  a deployment device  200  that holds an intraocular shunt  201 , and deploying at least a portion of the shunt  201  within intra-Tenon&#39;s space  208 , within the subconjunctival space  209  and below the conjunctiva  210 . In certain embodiments, a hollow shaft  206  of a deployment device  200  holding the shunt  201  enters the eye  202  through the cornea  203  (ab interno approach). The shaft  206  is advanced across the anterior chamber  204  (as depicted by the broken line) in what is referred to as a transpupil implant insertion. The shaft  206  is advanced through the sclera  205  until a distal portion of the shaft  206  is in proximity to Tenon&#39;s capsule  207 . 
     Once a distal portion of the hollow shaft  206  is within the intra-Tenon&#39;s space  208 , the shunt  201  is then deployed from the shaft  206  of the deployment device  200 , producing a conduit between the anterior chamber  204  and the intra-Tenon&#39;s space  208  to allow aqueous humor to drain from the anterior chamber  204  (see  FIGS. 9A and 9B ). 
     COMBINATIONS OF EMBODIMENTS 
     As will be appreciated by one skilled in the art, individual features of the invention may be used separately or in any combination. Particularly, it is contemplated that one or more features of the individually described above embodiments may be combined into a single shunt. 
     INCORPORATION BY REFERENCE 
     References and citations to other documents, such as patents, patent applications, patent publications, journals, books, papers, web contents, have been made throughout this disclosure. All such documents are hereby incorporated herein by reference in their entirety for all purposes. 
     EQUIVALENTS 
     The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting on the invention described herein.