Ophthalmic treatment cannula

Abstract

Certain aspects of the present disclosure relate generally to ophthalmic surgery, and more specifically to methods and devices for controlling intraocular pressure (IOP) and administering ophthalmic tamponade during or after ophthalmic surgery. An exemplary device generally includes a proximal segment having a first inner diameter (ID), a first proximal end, and a first distal end. The device further includes a distal segment having a second ID smaller than the first ID, a second proximal end, and a second distal end configured to be disposed within a hub or cannula transition of a valved cannula including a hub, a shaft, and a cannula transition between the hub and shaft.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 223,645, entitled "CANNULAS FOR OPHTHALMIC PROCEDURES," filed on July 20, 2021, by inventors Ashish Sinha and Robert Jeffrey Heng, which is incorporated by reference in its entirety as if fully and completely set forth herein.

[0002] The present disclosure relates generally to devices, systems, and methods for controlling intraocular pressure (IOP) and / or administering ophthalmic tamponade during or after ophthalmic surgery, etc. More specifically, the present disclosure relates to ophthalmic cannulas, such as infusion and injection cannulas, and methods of their use. [Background technology]

[0003] Posterior segment surgical procedures are performed to treat conditions at the back of the eye, such as age-related macular degeneration (AMD), diabetic retinopathy and diabetic vitreous hemorrhage, macular holes, retinal detachment, epiretinal membrane, and cytomegalovirus (CMV) retinitis.

[0004] Certain problems affecting the back of the eye may require vitrectomy, i.e., surgical removal of the vitreous, which is a typically clear, gel-like substance that fills the center of the eye and helps give it its form and shape. For example, vitrectomy may be performed to clear blood and debris from the eye, remove scar tissue, and relieve traction on the retina. During this procedure, three separate incisions are made in the pars plana of the eye, just behind the iris but in front of the retina. The incisions are used to pass instruments, such as light pipes, injection ports, and / or vitreous surgery cutting devices, into the eye. A valved cannula is placed within each incision to allow instrument access into the eye via the cannula while providing a self-sealing valve that passively controls fluid and pressure communication between the interior and exterior of the eye via the cannula.

[0005] When vitreous humor is aspirated during posterior segment surgery, the intraocular pressure (IOP) decreases and the patient's eye tends to soften. An infusion cannula may be coupled to the valved cannula to infuse fluids, such as liquids or gases (e.g., balanced saline solution (BSS)), into the eye to maintain the IOP and avoid deformation or collapse of the eye. In addition, maintaining the IOP can maintain the rigidity of the sclera and facilitate eye movement and instrument exchange during the procedure. However, the IOP must be carefully regulated, as prolonged high IOP can damage the eye's structures. If the IOP becomes too high, another infusion cannula can be used to drain fluid from the eye to relieve the pressure.

[0006] In another embodiment, an injection cannula can be coupled to a valved cannula and used to inject a viscous fluid, such as an ophthalmic tamponade, into the ocular space to prevent fluid flow through retinal breaks. The tamponade replaces the vitreous body removed during vitreous surgery and can be a gas or a solution (e.g., silicone oil). After the procedure, the tamponade may be left in the patient's eye for a period of time and then extracted.

[0007] Conventional fluid cannulas (e.g., infusion cannulas, injection cannulas, etc.) have various drawbacks. For example, conventional fluid cannulas are typically size-specific, with each fluid cannula having dimensions for the particular gauge of valved cannula to which it is to be mated. Valved cannulas are available in several different gauges (e.g., 23 gauge, 25 gauge, and 27 gauge), and thus, a user (e.g., an ophthalmic surgeon) must have available a fluid cannula that is specifically sized for the gauge of the valved cannula desired for a surgical procedure. Using valved cannulas of different sizes adds inconvenience to the procedure. Additionally, conventional fluid cannula designs create relatively high fluid friction for the fluid passing therethrough. High fluid friction restricts the overall fluid flow and requires high pressure to maintain a given fluid flow rate. Operating at higher pressures may require larger pumps, which can cause additional wear and damage to the equipment. In certain instances, the limitations of conventional tubing sets and viscous fluid delivery systems at high pressures can result in burst failure and disconnection. Additionally, operating at lower pressures can minimize the risk of harm to eye tissue.

[0008] Thus, there is a need for improved devices, systems, and methods for controlling IOP and administering fluids, and in particular an improved fluid cannula that addresses at least some of the above-mentioned shortcomings. Summary of the Invention [Means for solving the problem]

[0009] The present disclosure relates generally to devices, systems, and methods for controlling intraocular pressure during ophthalmic surgery, such as posterior segment surgical procedures, including vitreous surgery. More specifically, certain aspects of the disclosure relate to injection cannulas and methods of use thereof that are useful for injecting / withdrawing fluids from the eye. Further aspects of the disclosure relate to injection cannulas and methods of use thereof that are useful for injecting / withdrawing fluids from the eye.

[0010] Certain aspects provide a cannula apparatus for a surgical procedure having a proximal segment including a first inner diameter (ID), a first proximal end, and a first distal end, and a distal segment including a second ID smaller than the first ID, a second proximal end, and a second distal end configured to be positioned within a hub or cannula transition of a valved cannula including a hub, a shaft, and a cannula transition between the hub and shaft.

[0011] Certain aspects provide a cannula device for a surgical procedure having a proximal segment including a first inner diameter (ID), a first proximal end, and a first distal end; a middle segment including a second ID smaller than the first ID, a second proximal end, and a second distal end; a first transition portion connecting the proximal segment and the middle segment via the first distal end and the second proximal end, the first transition portion including a first fillet and a second fillet; a distal segment including a third ID smaller than the second ID, a third proximal end, and a third distal end; and a second transition portion connecting the middle segment and the distal segment via the second distal end and the third proximal end, the second transition portion including a third fillet and a fourth fillet.

[0012] The following description and the related drawings set forth in detail certain illustrative features of the one or more embodiments.

[0013] The accompanying drawings depict certain aspects of one or more embodiments and therefore should not be considered as limiting the scope of the present disclosure. The figures disclosed herein may not be to scale. [Brief description of the drawings]

[0014] [Figure 1A-1B] 1A-1D are isometric and cross-sectional side views of an exemplary injection cannula assembly including a viscous fluid control (VFC) cannula, in accordance with certain embodiments of the present disclosure. [Figure 2A-2B]1C are isometric and cross-sectional side views of the VFC cannula of FIGS. 1A and 1B coupled to a valved cannula in accordance with a specific embodiment of the present disclosure. [Fig. 2C-2D] 1C are isometric and cross-sectional side views of the VFC cannula of FIGS. 1A and 1B in accordance with a specific embodiment of the present disclosure. [Fig. 2E-2F] 1C are isometric and cross-sectional side views of an alternative VFC cannula of FIGS. 1A and 1B in accordance with certain embodiments of the present disclosure. [Figure 3A-3B] 1A-1D are isometric and cross-sectional side views of an alternative VFC cannula coupled to a valved cannula in accordance with certain embodiments of the present disclosure. [Figure 3C-3D] 3B is an isometric view and a cross-sectional side view of an alternative VFC cannula of FIG. 3A in accordance with a specific embodiment of the present disclosure. [Figure 4A-4B] 1A-1D are isometric and cross-sectional side views of an exemplary infusion cannula coupled to a valved cannula, in accordance with certain embodiments of the present disclosure. [Fig. 4C-4D] 4B is an isometric view and a cross-sectional side view of the exemplary infusion cannula of FIG. 4A in accordance with certain embodiments of the present disclosure.

[0015] For ease of understanding, the same reference numbers have been used wherever possible to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further description. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] In the following description, details are described by way of example to facilitate understanding of the disclosed subject matter. However, it should be clear to those skilled in the art that the disclosed implementations are illustrative and do not cover all possible implementations. Therefore, it should be understood that reference to the described examples is not intended to limit the scope of the present disclosure. Any changes and further modifications to the described devices, apparatuses, methods, and any further applications of the principles of the present disclosure are fully anticipated as would normally occur to a person skilled in the art to which the present disclosure pertains. In particular, it is fully anticipated that features, components, and / or steps described with respect to one implementation can be combined with features, components, and / or steps described with respect to other implementations of the present disclosure.

[0017] It should be noted that, as described herein, a distal end, segment, or portion of a component refers to the end, segment, or portion that is closer to the patient's body during its use, whereas a proximal end, segment, or portion of a component refers to the end, segment, or portion that is located further away from the patient's body, and an intermediate segment or portion of a component refers to the segment or portion that is located between the distal segment or portion and the proximal end or portion.

[0018] As used herein, the term "about" can refer to a + / - 10% variation from the nominal value. It is to be understood that such a variation may be included in any value provided herein.

[0019] The embodiments of the present disclosure provide devices, systems, and methods for controlling intraocular pressure (IOP) and / or administering fluids, such as ocular tamponade, to the ocular space. More specifically, the embodiments described herein disclose injection cannulas and methods of use thereof that are useful for injecting and / or extracting fluids from the eye, as described in further detail below. Further aspects of the present disclosure relate to injection cannulas and methods of use thereof that are useful for injecting and / or draining fluids from the eye, as described in further detail below. Furthermore, the techniques and designs described herein may be applicable to other types of fluid cannulas as well. As described herein, the fluid cannulas are coupled to valved cannulas, but it should be noted that in certain aspects, non-valved cannulas may be used in place of the valved cannulas. Also, while described with reference to vitreoretinal procedures, it should be noted that the devices, systems, and methods described herein are also applicable to other types of cannulas or uses and are not limited to only ophthalmic procedures.

[0020] Conventional fluid cannulas include an internal diameter (ID) that may restrict fluid flow to a level lower than what the valved cannula can actually support. For example, the minimum ID of a conventional fluid cannula is smaller than the corresponding minimum ID of a valved cannula through which the fluid can flow. The minimum ID of a fluid cannula restricts fluid flow because the resistance to fluid flow (R) is directly proportional to the viscosity of the fluid (η) and the length of the passageway through which the fluid flows (L), where the fluid passageway is a portion of the fluid cannula with a constant ID. Furthermore, the resistance to fluid flow is proportional to the fourth power of the radius of the fluid passageway (r 4 ), where the radius is one-half the ID of the fluid passage. Therefore, the resistance to fluid flow is also inversely proportional to the ID of the fluid passage, as follows:

number

[0021] Thus, because conventional fluid cannulas include segments having IDs smaller than the minimum ID of the corresponding valved cannula, these segments of the conventional fluid cannula restrict fluid flow to a level less than the level that the valved cannula can actually support.

[0022] Certain embodiments described herein provide fluid cannulas that may have one or more of the following features, each of which provides advantages: The fluid cannula may have a distal segment with an ID greater than the smallest ID of a compatible valved cannula. A larger ID reduces resistance to fluid flow because resistance is inversely proportional to the ID of the fluid passage. The fluid cannula may have a distal segment with a shorter length than a conventional fluid cannula. A shorter length of the segment reduces resistance to fluid flow because resistance is proportional to the length of the fluid passage. The fluid cannula may have an intermediate segment that transitions between the proximal and distal segments. The intermediate segment provides a larger diameter for a portion of the length inside the compatible valved cannula, thus reducing resistance to fluid flow. The fluid cannula may have a transition between segments with at least two fillets (e.g., round, curve, cutout, radiating, spline, or similar curvature) and / or chamfers (e.g., beveled). The transition provides a smooth transition between the segments. In this manner, the features described above are configured to reduce the overall flow resistance and pressure drop through the fluid cannula, thereby reducing the pressure required to maintain a given fluid flow rate, or, alternatively, increasing the flow rate at a given source pressure, as described in further detail below.

[0023] FIG. 1A illustrates an isometric view of an exemplary injection cannula assembly 100, according to certain embodiments. The injection cannula assembly 100 generally includes a viscous fluid control (VFC) cannula 102 and an adapter 104. The VFC cannula 102 is configured to be inserted, for example, into a valved cannula (shown in FIGS. 2C-2D) and may be used to inject / extract fluids from the ocular space of a patient's eye through the valved cannula. The adapter 104 connects or fits the VFC cannula 102 to a receiving device, such as a syringe, that may contain fluid for injection. A user, such as a surgeon, can inject fluid from the syringe through the cannula assembly 100 and the valved cannula into the patient's eye. The user can also use the syringe to extract fluid from the patient's eye. In certain embodiments, the receiving device may be a tube of a fluid line and may be connected to a surgical console at its proximal end opposite the VFC cannula 102. In such embodiments, the surgical console may be configured to control or drive the injection or extraction of fluid at a set pressure and / or flow rate through the fluid lines and / or VFC cannula 102.

[0024] Figure 1B illustrates a cross-sectional side view of injection cannula assembly 100 having a VFC cannula 102. In particular, Figure 1B illustrates the interior profile and internal features of VFC cannula 102.

[0025] As shown, the VFC cannula 102 is connected to an adapter 104, which may be made of similar or different materials. In certain embodiments, the VFC cannula 102 comprises a metallic material, such as stainless steel or carbon steel. In certain embodiments, the VFC cannula 102 includes a protective coating formed thereon, such as nickel plating, to resist corrosion and / or microbial growth. In certain embodiments, the adapter 104 includes a thermoplastic elastomer or a rigid polymer, such as polycarbonate, polyethylene, polypropylene, etc.

[0026] The VFC cannula 102 and the adapter 104 may be manufactured using similar or different manufacturing processes. In certain embodiments, the VFC cannula 102 may be manufactured using a deep drawing process or a machining process. In certain embodiments, the adapter 104 may be manufactured using an injection molding process. In certain embodiments, the adapter 104 may be manufactured around the VFC cannula 102 via an insert molding process or an injection overmolding process. In certain embodiments, either or both of the VFC cannula 102 and the adapter 104 may be manufactured using three-dimensional (3D) printing. In certain embodiments where the VFC cannula 102 and the adapter 104 are manufactured separately, the VFC cannula 102 and the adapter 104 may be mechanically connected, such as via slots and tabs, or attached using adhesives or thermal bonding.

[0027] 2A and 2B show isometric and cross-sectional side views, respectively, of VFC cannula 102 coupled to valved cannula 220. In particular, Figures 2A and 2B show the exterior profile and exterior features of VFC cannula 102 coupled to valved cannula 220. VFC cannula 102 is configured to be inserted into valved cannula 220 and to infuse, evacuate, or extract fluid from the ocular space of a patient's eye through the valved cannula.

[0028] As shown, the VFC cannula 102 includes a proximal segment 202 and a distal segment 204. The proximal segment 202 includes a first proximal end 203A and a first distal end 203B. The distal segment 204 includes a second proximal end 205A and a second distal end 205B. A first transition section 206 connects the proximal segment 202 and the distal segment 204 via the first distal end 203B and the second proximal end 205A. In certain embodiments, a second transition section 208 connects the proximal segment 202 and the top rim 210 at the first proximal end 203A. The second transition section 208 and / or the top rim 210 may be molded to an adapter (e.g., adapter 104 of FIG. 1B) or bonded to the adapter. In certain embodiments, VFC cannula 102 does not have an apical rim, and proximal segment 202 is at its proximal-most portion.

[0029] Valved cannula 220 generally includes an overcap 222, a hub 226, and a hollow tube or shaft 228. Hub 226 and shaft 228 are connected by a cannula transition 230. The inner diameter (ID) of hub 226 (e.g., ID 227 in FIG. 2B) is larger than the ID of shaft 228 (e.g., ID 229 in FIG. 2B). Valved cannula 220 further includes a recess 232, which may be part of hub 226 and / or cannula transition 230.

[0030] 2B , second distal end 205B of distal segment 204 of VFC cannula 102 is disposed within hub 226 when VFC cannula 102 is coupled to valved cannula 220. In certain embodiments, when VFC cannula 102 is inserted into valved cannula 220 to couple VFC cannula 102 to valved cannula 220, at least a portion of VFC cannula 102 frictionally engages with an internal feature of valved cannula 220. For example, at least a portion of distal segment 204 frictionally engages with an internal feature of valved cannula 220, where the internal feature includes recess 232 and / or an inner wall of valved cannula 220.

[0031] In certain embodiments, the recess 232 is sized to provide sufficient resistance between the VFC cannula 102 and the valved cannula 220 to keep the VFC cannula 102 in place during the procedure. In certain embodiments, the resistance between the recess 232 and the VFC cannula 102 is less than the resistance required to withdraw the valved cannula 220 from the eye when withdrawing the VFC cannula 102 from the valved cannula 220. For example, when withdrawing the VFC cannula 102 from the valved cannula 220 while the valved cannula 220 is within the eye, the valved cannula 220 is not withdrawn from the eye. In certain embodiments, the resistance between the VFC cannula 102 and the valved cannula 220 is such that the VFC cannula 102 cannot be separated from the valved cannula 220 without removing the valved cannula 220 from the eye. In certain embodiments, resistance is created between VFC cannula 102 and other regions or sections of valved cannula 220. For example, in some embodiments, the exterior of distal segment 204 frictionally engages with the interior surfaces of hub 226 and / or cannula transition 230.

[0032] 2B, the hub 226 of the valved cannula 220 radially surrounds and couples to the distal segment 204 of the VFC cannula 102 when the VFC cannula 102 is inserted into the valved cannula 220. In certain embodiments, when inserted into the valved cannula 220, the distal segment 204 is disposed only within (i.e., radially inward of) the hub 226, or only within the hub 226 and the cannula transition 230, and the distal segment 204 does not extend into the shaft 228. Because the distal segment 204 does not extend into the shaft 228, the dimensions of the distal segment 204 are not limited by the dimensions of the shaft 228, and in certain embodiments, the minimum ID of the distal segment 204 (e.g., second ID 242 in FIG. 2D) is greater than the ID 229 of the shaft 228 of the valved cannula 220. As previously mentioned, valved cannula 220 can be a 23 gauge valved cannula, a 25 gauge valved cannula, a 27 gauge valved cannula, etc. The relatively larger ID of the distal segment 204 of VFC cannula 102 (e.g., second ID 242 in FIG. 2D ) compared to the ID 229 of shaft 228 is configured to reduce the overall flow resistance and pressure drop through VFC cannula 102, as valved cannula 220 restricts fluid flow to a level less than what the VFC cannula can actually support.

[0033] The shortened distal segment 204 further allows for universal compatibility of the VFC cannula 102 with valved cannulas of different gauges since the distal segment 204 does not need to be adapted to different IDs (e.g., ID 229) of its shaft (e.g., shaft 228). For example, a VFC cannula can universally couple to a 23 gauge valved cannula, a 25 gauge valved cannula, a 27 gauge valved cannula, etc. Thus, the versatility of the VFC cannula 102 beneficially reduces the number of different parts required for a surgical procedure.

[0034] In certain embodiments, the VFC cannula 102 may also provide pressure relief and / or tactile feedback to the user when injecting fluid into the patient's eye. For example, in certain embodiments, when the VFC cannula 102 is inserted into the valved cannula 220, a gap 224 is formed between the distal segment 204 and the hub 226. In such embodiments, the gap 224 between the distal segment 204 and the valved cannula 220 allows the injected fluid to backflow out of the valved cannula 220 and through the overcap 222 because the VFC cannula 102 does not completely seal against the valved cannula 220. Backflow may occur when pressure within the eye is higher than the pressure exerted by the user, allowing the physician to better feel resistance when injecting fluid into the eye.

[0035] It should be noted that in certain embodiments, the exterior of the distal segment 204 may be connected, coupled, or mated with the interior of the hub 226 and / or the cannula transition portion 230 such that no gaps are formed therebetween.

[0036] In certain embodiments, VFC cannula 102 includes retention features for frictionally engaging with internal features of valved cannula 220. For example, distal segment 204 may have a recess or other feature configured to mate, closely fit, and / or accommodate recess 232.

[0037] Due to the relatively large ID and short length of the distal segment 204, a lower source pressure may be used to maintain a given flow rate with the VFC cannula 102 disclosed herein. In certain embodiments, the source pressure is reduced in proportion to the reduction in flow resistance. In certain embodiments, the flow rate is increased at a given source pressure with the injection cannula embodiments disclosed herein. In certain embodiments, the increase in flow rate is generally about 5-30% or more. In certain embodiments, such as an 80 psi source pressure, the increase in flow rate is about 15-30% or more compared to a conventional 25 gauge injection cannula design. In certain embodiments, such as a 30 psi source pressure, the increase in flow rate is about 5-20% or more compared to a conventional 25 gauge injection cannula design.

[0038] Figures 2C and 2D show isometric and cross-sectional side views, respectively, of VFC cannula 102. In particular, Figures 2C and 2D show the exterior profile and exterior features of VFC cannula 102, and Figure 2D includes several example dimensions, provided in inches unless otherwise noted. Note that the labeled dimensions are merely example, and other dimensions for features may be utilized, including different ratios.

[0039] As shown, proximal segment 202 has a first ID 240 and distal segment 204 has a second ID 242. In certain embodiments, distal segment 204 has an inner dimension, e.g., second ID 242, of about 0.020 inches to about 0.030 inches, e.g., about 0.020 inches to about 0.028 inches, e.g., about 0.023 inches. In certain embodiments, the inner dimension of distal segment 204 is greater than 0.030 inches, such as when the exterior of distal segment 204 fits within the interior of a valved cannula hub (e.g., hub 226 of FIG. 2B) and / or cannula transition (e.g., cannula transition 230 of FIG. 2B) or when distal segment 204 has a recess.

[0040] In certain embodiments, the VFC cannula 102 has an inner shaft length 244 (e.g., including distal segment 204 and fillet 206B) of about 0.050 inches to about 0.120 inches, such as about 0.0507 inches. In certain embodiments, the VFC cannula 102 has an overall length 246 of about 0.150 inches to about 0.250 inches, such as about 0.156 inches to about 0.203 inches, such as about 0.156 inches. Thus, in some embodiments, the ratio of the inner shaft length 244 to the overall length 246 of the VFC cannula can be about 0.2 to about 0.4, such as about (0.0507 inches / 0.156 inches=0.325). In certain embodiments, the VFC cannula 102 has an overall width 247 that can be about 0.110 inches to about 0.140 inches, such as about 0.126 inches in diameter. Generally, segments 202 and 204 and transition portions 206 and 208 share a common central axis 212 disposed through the center of VFC cannula 102. In certain embodiments, proximal segment 202 measures a first length 234 along central axis 212 and distal segment 204 measures a second length 235 along central axis 212. Second length 235 may be greater than, less than, or equal to first length 234. While described with segments 202 and 204 and transition portions 206 and 208, it is noted that VFC cannula 102 may be formed from a single unitary body and segments 202 and 204 and transition portions 206 and 208 may refer to portions of the unitary body. It is noted that while features are described herein with specific dimensions or ranges of dimensions, other dimensions and / or IDs are also contemplated.

[0041] In certain embodiments, first transition portion 206 includes first fillet 206A and second fillet 206B, and second transition portion 208 includes third fillet 208A. In certain embodiments, first fillet 206A is concave and second fillet 206B is convex. In certain embodiments, third fillet 208A is concave, while in further embodiments, third fillet 208A is convex.

[0042] 2D, fillets 206A, 206B, and 208A are formed on the inner walls of transition sections 206 and 208. In certain embodiments, fillets are formed on the inner and / or outer walls of transition sections 206 and 208. In certain embodiments, the inner and / or outer walls of segments 202 and 204 are parallel or tapered relative to central axis 212. In some embodiments, the wall thickness of segments 202 and 204 and first and second transition sections 206 and 208 is constant. In some embodiments, the wall thickness may be variable or may vary by feature (e.g., first transition section 206, distal segment 204).

[0043] In certain embodiments, first transition portion 206 includes a first chamfer or bevel (e.g., similar to first chamfer 406C in FIG. 4D ) rather than a fillet (e.g., fillets 206A and 206B). In certain embodiments, second distal end 205B includes a fourth fillet 238, which may be convex, and / or a second chamfer.

[0044] The fillets described herein, including fillets 206A and 206B, can have one or more position angles (e.g., position angle 253) referenced to the position of the midpoint of the fillet relative to the central axis 212. The position angle can be measured between the central axis 212 and a tangent to the midpoint of the fillet. For example, the position angle 253 can be between 1 and 85 degrees. For example, the position angle 253 can be between 10 and 60 degrees. For example, the position angle 253 can be between 20 and 40 degrees. For example, the position angle 253 can be about 26 degrees. In certain embodiments, the fillet can be on an inner surface of a transition portion (e.g., first transition portion 206). In further embodiments, the fillet can be on an outer surface of the transition portion.

[0045] In certain embodiments, a continuous flow path is formed between first proximal end 203A and second distal end 205B of VFC cannula 102. The curvature of transitions 206 and 208 may therefore allow fluid to flow smoothly through VFC cannula 102 by reducing frictional losses of the fluid, thereby beneficially improving fluid performance. In certain embodiments, the inner walls of segments 202 and 204 and transitions 206 and 208 seamlessly connect to form a smooth inner profile such that there are no signs of unbonded transitions, interruptions, or imbalances between segments 202 and 204 and transitions 206 and 208.

[0046] Figures 2E and 2F show isometric and cross-sectional side views, respectively, of another VFC cannula, designated VFC cannula 200. In particular, Figures 2E and 2F show the exterior profile and exterior features of VFC cannula 200. VFC cannula 200 is substantially similar to VFC cannula 102, and like reference numbers are used where appropriate.

[0047] Unlike VFC cannula 102, however, first transition section 206 of VFC cannula 200 includes a first chamfer or bevel 206C disposed between fillets 206A and 206B. In certain embodiments, transition angle θ (e.g., first transition angle 252 in FIG. 2F ) is measured between first chamfer 206C and an axis of one of segments 202 or 204, which may not be collinear with central axis 212. In certain embodiments, transition angle θ is measured between first chamfer 206C and central axis 212. In certain embodiments, transition angle θ is about 120 degrees, but in further embodiments, transition angle θ may be about 90 degrees, up to and including about 165 degrees. In further embodiments, transition angle θ is greater than 90 degrees.

[0048] The configuration of first transition section 206 can improve fluid flow through VFC cannula 200. As shown, first transition section 206 includes a first chamfer 206C that forms a funnel-shaped feature in VFC cannula 200 with a gradual decrease in ID between proximal segment 202 and distal segment 204. The chamfer facilitates preventing excessive pressure loss compared to conventional VFC cannula transitions by providing a gradual, linearly decreasing reduction in cross section for the fluid.

[0049] 3A and 3B show isometric and cross-sectional side views, respectively, of an alternative VFC cannula 300 coupled to valved cannula 220. In particular, FIGS. 3A-3B show the exterior profiles and exterior features of VFC cannula 300 and valved cannula 120.

[0050] As shown, VFC cannula 300 includes a proximal segment 302, a middle segment 314, and a distal segment 304. Proximal segment 302 includes a first proximal end 303A and a first distal end 303B, middle segment 314 includes a second proximal end 315A and a second distal end 315B, and distal segment 304 includes a third proximal end 305A and a third distal end 305B. A first transition section 306 connects proximal segment 302 and middle segment 314 at first distal end 303B and second proximal end 315A. A second transition section 307 connects middle segment 314 and distal segment 304 at second distal end 315B and third proximal end 305A. In certain embodiments, a third transition portion 308 connects the proximal segment 302 and a top rim 310 at the first proximal end 303A. The third transition portion 308 and / or the top rim 310 may be molded into or bonded to an adapter (e.g., adapter 104 of FIG. 1B). In certain embodiments, the VFC cannula 300 does not include a top rim.

[0051] Similar to the VFC cannula 102, the VFC cannula 300 is configured to be inserted into the valved cannula 220 to inject, evacuate, or extract fluid from the ocular space of a patient's eye through the valved cannula. In certain embodiments, at least a portion of the VFC cannula 300 frictionally engages with an internal feature of the valved cannula 220 when the VFC cannula 300 is inserted therein. For example, at least a portion of the intermediate segment 314 frictionally engages with an internal feature of the valved cannula 220 and / or at least a portion of the distal segment 304 frictionally engages with an interior of the shaft 228, resulting in a "tube-in-tube" configuration between the distal segment 304 and the shaft 228. The tube in tube configuration provides a consistent fluid flow and operating pressure during use of the VFC cannula 300. In certain embodiments, the distal segment 304 of the VFC cannula 300 is sized to closely fit a particular gauge size of the valved cannula 220. For example, the distal segment 304 has an outer diameter configured to fit closely within the shaft 228, such as a 23 gauge valved cannula, a 25 gauge valved cannula, a 27 gauge valved cannula, or the like.

[0052] The different injection cannula may include a unitary body formed of two cylinders of uniform diameter: a wider proximal cylinder and a narrower distal cylinder. The narrower distal cylinder has an ID smaller than that of the shaft 228 of the valved cannula 220. The cylinders are connected by a transition that includes two fillets such that the flow path experiences an abrupt decrease in ID when transitioning between the wider proximal cylinder and the narrower distal cylinder. The abrupt decrease in ID increases the flow resistance therethrough. This transition is located in the overcap 222 of the valved cannula when the different injection cannula is coupled to the valved cannula 220. When coupled, the narrower distal cylinder extends from the overcap 222 through the hub 226 and into the shaft 228 of the valved cannula 220. Thus, different infusion cannulas require fluid flow through a minimum ID at the length that extends from the overcap 222 into the shaft 228, thereby becoming a limiting factor for fluid flow.

[0053] In comparison, VFC cannula 300 is segmented into at least three segments 302, 314, and 304 having three different IDs. In this manner, the different segments (e.g., 314 and 304) may pass through different portions of valved cannula 220 (e.g., hub 226 or shaft 228) when VFC cannula 300 is coupled thereto. Thus, intermediate segment 314 may be disposed within hub 226 and may have an increased inner diameter relative to distal segment 304 within shaft 228, and distal segment 304 having the smallest ID may have a reduced length through shaft 228. The reduced length of distal segment 304 having the smallest ID, in addition to the increased ID within hub 226, beneficially reduces the resistance to fluid flow of VFC cannula 300. Thus, in certain embodiments, a lower source pressure may be used to maintain a given flow rate with embodiments of the VFC cannula disclosed herein, and the source pressure may be reduced in proportion to the reduction in flow resistance.

[0054] In certain embodiments, the distal segment 304 is shorter because a portion of the length of the VFC cannula 300 that extends into the valved cannula 220 is occupied by the middle segment 314, which has a larger ID than the distal segment 304. As shown in FIG. 3B, the length of the VFC cannula 300 that extends into the valved cannula 220 may be the same or shorter than a conventional fluid cannula design. The shorter distal segment 304 generally allows for an increased flow rate of the VFC cannula 300 compared to a conventional cannula design. For example, the shorter distal segment 304 allows for an increased flow rate of about 5-30% or more compared to a conventional fluid cannula design, such as about 8-28% when flowing 1000 cSt (centistokes) silicone oil at 60 psi (pounds per square inch) into the eye. The flow rate is generally affected by the input pressure and viscosity of the fluid flowing through the VFC cannula 300. Flow rate is further affected by the ID of the segment, as narrowing the cross section increases pressure loss, leading to reduced flow rate. Shortening the distal segment 304 reduces the distance the fluid must flow through the smallest ID (e.g., the third ID), providing a longer, wider cross section for the fluid, thereby preventing excessive pressure loss.

[0055] Similar to VFC cannula 102, VFC cannula 300, in certain embodiments, can also include retention features for frictionally engaging internal features of valved cannula 220. For example, intermediate segment 314 can have a recess configured to mate with, closely fit, and / or accommodate recess 232.

[0056] Figures 3C and 3D show isometric and cross-sectional side views, respectively, of VFC cannula 300. In particular, Figure 3D shows the interior profile and internal features of VFC cannula 300, and includes several example dimensions provided in inches unless otherwise noted.

[0057] As shown, proximal segment 302 has a first ID 340, mid segment 314 has a second ID 348, and distal segment 304 has a third ID 342. In certain embodiments, mid segment 314 has an inner dimension, e.g., second ID 348, of about 0.020 inches to about 0.030 inches, e.g., about 0.023 inches to about 0.028 inches, e.g., about 0.023 inches. In certain embodiments, the inner dimension of mid segment 314 is greater than 0.030 inches, such as when the exterior of mid segment 314 fits inside a valved cannula hub (e.g., hub 226 of FIG. 3B) and / or cannula transition (e.g., cannula transition 230 of FIG. 3B) or when distal segment 304 has a recess.

[0058] In certain embodiments, the VFC cannula 300 has an inner shaft length 344 (e.g., distal segment 304, transition section 307, mid-segment 314, and fillet 306B) that may be longer than the inner shaft length 244 of FIG. 2D (e.g., inner shaft length 344 may be about 0.07 inches to about 0.126 inches, e.g., 0.098 inches), and an overall length 346 of about 0.150 inches to about 0.250 inches, e.g., about 0.203 inches. Thus, in some embodiments, the ratio of the inner shaft length 344 to the overall length 346 of the VFC cannula may be about 0.35 to about 0.55, e.g., about (0.098 inches / 0.203 inches=0.483). In certain embodiments, the VFC cannula 300 has an overall width 347 that may be about 0.110 inches to about 0.140 inches, e.g., about 0.126 inches in diameter. Similar to VFC cannula 102, segments 302, 304, and 314 and transition sections 306, 307, and 308 share a common central axis 312 disposed through the center of VFC cannula 300 formed from a single, unitary body. In certain embodiments, proximal segment 302 measures a first length 334, intermediate segment 314 measures a second length 335, and distal segment 304 measures a third length 336, each measured along central axis 312. Third length 336 may be greater than, less than, or equal to second length 335. In further embodiments, third length 336 is zero and VFC cannula 300 has an overall length 346 extending between top rim 310 and a distal end of transition section 307 (e.g., VFC cannula 300 does not include distal segment 304). It should be noted that while features are described herein with particular dimensions or ranges of dimensions, other dimensions and / or IDs are also contemplated.

[0059] In certain embodiments, first transition portion 306 includes first fillet 306A and second fillet 306B, second transition portion 307 includes third fillet 307A and fourth fillet 307B, and third transition portion 308 includes fifth fillet 308A. In certain embodiments, first fillet 306A is concave and second fillet 306B is convex. In certain embodiments, third fillet 307A is concave and fourth fillet 307B is convex. In certain embodiments, fifth fillet 308A is concave, while in other embodiments, fifth fillet 308A is convex. In certain embodiments, the third distal end 305B may include a sixth fillet and / or a second chamfer (e.g., fourth fillet 238 of FIG. 2D ) or a bevel similar to that described in FIG. 2D . The sixth fillet and / or the second chamfer can beneficially facilitate insertion of the VFC cannula 102 into the valved cannula 220 by gradually increasing the outer diameter of the third distal end 305B.

[0060] As shown in FIG. 3D, fillets 306A, 306B, 307A, 307B, and 308A are formed on the inner walls of transition sections 306, 307, and 308. In certain embodiments, fillets are formed on the inner and / or outer walls of transition sections 306, 307, and 308. In certain embodiments, the walls of segments 302, 304, and 314 are configured substantially similarly to the walls of VFC cannula 102 previously described in FIG. 2D. For example, fillets 306A and 306B can have one or more position angles (e.g., position angle 353) referenced to a position of a midpoint of the fillet relative to central axis 312. The position angle can be measured between central axis 312 and a tangent to the midpoint of the fillet. For example, position angle 353 can be between 1 and 85 degrees. For example, position angle 353 can be between 10 and 60 degrees. For example, the position angle 353 may be between 20 degrees and 40 degrees. For example, the position angle 353 may be approximately 26 degrees.

[0061] In certain embodiments, a continuous flow path is formed between the first proximal end 303A and the third distal end 305B of the VFC cannula 300, and the curvature of the transition allows the fluid to flow smoothly through the VFC cannula 300 by reducing frictional losses of the fluid, thereby beneficially improving fluid performance.

[0062] Figures 4A and 4B show isometric and cross-sectional side views of an exemplary infusion cannula 400 coupled to valved cannula 220. In particular, Figures 4A and 4B show the exterior profiles and features of infusion cannula 400 and valved cannula 220. Infusion cannula 400 is configured to be inserted into valved cannula 220 to infuse or evacuate fluid through the valved cannula and into the ocular space of a patient's eye.

[0063] Similar to VFC cannula 300, infusion cannula 400 includes a proximal segment 402, a middle segment 414, and a distal segment 404. Proximal segment 402 includes a first proximal end 403A and a first distal end 403B, middle segment 414 includes a second proximal end 415A and a second distal end 415B, and distal segment 404 includes a third proximal end 405A and a third distal end 405B. A first transition section 406 connects proximal segment 402 and middle segment 414 at first distal end 403B and second proximal end 415A. A second transition section 407 connects middle segment 414 and distal segment 404 at second distal end 415B and third proximal end 405A. A third transition section 408 is configured to connect the proximal segment 402 at the first proximal end 403A with a tubing of an infusion line.

[0064] Similar to VFC cannula 300, in certain embodiments, at least a portion of infusion cannula 400 frictionally engages with internal features of valved cannula 220 when infusion cannula 400 is inserted therein. For example, at least a portion of intermediate segment 414 frictionally engages with internal features of valved cannula 220 and / or at least a portion of distal segment 404 frictionally engages with the interior of shaft 228, resulting in a "tube-in-tube" configuration in which distal segment 404 of infusion cannula 400 may be sized to closely fit a particular gauge size of the valved cannula.

[0065] The different infusion cannula has a unitary body formed of three cylinders of uniform diameter: a wide proximal cylinder, a medium middle cylinder, and a narrow distal cylinder. The medium middle cylinder and the wide proximal cylinder are connected by a transition that includes two fillets, such that the flow path experiences a decrease in ID when transitioning between the medium middle cylinder and the narrow distal cylinder. The sudden decrease in ID increases flow resistance. This transition is located in the overcap 222 of the valved cannula when the different infusion cannula is coupled to the valved cannula 220. Additionally, the narrow distal cylinder has an ID that is smaller than the ID of the shaft 228 of the valved cannula 220. When coupled to the valved cannula, the narrow distal cylinder extends into the shaft 228 of the valved cannula. Therefore, the transitions between the wide proximal segments and the medium intermediate and extended distal segments of different infusion cannulas become a limiting factor for fluid flow as they require fluid flow through a minimum ID at the length extending from the overcap 222 into the shaft 228.

[0066] In comparison, infusion cannula 400 is segmented into at least three segments 402, 414, and 404 having three different IDs. In this manner, the different segments (e.g., 414 and 404) may pass through different portions of valved cannula 220 (e.g., hub 226 or shaft 228) when infusion cannula 400 is coupled thereto. Thus, intermediate segment 414 within hub 226 may have an increased inner diameter relative to distal segment 404 within shaft 228, and distal segment 404, having the smallest ID, may have a reduced length through shaft 228.

[0067] 4B, the distal segment 404 is shorter because the extended distal segment of a conventional infusion cannula restricts fluid flow. The shorter distal segment 404 prevents excessive pressure loss by reducing the distance the fluid must flow through the minimum ID (e.g., the third ID) and providing a longer, wider cross-section of the shaft 228 for the fluid to flow through. Thus, in certain embodiments, a lower source pressure may be used to maintain a given flow rate with embodiments of the infusion cannulas disclosed herein, and the source pressure may be reduced in proportion to the reduction in flow resistance.

[0068] Additionally, the configuration of first transition portion 406 can improve fluid flow through infusion cannula 400. In certain embodiments, first transition portion 406 includes a chamfer (e.g., first chamfer 406C in FIG. 4D ) that forms a funnel-shaped feature in infusion cannula 400 with a gradual decrease in ID between proximal segment 402 and intermediate segment 414. The chamfer facilitates preventing excessive pressure loss compared to conventional infusion cannula transitions by providing a gradual, linearly decreasing reduction in cross section for the fluid.

[0069] The shorter distal segment 304 and the addition of a chamfer to the first transition 406 can generally increase the flow rate and proportionately decrease the pressure drop within the infusion cannula 400 as compared to conventional infusion or injection cannula designs. For example, in certain embodiments, the flow rate is increased by about 5% to about 30% or more and the pressure drop is decreased proportionately, e.g., by about 20% to about 35% or more, as compared to conventional cannula designs. As discussed above, the flow rate and pressure drop are affected by the segment ID, as well as the source pressure and fluid viscosity.

[0070] In certain embodiments, infusion cannula 400 includes retention features for frictionally engaging with internal features of valved cannula 420. For example, intermediate segment 414 may have a recess configured to mate with, closely match, and / or accommodate recess 232.

[0071] Figures 4C and 4D show isometric and cross-sectional side views, respectively, of infusion cannula 400. In particular, Figure 4C shows the interior profile and features of infusion cannula 400, and Figure 4D includes several example dimensions, provided in inches unless otherwise noted.

[0072] As shown, proximal segment 402 has a first ID 440, mid segment 414 has a second ID 448, and distal segment 404 has a third ID 442. In certain embodiments, mid segment 414 has an inner dimension, e.g., second ID 448, of about 0.020 inches to about 0.030 inches, e.g., about 0.023 inches to about 0.028 inches, e.g., about 0.028 inches. In certain embodiments, the inner dimension of mid segment 414 is greater than 0.030 inches, such as when the exterior of mid segment 414 fits inside a valved cannula hub (e.g., hub 226 of FIG. 3B) and / or cannula transition (e.g., cannula transition 230 of FIG. 3B) or when distal segment 404 has a recess.

[0073] In certain embodiments, infusion cannula 400 has a midshaft length 450 of about 0.050 inches to about 0.130 inches, such as about 0.060 inches to about 0.111 inches, such as about 0.065 inches. In certain embodiments, infusion cannula 400 has an overall length 446 of about 0.320 inches to about 0.400 inches, such as about 0.325 inches to about 0.385 inches, such as about 0.338 inches. In certain embodiments, infusion cannula 400 has a width 447, which may be about 0.080 inches to about 0.110 inches, such as about 0.092 inches in diameter. Similar to VFC cannula 300 previously described in FIG. 3D, segments 402, 404, and 414 and transitions 406, 407, and 408 share a common central axis 412 disposed through the center of infusion cannula 400 formed from a single, unitary body. In certain embodiments, the proximal segment 402 measures a first length 434, the intermediate segment 414 measures a second length 435, and the distal segment 404 measures a third length 436, each measured along the central axis 412. The third length 436 may be greater than, less than, or equal to the second length 435. In some embodiments, the third length 436 may be between about 0.020 inches and about 0.100 inches, such as between about 0.035 inches and about 0.08 inches, such as about 0.050 inches. Thus, in some embodiments, the ratio between the third length 436 and the overall length 446 may be between about 0.05 and 0.25, such as about 0.050 inches / 0.338 inches=0.148. In some embodiments, the ratio between the midshaft length 450 and the overall length 446 may be between about 0.08 and 0.28, for example, about 0.065 inches / 0.338 inches=0.192.

[0074] In some embodiments, the sum of the mid-shaft length 450 and the third length 436 may be between about (0.05 inches + 0.02 inches = 0.07 inches) and about (0.130 inches + 0.100 inches = 0.230 inches), such as between about (0.060 inches + 0.035 inches = 0.095 inches) and about (0.111 inches + 0.08 inches = 0.191 inches), such as about (0.065 inches + 0.050 inches = 0.115 inches). Thus, in some embodiments, the ratio of the sum of the mid-shaft length 450 and the third length 436 to the overall length 446 may be between about 0.2 and 0.4, such as about (0.115 inches / 0.338 inches = 0.340). It is noted that while features are described herein with particular dimensions or ranges of dimensions, other dimensions and / or IDs are also contemplated.

[0075] As shown in FIGURE 4D, first transition portion 406 includes first fillet 406A, first chamfer 406C, and fifth fillet 406B, second transition portion 407 includes second fillet 407A and third fillet 407B, and third transition portion 408 includes fourth fillet 408A. Fillets 406A, 406B, 407A, 407B, and 408A and chamfer 406C are formed on the inner walls of transition portions 406, 407, and 408, but in further embodiments, are formed on the inner and / or outer walls of transition portions 406, 407, and 408. In certain embodiments, fillets 406A, 406B, 407A, 407B, and 408A are configured substantially similar to the fillets of VFC cannula 300 previously described in FIGURE 3D. In certain embodiments, the first chamfer 406C is used in place of the first fillet 406A and / or the fifth fillet 406B. In certain embodiments, the first transition portion 406 includes a second chamfer in place of the fifth fillet 406B. In certain embodiments, the transition angle θ (e.g., the first transition angle 452 in FIG. 4D ) is measured between the first chamfer 406C and an axis of one of the segments 402, 404, or 414, which may not be collinear with the central axis 412. In certain embodiments, the transition angle θ is measured between the first chamfer 406C and the central axis 412. In certain embodiments, the transition angle θ is between about 150 degrees and about 170 degrees, such as about 161 degrees, although in further embodiments, the transition angle θ may be about 90 degrees, including up to about 165 degrees. In further embodiments, the transition angle θ is greater than 90 degrees. In certain embodiments, chamfer angle α is measured between the second chamfer and one of the previously described axes (e.g., central axis 412). In certain embodiments, chamfer angle α is greater than transition angle θ. In certain embodiments, the walls of segments 402, 404, and 414 are configured substantially similarly to the walls of VFC cannula 300 previously described in FIG. 3D.

[0076] In certain embodiments, the first transition portion 406 includes a first chamfer or bevel (e.g., first chamfer 406C of FIG. 4D ) as described in FIG. 4D . In certain embodiments, the third distal end 405B includes a sixth fillet (e.g., fourth fillet 238 of FIG. 2D ) and / or a second chamfer or bevel similar to that described in FIG. 2D . The sixth fillet and / or second chamfer can beneficially facilitate insertion of the VFC cannula 102 into the valved cannula 220 by gradually increasing the outer diameter of the third distal end 305B.

[0077] In certain embodiments, the second transition portion 407 includes a third chamfer or bevel that is disposed in a similar manner as the first chamfer 406C, but relative to the fillets 407A and 407B.

[0078] In certain embodiments, a continuous flow path is formed between the first proximal end 403A and the third distal end 405B of the infusion cannula 400, and the curvature of the transition allows the fluid to flow smoothly through the infusion cannula 400 by reducing frictional losses of the fluid, thereby beneficially improving fluid performance.

[0079] In summary, embodiments of the present disclosure include fluid cannulas for improving fluid administration and fluid flow during ophthalmic surgical procedures. For example, embodiments described herein provide efficient administration of ocular infusion fluids and tamponade, thereby facilitating improved intraocular pressure maintenance. The described cannula assemblies include embodiments in which the minimum inner diameter (ID) of the cannula is greater than the ID of the shaft of a corresponding valved cannula. As described in further detail below, a larger cannula ID reduces overall flow resistance and pressure loss through the improved fluid cannula, increasing flow rate at a given source pressure. The cannula assemblies further include embodiments in which the cannula includes a middle segment having an ID greater than the ID of the valved cannula shaft, a distal segment that extends a reduced distance into the valved cannula shaft, and a smooth transition between the middle and distal segments. The cannula assemblies further include embodiments in which the cannula includes a chamfer or bevel at the transition between the proximal and middle segments of the cannula such that the transition is funnel-shaped. The above-described cannulas are therefore particularly beneficial during injection, extraction, infusion and evacuation of fluids into and / or from the eye, where reduced fluid resistance allows for less operating pressure to achieve a given flow rate.

[0080] Exemplary embodiments Embodiment 1: A cannula device for a surgical procedure comprising: a proximal segment including a first inner diameter (ID), a first proximal end, and a first distal end; and a distal segment including a second ID smaller than the first ID, a second proximal end, and a second distal end configured to be positioned within a hub or cannula transition of a valved cannula including a hub, a shaft, and a cannula transition between the hub and shaft.

[0081] Embodiment 2: A cannula device as described in embodiment 1 above, wherein the second distal end further includes a fourth fillet or a second chamfer.

[0082] Embodiment 3: A cannula device as described in embodiment 2 above, wherein a fourth fillet or a second chamfer is formed on the inner or outer wall of the distal segment.

[0083] Embodiment 4: A cannula device as described in embodiment 3 above, wherein the proximal segment and the distal segment share a common central axis of the cannula device.

[0084] Embodiment 5: A cannula device as described in embodiment 3 above, further comprising a first transition portion connecting the proximal segment and the distal segment via a first distal end and a second proximal end, the first transition portion including a first fillet and a second fillet.

[0085] Embodiment 6: A cannula device as described in embodiment 5 above, wherein the first fillet is concave and the second fillet is convex.

[0086] Embodiment 7: A cannula device as described in embodiment 5 above, wherein a first fillet and / or a second fillet are formed on the inner wall or outer wall of the first transition portion.

[0087] Embodiment 8: A cannula device as described in embodiment 5 above, wherein the first transition portion further includes a first chamfer disposed between the first fillet and the second fillet.

[0088] Embodiment 9: A cannula device as described in embodiment 8 above, wherein a first chamfer is formed on the inner or outer wall of the first transition portion.

[0089] Embodiment 10: A cannula device as described in embodiment 5 above, further comprising a second transition portion connecting to the first proximal end, the second transition portion including a third fillet.

[0090] Embodiment 11: A cannula device as described in embodiment 10 above, wherein the third fillet is concave or convex.

[0091] Embodiment 12: A cannula device as described in embodiment 10 above, wherein a third fillet is formed on the inner or outer wall of the second transition portion.

[0092] Embodiment 13: A cannula device as described in embodiment 10 above, wherein a second transition portion connects the proximal segment to a tube of a syringe adapter or an infusion line.

[0093] Embodiment 14: A cannula device as described in embodiment 5 above, wherein the proximal segment and the distal segment share a common central axis of the cannula device.

[0094] Embodiment 15: A cannula device as described in embodiment 14 above, wherein the first transition portion and / or the second transition portion share a common central axis of the cannula device.

[0095] Embodiment 16: A cannula device as described in embodiment 14 above, wherein the first transition portion further includes a first chamfer disposed between the first fillet and the second fillet.

[0096] Embodiment 17: A cannula device as described in embodiment 16 above, wherein the first chamfer defines a transition angle between the first chamfer and the common central axis, the transition angle measuring approximately 161 degrees.

[0097] Embodiment 18: A cannula device as described in embodiment 5 above, wherein the first transition portion further includes a first chamfer disposed between the first fillet and the second fillet.

[0098] Embodiment 19: A cannula device for surgical procedures, comprising: a proximal segment including a first inner diameter (ID), a first proximal end, and a first distal end; an intermediate segment including a second ID smaller than the first ID, a second proximal end, and a second distal end; a first transition portion connecting the proximal segment and the intermediate segment via the first distal end and the second proximal end, the first transition portion including a first fillet; a distal segment including a third ID smaller than the second ID, a third proximal end, and a third distal end; and a second transition portion connecting the intermediate segment and the distal segment via the second distal end and the third proximal end, the second transition portion including a third fillet and a fourth fillet.

[0099] Embodiment 20: A cannula device as described in embodiment 19 above, wherein the first fillet is concave and the second fillet is convex.

[0100] Embodiment 21: A cannula device as described in embodiment 19 above, wherein the first transition portion further includes a second chamfer or a second fillet.

[0101] Embodiment 22: A cannula device as described in embodiment 21 above, wherein the first transition portion further includes a first chamfer disposed between the first fillet and the second chamfer or the second fillet.

[0102] Embodiment 23: A cannula device as described in embodiment 22 above, wherein the proximal segment and the distal segment share a common central axis of the cannula device.

[0103] Embodiment 24: A cannula device as described in embodiment 23 above, wherein the first chamfer defines a transition angle between the first chamfer and a central axis of the device, the transition angle measuring between about 90 degrees and about 165 degrees.

[0104] Embodiment 25: The cannula device described in embodiment 19 above, further comprising an inner shaft length of about 0.050 inches to about 0.098 inches.

[0105] Embodiment 26: A cannula device as described in embodiment 21 above, wherein a first fillet, a second fillet, and / or a second chamfer are formed on the inner or outer wall of the first transition portion.

[0106] Embodiment 27: A cannula device as described in embodiment 21 above, wherein the first transition portion further includes a first chamfer disposed between the first fillet and the second fillet.

[0107] Embodiment 28: A cannula device as described in embodiment 27 above, wherein a first chamfer is formed on the inner or outer wall of the first transition portion.

[0108] Embodiment 29: A cannula device as described in embodiment 19 above, wherein the third fillet is concave and the fourth fillet is convex.

[0109] Embodiment 30: A cannula device as described in embodiment 19 above, wherein a third fillet and / or a fourth fillet are formed on the inner or outer wall of the second transition portion.

[0110] Embodiment 31: A cannula device as described in embodiment 19 above, further comprising a third transition portion connecting to the first proximal end, the third transition portion including a fifth fillet.

[0111] Embodiment 32: A cannula device as described in embodiment 31 above, wherein the fifth fillet is concave or convex.

[0112] Embodiment 33: A cannula device as described in embodiment 31 above, wherein a fifth fillet is formed on the inner or outer wall of the third transition section.

[0113] Embodiment 34: A cannula device as described in embodiment 31 above, wherein a third transition portion connects the proximal segment to a tube of a syringe adapter or an infusion line.

[0114] Embodiment 35: A cannula device as described in embodiment 19 above, wherein the third distal end is configured to be positioned inside a valved cannula having a hub and a shaft, and at least a portion of the distal segment is configured to frictionally engage with an inner surface of the valved cannula.

[0115] Embodiment 36: A cannula device as described in embodiment 35 above, wherein at least a portion of the intermediate segment is configured to frictionally engage with the interior of the hub of the valved cannula.

[0116] Embodiment 37: A cannula device as described in embodiment 35 above, wherein at least a portion of the intermediate segment is configured to frictionally engage with an internal recess of the valved cannula.

[0117] Embodiment 38: A cannula device as described in embodiment 19 above, wherein the proximal segment, the distal segment, the first transition portion, and / or the second transition portion share a common central axis of the cannula device.

[0118] Embodiment 39: A cannula device as described in embodiment 31 above, wherein the proximal segment, the distal segment, the first transition portion, the second transition portion, and / or the third transition portion share a common central axis of the cannula device.

[0119] Embodiment 40: A cannula device as described in embodiment 19 above, wherein the third distal end further includes a sixth fillet or a second chamfer.

[0120] Embodiment 41: A cannula device described in embodiment 40 above, wherein a sixth fillet or a second chamfer is formed on the inner or outer wall of the distal segment.

[0121] The above description is provided to enable those skilled in the art to practice the various embodiments described herein. The examples described herein are not intended to limit the scope, applicability, or embodiments described in the claims. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applicable to other embodiments. For example, changes may be made in the function and arrangement of the elements discussed without departing from the scope of the disclosure. In various examples, various procedures or components may be omitted, substituted, or added, as appropriate. For example, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Also, features described with respect to some examples may be combined in some other examples. For example, an apparatus may be implemented or a method may be practiced using any number of aspects described herein. Furthermore, the scope of the disclosure is intended to cover such apparatus or methods implemented using other structures, functions, or structures and functions in addition to or other than the various aspects of the disclosure described herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim.

[0122] As used herein, the word "exemplary" means "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects.

[0123] As used herein, a phrase referring to "at least one of" a list of items refers to any combination of those items, including a single element. By way of example, "at least one of a, b, or c" is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination of multiples of the same elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc or any other permutation of a, b, and c).

[0124] The following claims are not intended to be limited to the embodiments set forth herein, but are to be accorded the full scope consistent with the language of the claims. In the claims, reference to an element in the singular is not intended to mean "one and only one" unless specifically so specified, but rather "one or more." Unless specifically specified otherwise, the term "some" refers to one or more. No element of a claim is to be construed under the provisions of 35 U.S.C. 112(f) unless the element is expressly recited using the phrase "means for" or, in the case of a method claim, the element is recited using the phrase "step for." All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later become known to those of skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed in this specification is intended to be dedicated to the public, regardless of whether such disclosure is expressly recited in the claims.

Claims

1. A cannula device for surgical procedures, a proximal segment including a first inner diameter (ID), a first proximal end, and a first distal end, and a distal segment including a second ID smaller than the first ID, a second proximal end, and a second distal end configured to be disposed inside the hub or the cannula transition portion between the hub and the shaft of the cannula with a valve, wherein the proximal segment and the distal segment have a common central axis disposed through the center of the cannula device, a first transition portion connecting the proximal segment and the distal segment via the first distal end and the second proximal end includes a first concave fillet and a second convex fillet, wherein a ratio of the length of the distal segment to the overall length of the cannula device is within a range of about 0.2 to 0.4, and a positional angle between the central axis and a tangent passing through the midpoint of the first concave fillet is within a range of about 20 degrees to 40 degrees. A cannula device.

2. The cannula device according to claim 1, wherein the ratio of the length of the distal segment to the overall length of the cannula device is about 0.

325.

3. The cannula device according to claim 1, wherein the positional angle is about 26 degrees.

4. The cannula device according to claim 1, wherein the shaft has a third ID smaller than the second ID.

5. The cannula device according to claim 1, wherein at least a portion of the distal segment is configured to frictionally engage with the inner surface of the cannula with a valve.

6. The cannula device according to claim 5, wherein the distal segment is configured to frictionally engage with the inner surface of the hub or the cannula transition portion of the cannula with a valve.

7. The cannula device according to claim 1, further comprising a second transition portion connecting to the first proximal end and including a third fillet.

8. The cannula device according to claim 1, wherein the second distal end further includes a fourth fillet or a second chamfer.

9. A cannula device for surgical procedures, a proximal segment including a first inner diameter (ID), a first proximal end, and a first distal end, and an intermediate segment including a second ID smaller than the first ID, a second proximal end, and a second distal end. A first transition portion connecting the proximal segment and the intermediate segment via the first distal end and the second proximal end, the first transition portion including a first concave fillet and a second convex fillet; A distal segment including a third ID smaller than the second ID, a third proximal end, and a third distal end; A second transition portion connecting the intermediate segment and the distal segment via the second distal end and the third proximal end, the second transition portion including a third fillet and a fourth fillet; The proximal segment, the intermediate segment, and the distal segment have a common central axis disposed through the center of the cannula device; The distal segment, the second transition portion, the intermediate segment, and the second convex fillet have an overall internal shaft length; The ratio of the overall internal shaft length to the overall length of the cannula device is within a range of about 0.35 to 0.55; A cannula device, wherein the positional angle between the central axis and a tangent line passing through the midpoint of the first concave fillet is within a range of about 20 degrees to 40 degrees. **Claim 10** The cannula device according to claim 9, wherein the ratio of the overall internal shaft length to the overall length of the cannula device is about 0.

483. **Claim 11** The cannula device according to claim 9, wherein the third distal end is configured to be disposed inside a cannula with a valve having a hub and a shaft, and at least a portion of the distal segment is configured to be in frictional engagement with the inner surface of the cannula with the valve. **Claim 12** The cannula device according to claim 9, further comprising a third transition portion connecting to the first proximal end, the third transition portion including a fifth fillet. **Claim 13** The cannula device according to claim 9, wherein the first transition portion further includes a first chamfer disposed between the first concave fillet and a second chamfer or the second convex fillet. **Claim 14** The cannula device according to claim 9, wherein the third distal end further includes a sixth fillet or a second chamfer. **Claim 15** An injection cannula device for a surgical procedure, A proximal segment including a first inner diameter (ID), a first proximal end, and a tapered first distal end; An intermediate segment including a second ID smaller than the first ID, a second proximal end, and a second distal end; A first transition portion connecting the proximal segment and the intermediate segment via the first distal end and the second proximal end; A distal segment including a third ID smaller than the second ID, a third proximal end, and a third distal end; A second transition portion connecting the intermediate segment and the distal segment via the second distal end and the third proximal end, the second transition portion including a third fillet and a fourth fillet; The proximal segment, the intermediate segment, and the distal segment have a common central axis disposed through the center of the infusion cannula device; The distal segment and the intermediate segment have a first internal shaft length; The distal segment, the intermediate segment, and the proximal segment have an overall internal shaft length; An infusion cannula device, wherein a ratio of the first internal shaft length to the overall internal shaft length of the infusion cannula device is in a range of about 0.2 to 0.

4. **Claim 16**: A system of a cannula device for a surgical procedure, A cannula with a valve including a hub, a shaft, and a cannula transition portion between the hub and the shaft; A viscous fluid control (VFC) cannula, A proximal segment including a first inner diameter (ID), a first proximal end, and a first distal end; A distal segment including a second ID smaller than the first ID, a second proximal end, and a second distal end terminating inside the hub of the cannula with a valve, the distal segment having a gap formed between the distal segment and the hub such that when the intraocular pressure is higher than the pressure exerted by the infused fluid, the infused fluid can flow back from the cannula with a valve; A viscous fluid control (VFC) cannula including; Comprising; The proximal segment and the distal segment have a common central axis disposed through the center of the VFC cannula; A first transition portion connecting the proximal segment and the distal segment via the first distal end and the second proximal end includes a first concave fillet and a second convex fillet connected by a first chamfer; A system of a cannula device, wherein a transition angle between the first chamfer and the common central axis is in a range of about 90 degrees to 165 degrees.

17. The system of the cannula device according to claim 16, wherein the ratio of the length of the distal segment to the total length of the VFC cannula is about 0.

325.

18. The system of the cannula device according to claim 16, wherein the transition angle of the VFC cannula is about 120 degrees.

19. The system of the cannula device according to claim 16, wherein the shaft of the cannula with valve includes a third ID that is smaller than the second ID.

20. The system of the cannula device according to claim 16, wherein at least a portion of the distal segment of the VFC cannula is configured to frictionally engage with the inner surface of the cannula with valve.

21. The system of the cannula device according to claim 20, wherein the distal segment of the VFC cannula is configured to frictionally engage with the inner surface of the hub or the cannula transition portion of the cannula with valve.

22. The system of the cannula device according to claim 16, wherein the VFC cannula further includes a second transition portion that connects to the first proximal end, and the second transition portion includes a third fillet.

23. The system of the cannula device according to claim 16, wherein the second distal end of the VFC cannula further includes a fourth fillet or a second chamfer.

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