Occlusion detection in vacuum-based ophthalmic surgical systems

Abstract

An occlusion detection system for a vacuum-based ophthalmic surgical system includes a handpiece, as well as an aspiration subsystem and an irrigation subsystem. The aspiration subsystem includes an aspiration line connected to the handpiece, an aspiration pressure transducer, and a vacuum-based aspiration pump. The irrigation subsystem includes an irrigation line connected to an irrigation fluid source having irrigation fluid, the handpiece, the irrigation pressure transducer, and a positive displacement pump. The system also includes a processor coupled to the positive displacement pump and a memory coupled to the processor. The memory includes executable instructions for the processor to determine a flow rate of irrigation fluid through the irrigation line based on a rotational speed of the positive displacement pump, and to provide an occlusion warning to a user when the flow rate falls below a threshold level and a vacuum is commanded.

Description

[Technical Field]

[0001] The present disclosure relates generally to vacuum-based ophthalmic surgical systems, and more particularly to vacuum-based ophthalmic surgical systems having positive displacement irrigation pumps with occlusion detection. [Background technology]

[0002] This section provides background information related to the present disclosure that is not necessarily prior art.

[0003] Ophthalmic surgery often involves resecting or emulsifying tissue that needs to be removed from the eye, such as in cataract surgery. One known technique is phacoemulsification, which involves using high-frequency ultrasonic energy to transmit through a handpiece to the tip of a phacoemulsification needle to emulsify the affected tissue. Typically, the handpiece is connected to an irrigation fluid source (e.g., an elevated saline bottle) and an aspiration pump. During surgery, saline is introduced into the eye from the irrigation fluid source through the handpiece to maintain the eye under pressure and to aid in the aspiration of the emulsified tissue. Once the tissue has been emulsified by the phacoemulsification needle, the saline and emulsified tissue are aspirated from the eye through the handpiece by the aspiration pump.

[0004] One type of aspiration pump is a vacuum-based pump, such as a Venturi pump. During operation, a vacuum-based pump indirectly controls fluid flow by controlling the vacuum. Vacuum-based systems generally use vacuum to draw fluid through the aspiration line (as opposed to aspiration using a positive displacement pump, e.g., a peristaltic pump). In such systems, as the vacuum increases, the aspiration rate similarly increases. For example, a vacuum-based pump creates a pressure within the drainage cassette that is lower than the intraocular pressure (IOP), forcing fluid from the eye into the cassette. Another type of aspiration pump is a positive displacement pump, typically a peristaltic pump, which draws fluid through the aspiration line by periodically pinching tubing between a series of rollers. As the tubing contracts and then expands, a vacuum / suction force is created, drawing fluid through the tubing. Knowing the tubing material, the inner diameter of the tubing, the number of rollers pinching the tubing, and the speed at which the rollers rotate can be used to calculate the rate at which fluid flows through the tubing.

[0005] Under normal surgical conditions, the flow rate of saline infused into the eye closely matches the flow rate of emulsified tissue and saline aspirated from the eye, resulting in a stable fluid volume in the anterior chamber of the eye. Rarely, during surgery, the handpiece (e.g., phaco tip) may become blocked by aspirated material, blocking the aspiration flow and resulting in blocked irrigation fluid flow and / or elevated IOP.

[0006] After the material that was blocking the phaco tip is removed, a phenomenon called post-occlusion surge can occur. Post-occlusion surge occurs when fluid flows into the aspiration port after the material that was blocking the phaco tip is removed, filling the vacuum in the tubing and subsequently causing a decrease in intraocular pressure, which can lead to surgical complications. For example, post-occlusion surge can cause the anterior chamber to shallow or the iris or posterior capsule to move toward the phaco emulsification tip, increasing the risk of posterior capsule rupture or iris trauma.

[0007] Traditionally, there is only one method for detecting blockages during ophthalmic surgery, and this method is only available in systems that use positive displacement pumps (as opposed to, for example, vacuum-based pumps) for aspiration flow. In such systems, the aspiration peristaltic pump stops when the maximum vacuum setting is reached, assuming the handpiece is blocked. In this case, a blockage warning can be provided to the surgeon. Using this method, the surgeon can choose to stop powering the handpiece, minimizing the risk of surgical complications. Vacuum-based ophthalmic surgery systems, on the other hand, only control the vacuum level and simply maintain a set or commanded vacuum level in the aspiration path. Because the flow rate through the system is based on the vacuum level, the resulting flow rate is variable and not monitored. Therefore, vacuum-based systems generally cannot detect blockages when they occur. Summary of the Invention

[0008] This section provides an overview of the disclosure and is not a comprehensive disclosure of its entire scope or all of its functionality.

[0009] Exemplary embodiments of the present disclosure generally relate to a vacuum-based system for ophthalmic surgery, including occlusion detection. In one exemplary embodiment, the system includes a processor, a memory coupled to the processor, a handpiece coupled to the processor, an aspiration subsystem operably coupled to the handpiece, and an irrigation subsystem operably coupled to the handpiece. The aspiration subsystem includes a vacuum-based aspiration pump, an aspiration line coupled to the handpiece and the vacuum-based aspiration pump, and an aspiration pressure transducer operably coupled to the aspiration line and the processor for sensing pressure in the aspiration line. The irrigation subsystem includes an irrigation fluid source having irrigation fluid, an irrigation line coupled to the handpiece and the irrigation fluid source, a positive displacement pump operably coupled to the irrigation line between the irrigation fluid source and the handpiece, the positive displacement pump operably coupled to the processor, and a pressure transducer coupled to the irrigation line for sensing irrigation pressure in the irrigation line, the pressure transducer operably coupled to the processor. The memory includes executable instructions that, when executed by the processor, cause the processor to determine a flow rate of irrigation fluid through the irrigation line based on at least the rotational speed of the positive displacement pump and the pressure sensed by the pressure transducer, determine whether a vacuum is being commanded by the vacuum-based aspiration pump, and provide an occlusion warning to a user if the irrigation flow rate falls below a threshold level and a vacuum is being commanded.

[0010] In another exemplary embodiment, a method for providing occlusion detection in a vacuum-based ophthalmic surgical system is provided. The method includes receiving, by a computing device, operational data from a positive displacement pump and pressure data from an irrigation transducer. Both the positive displacement pump and the irrigation transducer are operably coupled to an irrigation line. The irrigation line also connects a handpiece to an irrigation fluid source. The method further includes determining, by the computing device, whether a vacuum is commanded to a vacuum-based aspiration pump coupled to the handpiece; calculating, by the computing device, an irrigation flow rate of irrigation fluid through the irrigation line based on the operational data and the pressure data; comparing, by the computing device, the calculated irrigation flow rate to a threshold; and providing, by the computing device, an occlusion warning to a user if the irrigation flow rate does not meet the threshold and a vacuum is commanded.

[0011] Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

[0012] The drawings described herein are for purposes of illustrating selected embodiments only, do not depict all possible implementations, and are not intended to limit the scope of the present disclosure. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a block diagram of an exemplary embodiment of a vacuum-based ophthalmic surgical system with occlusion detection; [Figure 2] Block diagram of a method for detecting occlusions in a vacuum-based ophthalmic surgical system DETAILED DESCRIPTION OF THE INVENTION

[0014] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

[0015] Exemplary embodiments of the present disclosure generally relate to vacuum-based systems for ophthalmic surgery. Current vacuum-based ophthalmic surgical systems use a vacuum-based pump to aspirate fluids and other materials from the eye through an aspiration line, while fluid supplied from an irrigation fluid source is irrigated into the eye through an irrigation line. In such systems, the pressure in the irrigation line (and resulting irrigation flow rate) is independent of the vacuum generated by the vacuum-based pump, and occlusion detection is generally not available in vacuum systems. Uniquely, the disclosed system integrates an irrigation pump with an irrigation-side pressure transducer (e.g., operably coupled to the irrigation line, etc.) to generate a flow of irrigation fluid into the eye at a set irrigation pressure that is independent and separate from the aspiration flow of fluid from the eye generated by the vacuum-based pump. In this way, the aspiration flow rate is controlled by the vacuum-based pump, and the irrigation flow rate is independently controlled by a positive displacement pump. By placing a positive displacement pump and pressure transducer in the irrigation pathway, a set irrigation pressure can be maintained regardless of the saline flow rate (i.e., aspiration) from the eye. The pressure on the perfusion side (e.g., via a pressure transducer, etc.) as well as the operating state of the pump (e.g., rotational speed / speed (rpm), etc.) can be monitored to determine the perfusion flow rate. If the flow rate falls below a threshold when the surgeon is commanding vacuum (e.g., foot pedal, console input, etc.), it is determined that an occlusion has likely occurred and an occlusion alert is provided to the surgeon. Occlusion detection can be provided to vacuum-based systems by introducing a positive displacement pump on the perfusion side.

[0016]

[0013] Exemplary embodiments will now be described in more detail with reference to the accompanying drawings. The description and specific examples contained herein are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

[0017] 1 illustrates an exemplary embodiment of an ophthalmic surgical system 100 incorporating one or more aspects of the present disclosure. In the illustrated embodiment, the system 100 generally includes a handpiece 102 (e.g., a phacoemulsification handpiece, etc.), an irrigation fluid source 104, and a vacuum source 106. On the irrigation side of the system 100 (broadly, the irrigation subsystem), the irrigation fluid source 104 (e.g., an elevated bottle / bag of saline solution, etc.) is in fluid communication with the handpiece 102 by an irrigation line 108. The irrigation fluid source 104 is configured to supply saline solution (broadly, the irrigation fluid) to the system 100. The irrigation fluid source 104 is coupled to a first end of the irrigation line 108, and the handpiece 102 is connected to a second end of the irrigation line 108. The irrigation subsystem also includes a positive displacement pump 116 operably coupled to an irrigation line 108 between the irrigation fluid source 104 and the handpiece 102, and a pressure transducer 118 coupled to the irrigation line 108 for sensing irrigation pressure within the irrigation line 108. On the aspiration side of the system 100 (broadly the aspiration subsystem), a vacuum source 106 (e.g., a vacuum-based aspiration pump, etc.) is in fluid communication with the handpiece 102 by way of an aspiration line 110 and an aspiration pressure transducer 114 for sensing pressure within the aspiration line 110. The vacuum source 106 is configured to generate vacuum / suction to move fluid through the system 100 (e.g., to aspirate fluid from the eye 10 through the aspiration line 110). The vacuum source 106 is coupled to a first end of the irrigation line 110, the handpiece 102 is connected to a second end of the aspiration line 110, and the aspiration pressure transducer is positioned in communication with the aspiration line 110 between the vacuum source 106 and the handpiece 102.

[0018] The handpiece 102 includes a phacoemulsification needle 112 having a tip configured to be inserted into the eye 10 during surgery. The handpiece 102 also includes a vibration source (not shown) configured to sonicate or ultrasonically vibrate the needle 112. The needle 112 is configured to emulsify tissue within the eye 10 when vibrated by the vibration source (e.g., a piezoelectric stack, etc.). To maintain intraocular pressure and aid in aspirating emulsified material from the eye 10, saline from an irrigation fluid source 104 is irrigated into the eye 10 through one or more ports in a sleeve (not shown) surrounding the needle 112. The saline, along with the emulsified material, is aspirated from the eye 10 by a vacuum source 106.

[0019] The vacuum source 106 includes a vacuum-based pump, such as a Venturi pump. The vacuum source 106 is configured to generate a vacuum (broadly, an aspiration flow) that draws fluid from the eye 10 through an aspiration line 110 and into a drainage cassette (not shown). To monitor the vacuum level within the aspiration line 110, the system 100 also includes an aspiration pressure transducer 114 in communication with the aspiration line 110. The aspiration pressure transducer 114 is used in connection with setting the desired vacuum level of the vacuum source 106.

[0020] As part of the irrigation subsystem, system 100 also includes components for detecting occlusions. In particular, system 100 includes a positive displacement pump 116 that generates a fluid flow (broadly referred to as the irrigation flow rate or flow rate) through irrigation line 108 and a pressure transducer 118 that monitors the pressure within irrigation line 108. Pump 116 is coupled to irrigation line 108 between irrigation fluid source 104 and handpiece 102. Pressure transducer 118 is coupled to irrigation line 108 between pump 116 and handpiece 102. In the illustrated embodiment, pump 116 is a peristaltic pump. However, in other embodiments, other positive displacement pumps may be used (e.g., rotary, reciprocating, linear, etc.). In system 100, the settings on the irrigation side of system 100, such as the infusion pressure (e.g., the pressure detected by pressure transducer 118), are set independently of the settings on the aspiration side of system 100 (e.g., the vacuum setting of vacuum source 106). For example, the irrigation flow rate of the irrigation line 108 is controlled independently and separately from the aspiration flow rate of the aspiration line 110 .

[0021] A processor / computing device 120 (e.g., processor, controller, etc.) is operably coupled to the handpiece 102 (not shown), the vacuum source 106, the aspiration pressure transducer 114, the pump 116, and the irrigation pressure transducer 118, as shown. The processor 120 is typically housed in a surgical console, which may also house the vacuum source 106 and the pump 116, and may also include the transducers 114, 118. The computing device 120 is configured to execute (e.g., via executable instructions contained in memory 121, etc.) configuration of the aspiration subsystem (e.g., vacuum level, etc.) and the irrigation subsystem (e.g., setting the irrigation pressure of the fluid in the irrigation line 108, etc.). For a given irrigation line material, inner diameter, number of rollers 117, and rotation radius of the rollers 117 of the pump 116, a known amount of fluid is aspirated each time the rollers pinch the line 108 and then retract from the pinched position; this amount can be obtained from the pump manufacturer or empirically obtained through testing. From this known information stored in memory 121 and sensing the pressure and rotational speed of the rollers 117, the irrigation flow rate can be calculated and monitored. The computing device 120 is also configured to control the function of components of the system 100 (e.g., handpiece 102 (connections not shown), vacuum source 106, etc.) based on input(s) received, for example, from a foot pedal (not shown). The computing device 120 is also configured to detect occlusions in the system 100, as will be described in more detail below. While the illustrated embodiment shows one computing device 120, it should be appreciated that the configuration of the computing device 120 can be implemented in other embodiments as a distributed system with one or more computing devices.

[0022] When the positive displacement pump 116 is operational (e.g., when powered on), irrigation fluid is aspirated from the irrigation fluid source 104, forced by the pump 116 through the irrigation line 108, and passed through the handpiece 102 into the eye 10. When the vacuum source 106 is operational (e.g., when the surgeon commands a vacuum via a foot pedal or the like), aspiration fluid is drawn from the eye 10 through the handpiece 102 and flows through the aspiration line 110 toward a drainage cassette (not shown). If an occlusion occurs in the handpiece 102 (e.g., the tip of the needle 112 is blocked by a substance), fluid cannot flow through the aspiration line 108 and out of the eye 10. The resulting increase in irrigation pressure is sensed by transducer 118 and detected by processor 120, decreasing the flow rate within the irrigation subsystem, which in turn decreases the rotational speed of roller 117 of peristaltic pump 116 to maintain the irrigation pressure of the fluid in irrigation line 108 at a set pressure (e.g., the pressure measured by pressure transducer 118). During operation of system 100, computing device 120 is configured to monitor and calculate the perfusion flow rate based on the pressure and pump speed. After the perfusion flow rate is calculated, computing device 120 is configured to compare the flow rate with a threshold level (e.g., a predefined flow rate, a level slightly higher than the pre-set flow rate, etc.). In cases other than peristaltic pumps, of which positive displacement pumps are exemplified, the pump speed can be a speed similar to the rotational speed of the rollers, such as the rotational speed of a scroll pump, vane pump, or lobe pump, or the reciprocating speed of a piston or plunger in a linear pump.

[0023] If the irrigation flow rate falls below a threshold level and a vacuum is commanded by the processor 120, the handpiece 102, and more specifically the needle 112, is assumed to be occluded, and an occlusion alert is provided to the surgeon by the computing device 120. The alert may be an audible sound, a synthesized voice, a light, a tactile signal (e.g., vibration), and / or an icon on a display. Furthermore, because the irrigation flow rate temporarily decreases when suction (e.g., vacuum) is no longer commanded, the computing device 120 is configured to provide an occlusion alert only when suction is commanded and the irrigation flow rate falls below a threshold level. This prevents an occlusion alert from being provided in scenarios where the irrigation flow rate is low for other reasons, such as when the system 100 is powered off and a vacuum is not commanded. Based on the occlusion alert, the surgeon can take various actions to mitigate the post-occlusion surge and / or prevent surgical complications resulting from the post-occlusion surge, such as, for example, turning off the handpiece 102, stopping the vibration of the needle 112, and / or stopping the command of a vacuum.

[0024] 2 illustrates an example of a method that may be used to detect an occlusion in system 100 and provide an occlusion warning to a user of system 100. Method 200 is described as being implemented in computing device 120, and more generally, in system 100. However, it should be understood that method 200 may be implemented, at least in part, in other computing devices or systems and is not limited to this configuration of system 100. Accordingly, the methods described herein should not be understood as limited to exemplary method 200.

[0025] Method 200 begins with computing device 120 receiving data from sensors at 202. In particular, computing device 120 receives operational data from pump 116 (e.g., the speed of pump 116, etc.) and pressure readings from pressure transducer 118 (e.g., the pressure in irrigation line 108, etc.). Note that additional data may be received from other sensors and / or inputs, including, but not limited to, data from suction pressure transducer 114, input from a foot pedal (not shown), or other input devices. Computing device 120 may receive data continuously, periodically, and / or intermittently from different components of system 100, depending on the requirements and capabilities of system 100.

[0026] After receiving the operational and pressure data, the computing device 120 calculates 204 the flow rate of saline through the irrigation line 108 based on the operational data of the pump 116 and the pressure readings from the pressure transducer 118. The computing device 120 compares 206 the calculated perfusion flow rate to a threshold value. This comparison indicates whether an occlusion has occurred based on a decrease in flow rate on the perfusion side. If the calculated flow rate meets the threshold value (e.g., if the flow rate is equal to or greater than the threshold value), the computing device 120 continues to monitor for occlusion by repeating steps 202-206 of method 200. The threshold value is set at a sufficiently low flow rate to account for normal fluctuations in flow rate during surgery and minimize false occlusion alerts to the user.

[0027] If the calculated flow rate does not meet the threshold (e.g., the flow rate is below the threshold), this may indicate that system 100 is occluded. In response, computing device 120 determines at 208 whether a vacuum has been commanded on the aspiration side of system 100 (e.g., based on input received from a foot pedal or other input device, such as as part of step 202). In particular, if the perfusion side flow rate is below a threshold level and a vacuum has been commanded on the aspiration side by an operator of system 100 (e.g., a surgeon), this indicates that an occlusion has occurred. In some embodiments, computing device 120 determines at 208 whether a vacuum has been commanded before calculating the flow rate at 204 and / or before comparing the flow rate to the threshold at 206.

[0028] Thus, if the perfusion flow rate drops while a vacuum is commanded (e.g., based on a comparison of the calculated flow rate to a threshold value, etc.), computing device 120 provides an occlusion alert or notification to a user (e.g., a surgeon, etc.) of system 100 at 210. In some embodiments, the occlusion alert is a visual, audible, and / or tactile indicator. After the occlusion alert is provided by computing device 120, the user can take steps to mitigate the post-occlusion surge and / or prevent surgical complications resulting from the post-occlusion surge.

[0029] The exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope to those skilled in the art. Numerous specific details are described, such as examples of specific components, devices, and methods, to provide a thorough understanding of the embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, and that the exemplary embodiments can be embodied in many different forms, none of which should be construed as limiting the scope of the present disclosure. In some exemplary embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0030] The specific dimensions, materials, and / or shapes disclosed herein are exemplary in nature and do not limit the scope of the present disclosure. The disclosure herein of a particular value and range of values ​​for a given parameter does not exclude other values ​​and ranges of values ​​that may be useful in one or more examples disclosed herein. Furthermore, it is contemplated that any two specific values ​​for a particular parameter described herein can define the endpoints of a range of values ​​that may be suitable for that given parameter (i.e., disclosure of a first and a second value for a given parameter can be interpreted as disclosing that any value between the first and second values ​​may also be employed for the given parameter). For example, if parameter X is exemplified herein as having a value A and also as having a value Z, it is contemplated that parameter X may have a range of values ​​from about A to about Z. Similarly, the disclosure of two or more ranges of values ​​for a parameter (whether such ranges are nested, overlapping, or distinct) is contemplated to encompass all possible combinations of the ranges of values ​​that may be claimed using the endpoints of the disclosed ranges. For example, if a parameter X is exemplified herein as having a value in the range of 1 to 10, or 2 to 9, or 3 to 8, it is contemplated that the parameter X may have other ranges of values, including 1 to 9, 1 to 8, 1 to 3, 1 to 2, 2 to 10, 2 to 8, 2 to 3, 3 to 10, and 3 to 9.

[0031] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. As used herein, the singular forms "a," "an," and "the" may be intended to include the plural forms unless the context clearly dictates otherwise. The terms "comprise," "comprising," "containing," and "having" are inclusive and thus specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein should not be construed as necessarily requiring performance in the particular order discussed or illustrated, unless specifically identified as such. It is also understood that additional or alternative steps may be employed.

[0032] When an element or layer is referred to as being "on," "engaged," "connected," or "coupled" to another element or layer, it may be directly on, engaged with, connected, or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," or "directly connected to," or "directly coupled" to another element or layer, there may be no intervening elements or layers present. Other words used to describe relationships between elements should be interpreted similarly (e.g., "between" and "directly between," "adjacent" and "directly adjacent," etc.). As used herein, the terms "and / or" and "at least one" include any and all combinations of one or more of the associated listed items.

[0033] Terms such as "first," "second," and "third" may be used herein to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or section from another region, layer, or section. Terms such as "first," "second," and other numerical terms, when used herein, do not imply an order or sequence unless clearly indicated by context. Thus, a first element, component, region, layer, or section discussed below could be referred to as a second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0034] For ease of description, spatially relative terms such as "inside," "outside," "below," "below," "downward," "above," and the like may be used herein to describe the relationship of one element or feature shown in the figures to another element(s) or feature(s). Spatially relative terms may be intended to encompass various orientations of the device in use or operation in addition to the orientation shown in the figures. For example, if the device in the figures were turned over, elements described as "below" or "below" other elements or features would be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein would be interpreted accordingly.

[0035] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended that the disclosure be exhaustive or limiting of the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, may be interchangeable and used in selected embodiments even if not specifically shown or described. The same may also be modified in various ways. Such variations should not be considered a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. [Explanation of symbols]

[0036] 10 eyes 100 Ophthalmic Surgery System 102 Handpiece 104 Irrigation fluid source 106 Vacuum source 108 Irrigation Line 110 Suction Line 112 Phacoemulsification needle 114 Suction pressure transducer 116 Positive Displacement Pump 118 Pressure Transducer 120 Computing Devices 121 memory

Claims

1. In ophthalmic surgery systems, a processor and a memory coupled to the processor; a handpiece operably connected to said processor; a suction subsystem, a vacuum-based suction pump operably connected to said processor; an aspiration line connected between the handpiece and the vacuum-based aspiration pump; and an aspiration pressure transducer operably coupled to the aspiration line and to the processor for sensing pressure within the aspiration line; a suction subsystem comprising: an irrigation subsystem comprising: a perfusion fluid source having a perfusion fluid; an irrigation line connected to the handpiece and to the irrigation fluid source; a positive displacement pump operably connected to the irrigation line between the irrigation fluid source and the handpiece, the positive displacement pump operably connected to the processor; and an irrigation pressure transducer coupled to the irrigation line for sensing irrigation pressure within the irrigation line, the pressure transducer being operably coupled to the processor; an irrigation subsystem comprising:

1. An ophthalmic surgical system comprising: The memory, when executed by the processor, causes the processor to: determining a flow rate of the irrigation fluid through the irrigation line based on at least a rotational speed of the positive displacement pump and a pressure sensed by the pressure transducer; determining whether a vacuum is being commanded by the vacuum-based suction pump; Providing a blockage warning to the user when the irrigation flow rate falls below a threshold level and the vacuum is commanded Contains executable instructions for performing operations; system.

2. 10. The system of claim 1, further comprising a foot pedal operably coupled to the processor, the memory further comprising executable instructions that, when executed by the processor, provide an occlusion warning to the processor if the infusion flow rate falls below the threshold level and the foot pedal is commanding a vacuum to the vacuum-based aspiration pump via the processor.

3. The system of claim 1 , wherein the positive displacement pump is a peristaltic pump.

4. 1. A method of providing occlusion detection in a vacuum-based ophthalmic surgical system, comprising: receiving, by a computing device, operational data from an irrigation transducer positive displacement pump and pressure data from an irrigation transducer, both operably coupled to an irrigation line connecting the handpiece to an irrigation fluid source; determining, by the computing device, whether a vacuum is being commanded to a vacuum-based aspiration pump coupled to the handpiece; calculating, by the computing device, a flow rate of the irrigation fluid through the irrigation line based on the operational data and the pressure data; comparing, by the computing device, the calculated flow rate to a threshold value; and providing, by the computing device, an occlusion warning to a user if the flow rate does not meet the threshold and the vacuum is commanded. A method comprising:

5. The method of claim 4 , wherein the operational data includes a rotational speed of the positive displacement pump.

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