An ocular surgical insufflation device

Abstract

The application relates to the field of gas injection devices for medical surgical instruments, in particular to an eye surgery gas injection device. In order to solve the problems that the gas injection amount and speed are difficult to control in the hand injection mode, and the hand tremor directly brings the syringe, so that the needle shakes in the deep layer of the corneal stroma. The following scheme is adopted: a gas injection device outer box; a needle tube fixed on the gas injection device outer box; a piston arranged in the needle tube; a lead screw fixed on the piston, which converts the rotary motion into linear motion; a driving mechanism installed on the gas injection device outer box; a nut in screw transmission with the lead screw, and the rotary motion of the driving mechanism is transmitted to the lead screw, and the piston in the needle tube is uniformly translated. The design effectively solves the problems of limited small bubbles caused by insufficient gas injection amount, and backflow overflow caused by improper gas injection speed in manual gas injection, and can stably maintain the corneal internal pressure.

Description

Technical Field

[0001] This invention relates to the field of air injection devices for medical surgical instruments, and specifically to an air injection device for ocular surgery. Background Technology

[0002] Deep anterior lamellar keratoplasty (DLA) is a partial-thickness corneal transplantation procedure that precisely transplants the diseased or opaque anterior stroma, approximately 90%–95% of the corneal thickness, while preserving the patient's own healthy Descemet's membrane and endothelial cells. The corresponding anterior stroma from the donor cornea is then transplanted and fixed in place. Compared to traditional penetrating keratoplasty, this procedure avoids severe endothelial immune rejection and maintains the integrity and closure of the eye's structures.

[0003] The "large bubble technique" is a classic and core technique used in deep anterior lamellar keratoplasty to separate the corneal stroma and Descemet's membrane. By injecting air or a balanced saline solution into the corneal stroma, fluid pressure creates a large, complete separation bubble, or "large bubble," between the Descemet's membrane and the stroma. This perfectly exposes the Descemet's membrane, creating conditions for safe removal of the anterior stromal lesion. However, this technique is highly dependent on the surgeon's experience and feel. The relative depth of the puncture needle is crucial for successful pneumatic separation, typically requiring the relative depth to be controlled within 5% of the expected depth, equivalent to an accuracy of 30 μm. Too shallow a puncture depth will result in bubble failure, while too deep a puncture depth may lead to perforation, necessitating a change to penetrating keratoplasty.

[0004] After the puncture needle reaches the designated depth, the injection volume and injection rate are the two most critical operational variables determining the successful formation of the ideal bubble. Their common goal is to generate sufficient fluid pressure for blunt dissection, while avoiding excessive pressure that could damage the tissue. Insufficient injection volume will confine the bubble to the area around the needle tip, resulting in an incomplete, localized bubble; excessively slow injection will cause the gas to diffuse along the path of least resistance, preventing the opening of local adhesions and resulting in an incomplete bubble; excessive injection volume and excessively fast injection rates will cause a sharp increase in pressure within the bubble cavity, exceeding the elastic limit of the Descemet's membrane, leading to perforation and rupture of the Descemet's membrane, or retrograde leakage of gas along the needle's puncture path, causing local tissue tearing. In practice, the injection volume and injection rate must be controlled collaboratively, dynamically adjusting them based on visual feedback of bubble diffusion and injection pressure feedback. Therefore, using an automated injection device instead of the traditional manual injection process is more beneficial in ensuring the formation of the ideal bubble during deep anterior lamellar keratoplasty.

[0005] Existing patent application CN118304089A discloses a separator and method of use for deep lamellar keratoplasty, including a syringe tube with connecting needles. These needles include a first needle, a second needle, a third needle, and a fourth needle with different bevels and bending angles. Users can select the appropriate connecting needle according to surgical needs and their preferred tool usage, increasing flexibility in tool selection and use. This reduces the risk of accidental injury to surrounding tissues and ensures a safer and more reliable inflation process.

[0006] In existing research on robotic corneal transplant surgery, a small syringe is typically used as the robot's end effector. It is directly connected to the robot's end effector via a handle, and after the robot completes the deep puncture of the corneal stroma, the gas in the syringe is manually injected into the puncture site. Alternatively, some studies have designed a special syringe with an air tube connected to its end, using an air pump to inject gas.

[0007] However, all of the above-mentioned devices require the user to manually inject gas. This method of injection makes it extremely difficult to control the amount and speed of gas injection. When the hand touches the syringe, the hand tremor is also directly introduced into the syringe, causing the needle to vibrate deep in the corneal stroma, which can easily lead to perforation of the Descemet's membrane. Summary of the Invention

[0008] This invention provides an ocular surgical air injection device, the purpose of which is to achieve quantitative and constant-speed air injection by controlling the lead screw, thereby maintaining stable intracorneal pressure.

[0009] The above objectives are achieved through the following technical solutions:

[0010] An ocular surgical air injection device, comprising:

[0011] Outer box of gas injection device;

[0012] The syringe is fixed to the outer casing of the aforementioned gas injection device;

[0013] The piston is located inside the aforementioned syringe;

[0014] The lead screw, fixed to the piston mentioned above, converts its own rotational motion into linear motion;

[0015] The first limiting structure is provided on the mentioned lead screw to limit the rotation of the mentioned lead screw around its own axis;

[0016] The second limiting structure is fixed on the outer casing of the mentioned gas injection device and cooperates with the mentioned first limiting structure to ensure that the mentioned lead screw can only move along the axial direction of the mentioned needle tube.

[0017] The drive mechanism is mounted on the outer casing of the aforementioned air injection device;

[0018] The lead screw, in conjunction with the lead screw, transmits the rotational motion of the drive mechanism to the lead screw.

[0019] The mentioned needle tube is fixed and connected to the end of the outer casing of the gas injection device away from the needle tube. The mentioned needle tube is bent clockwise relative to the mentioned needle tube. The bending angle of the mentioned needle tube is such that when the outer casing of the gas injection device is axially fed, the axial direction of the needle tube is parallel to the feeding direction of the outer casing of the gas injection device.

[0020] The mentioned syringe and the outer casing of the mentioned gas injection device are detachably connected.

[0021] The aforementioned gas injection device has a mounting groove on the left end of its outer casing. The aforementioned needle is inserted into the mounting groove. A mounting shaft is fixed to the outside of the aforementioned gas injection device outer casing. A pressure plate rotates along the aforementioned mounting shaft to open or close. A torsion spring is mounted on the aforementioned mounting shaft to provide the pressure plate with a force to press the aforementioned needle. Alternatively, one end of a pressure cap is hinged to the outer casing of the gas injection device. The pressure cap can be opened or closed on the outer casing of the gas injection device. When the pressure cap is closed on the outer casing of the gas injection device, it can press the needle, thereby fixing the needle. One end of the pressure plate is hinged to the outer casing of the gas injection device, and the other end of the pressure plate can be snapped onto the pressure cap to close the pressure cap on the outer casing of the gas injection device. Alternatively, the aforementioned needle is connected to the inside of the aforementioned gas injection device outer casing by threads and is fixed by a loosening nut.

[0022] The mentioned drive mechanism includes a frameless motor, the rotor of which is fixed to the outer ring of the mentioned nut, and the stator of which is fixed inside the outer casing of the mentioned air injection device.

[0023] It also includes a wire nut end cap fixed to the outer ring on the right side of the wire nut, an encoder rotor housing fixed to the outer ring on the right end of the wire nut, an encoder rotor fixed inside the right side of the encoder rotor housing, an encoder stator located on the right side of the encoder rotor, and an encoder end cap fixed to the right end of the encoder stator.

[0024] It also includes two second bearings. The wire nut end cover and the encoder rotor seat together form two shoulders as mounting grooves for the first second bearing. The inner ring of the first second bearing is fixed on the wire nut end cover and the encoder rotor seat and located in the mounting groove. The two shoulders axially limit the inner ring of the first second bearing. The outer ring of the first second bearing is fixed to the inside of the air injection device outer box. The left part of the wire nut outer ring is fixed to the second second bearing. A shoulder is provided on the left side of the wire nut outer ring. This shoulder and the inner wall of the air injection device outer box axially limit the second second bearing.

[0025] The mentioned drive mechanism includes a motor and a gear transmission assembly. The mentioned motor is fixed on the outer casing of the mentioned air injection device. A gear is fixedly connected to the output shaft of the mentioned motor and the right end of the mentioned nut. The two mentioned gears mesh with each other.

[0026] It also includes two second bearings. The inner wall of the outer casing of the mentioned air injection device is fixed with a shoulder. The outer rings of the two mentioned second bearings abut against the left and right sides of the mentioned shoulder, respectively. The left end of the outer ring of the nut is fixed with a shoulder. The inner ring of the mentioned second bearing on the left abuts against the shoulder on the left end of the mentioned nut, and the inner ring of the mentioned second bearing on the right abuts against the mentioned gear.

[0027] It can be mounted on the end effector of a multi-degree-of-freedom surgical robot and, in conjunction with an automated control system, enable automated gas injection.

[0028] The beneficial effects of the ocular surgery air injection device of the present invention are as follows:

[0029] The drive mechanism rotates the nut, and with the combined constraints of the first and second limiting structures, the rotational motion of the nut is converted into the linear motion of the lead screw, which in turn pushes the piston inside the syringe to move at a uniform speed, achieving precise control over the injection volume and speed. This design effectively solves the problems of insufficient injection volume leading to localized microbubbles and improper injection speed causing perforation of the Descemet's membrane or retrograde gas leakage during manual injection. It can stably maintain intracorneal pressure, ensuring the formation of extensive and complete separation bubbles between the Descemet's membrane and the stroma, creating ideal conditions for the resection of lesions.

[0030] By integrating the gas injection drive mechanism and needle into the outer casing of the gas injection device, this completely replaces the operation of traditional manual syringes. This avoids the transmission of hand vibrations to the needle, preventing needle jitter deep within the corneal stroma. Compared to existing technologies that rely on manual injection or robotic end-effector-based manual syringes, this device fundamentally eliminates the risk of Descemet's membrane perforation caused by vibrations, reducing the probability of conversion to penetrating keratoplasty during surgery and improving surgical safety.

[0031] The drive mechanism employs either a frameless motor directly driving the nut (Example 1) or a motor combined with a gear transmission assembly driving the nut (Example 2). Combined with the axial limiting and support of the bearing assembly, this achieves a high degree of integration of the drive components. The frameless motor drive scheme is smaller in size, and the integrated encoder provides real-time feedback on the nut's rotational status, further improving inflation accuracy. The gear transmission scheme allows for flexible adjustment of the transmission ratio to adapt to different inflation speed requirements. The overall device has a compact structure and can be directly mounted on the end effector of a multi-degree-of-freedom surgical robot, enabling automated inflation operations after precise corneal stroma puncture, thus enhancing the automation level of the surgery.

[0032] The device employs multiple detachable connection methods, including pressure plate torsion spring clamping, pressure cap buckle locking, or threaded connection with anti-loosening nuts, to achieve rapid assembly and disassembly of the needle tube and the outer casing of the inflation device. This design facilitates independent sterilization of the needle tube postoperatively, or allows for the replacement of different sizes of needle tubes and needles according to surgical needs, meeting the strict aseptic operation standards of ophthalmic surgery while improving the versatility and practicality of the device.

[0033] The needle is bent clockwise relative to the needle tube. The bending angle ensures that the needle axis is parallel to the feed direction of the device when the outer casing of the inflation device is axially fed. This design ensures that the needle punctures the corneal stroma along a preset path without the need for additional adjustments to the device's posture, simplifying the operation of the surgical robot and improving the convenience and precision of the surgical procedure.

[0034] This device integrates visual information from microscopic imaging and B-scan OCT imaging with pressure sensing information to construct a hierarchical intelligent control architecture comprising a perception layer, a decision-making layer, and an execution layer. This forms a dual-closed-loop control system with a primary visual closed loop and an auxiliary pressure safety closed loop. It monitors the bubble expansion state in real time through visual feedback and dynamically adjusts injection parameters based on pressure feedback. Differentiated control strategies are employed at different stages, such as bubble nucleus formation, steady-state expansion, and deceleration bonding. Furthermore, pressure thresholds and emergency interruption mechanisms based on perforation characteristics are implemented to further ensure the safety and effectiveness of the injection process, significantly improving the success rate of ideal bubble formation. Attached Figure Description

[0035] Fig. 1 This image shows a perspective view of the drive mechanism of the ocular surgical air injection device according to Embodiment 1.

[0036] Fig. 2 A cross-sectional view of the driving mechanism of the present invention, as shown in Embodiment 1, is displayed;

[0037] Fig. 3 A perspective view of the driving mechanism of the present invention as in Embodiment 2 is shown;

[0038] Fig. 4 A cross-sectional view of the driving mechanism of the present invention, as shown in Embodiment 2, is displayed.

[0039] In the diagram: 1. Outer casing of the air injection device; 2. Needle tube; 3. Piston; 4. Lead screw; 5. Male shaft; 6. First bearing; 7. Pressure plate; 8. Nut; 9. Nut end cover; 10. Encoder rotor seat; 11. Encoder rotor; 12. Encoder stator; 13. Encoder end cover; 14. Second bearing; 15. Frameless motor rotor; 16. Frameless motor stator; 17. Motor; 18. Gear; 19. Gearbox cover. Detailed Implementation

[0040] An ophthalmic surgical air injection device, such as Figs. 1 to 4As shown, it includes an outer casing 1 for an air injection device and a needle tube 2 fixed to the outer casing 1. A piston 3 is installed inside the needle tube 2, and a lead screw 4 is fixed to the right end of the piston 3.

[0041] To further explain, the lead screw 4 has a cross-section to form a first limiting structure. For example, the cross-section of the lead screw 4 is a D-shaped structure or has a keyway structure. The purpose is to make the first limiting structure cooperate with the second limiting structure so that the lead screw 4 loses the freedom to rotate around its own axis and can only translate along the axis of the needle tube 2.

[0042] When the cross-section of the lead screw 4 is D-shaped: the lead screw 4 has a cylindrical surface with threads, and a flat surface without threads. The rotation of the lead screw 4 can be restricted by a limiting scheme, thereby allowing only the axial feed motion of the lead screw 4.

[0043] Specifically, the second limiting structure includes a male shaft 5 fixed to the outer casing 1 of the air injection device, and a first bearing 6 with its inner ring fixed to the male shaft 5. The outer ring of the first bearing 6 is in contact with the cross-sectional line of the lead screw 4, and the two are subject to rolling friction.

[0044] When the cross-section of the lead screw 4 is generated by a keyway structure, the second limiting structure is a convex key fixed on the outer casing 1 of the air injection device. The convex key is set in the keyway to form a sliding friction pair with the lead screw 4.

[0045] To further explain, the left side of the needle tube 2 is fixed and connected to a needle tip, which is bent clockwise relative to the needle tube 2. The bending angle of the needle tip is 30 degrees. At this time, the needle tip is parallel to the base plane of the outer box 1 of the gas injection device, so that when the outer box 1 of the gas injection device moves along its own base plane, the needle tip moves axially.

[0046] To further explain, the needle tube 2 is detachably connected to the outer casing 1 of the gas injection device. Specifically, the left end of the outer casing of the gas injection device has a mounting groove, into which the needle tube 2 is inserted. A mounting shaft is fixed to the outside of the outer casing 1, and a pressure plate 7 is rotatably connected to the mounting shaft. The pressure plate 7 rotates along the mounting shaft to open or close. A torsion spring is fitted onto the mounting shaft; one end of the torsion spring is fixed to the outer casing 1, and the other end is fixed to the pressure plate 7. The torsion spring provides the pressure plate 7 with force to press against the needle tube 2, thereby achieving closure. Alternatively, a pressure cap can be hinged to the outer casing 1. The pressure cap can be opened or closed on the outer casing 1. When the pressure cap is closed on the outer casing 1, it can press against the needle tube 2, thereby fixing the needle tube 2. One end of the pressure plate 7 is hinged to the outer casing 1, and the other end of the pressure plate 7 can be snapped onto the pressure cap to close the pressure cap on the outer casing 1. Of course, other conventional detachable methods can also be used. For example, pre-tightening schemes include bolt pre-tightening and clamping. A snap-locking scheme is also possible. Alternatively, the needle tube 2 can be threaded into the outer casing 1 of the gas injection device, with the right end of the needle tube 2 resting against the inside of the outer casing 1. Simultaneously, a lock nut can be screwed onto the outside of the needle tube 2, resting against the outer casing 1 of the gas injection device.

[0047] A drive mechanism is installed on the right side of the outer casing 1 of the gas injection device. The drive mechanism is screwed to the lead screw 4 to drive the piston 3 to move horizontally.

[0048] Drive mechanism embodiment 1:

[0049] The drive mechanism includes a nut 8, a nut end cap 9 fixed to the outer right ring of the nut 8, an encoder rotor housing 10 fixed to the outer right ring of the nut 8, an encoder rotor 11 fixed inside the right side of the encoder rotor housing 10, an encoder stator 12 located to the right of the encoder rotor 11, and an encoder end cap 13 fixed to the right end of the encoder stator 12. The encoder end cap 13 is fixed to the outer casing 1 of the air injection device. Further, the right side of the outer casing 1 of the air injection device is hollow, allowing the drive mechanism to be inserted. The nut end cap 9 and the encoder rotor housing 10 together form two shoulders serving as mounting grooves for the first second bearing 14. The inner ring of the second bearing 14 is fixed to the nut end cap 9 and the encoder rotor housing 10, and the two shoulders axially limit the inner ring of the first second bearing 14. The outer ring of the first second bearing 14 is fixed inside the outer casing 1 of the air injection device, and the encoder end cap 13 is fixed to the right end of the outer casing 1 of the air injection device. A second second bearing 14 is fixed to the left side of the outer ring of the nut 8. The outer left side of the nut 8 has a shoulder, which, together with the inner wall of the outer casing 1 of the air injection device, axially limits the second bearing 14 and simultaneously limits the nut 8. The nut 8 is then screwed into the lead screw 4. The encoder end cover 13 has a frameless motor drive wire slot and an encoder signal wire slot, and its hollow interior allows the lead screw 4 to pass through.

[0050] To further explain, a frameless motor rotor 15 is fixed to the outer ring of the nut 8. The frameless motor rotor 15 is located between the shoulder of the nut 8 on the left side of its outer ring and the nut end cap 9. A frameless motor stator 16, sleeved on the frameless motor rotor 15, is fixed inside the outer casing 1 of the air injection device. The frameless motor rotor 15 and the frameless motor stator 16 are coaxially mounted. During driving, the frameless motor rotor 15 can rotate inside the frameless motor stator 16 to drive the coaxial rotation of the nut 8. On the other hand, the frameless motor rotor 15 and the aforementioned encoder rotor 11 together drive the rotation of the nut 8.

[0051] Drive mechanism embodiment 2:

[0052] The drive mechanism includes a screw nut 8 driven by a screw 4, with the screw 4 and screw nut 8 coaxially arranged. A motor 17 is fixed to the outer casing 1 of the air injection device. A gear 18 is fixed to the output shaft of the motor 17 and the right end of the screw nut 8, and the two gears 18 mesh for transmission. Two second bearings 14 are rotatably connected to the screw nut 8. A shoulder is fixed to the inner wall of the outer casing 1 of the air injection device, and the outer rings of the two second bearings 14 abut against the left and right sides of the shoulder, respectively. The inner ring of the second bearing 14 on the left abuts against the shoulder at the left end of the screw nut 8. The inner ring of the second bearing 14 on the right abuts against the gear 18. A gearbox cover 19 is fixed to the right end of the outer casing 1 of the air injection device. The gearbox cover 19 and the second bearing 14 on the right restrict the axial displacement of the gear 18.

[0053] The outer casing 1 of the inflator is mounted on the end of the surgical robot / multi-degree-of-freedom robotic arm as a base structure. The position is adjusted by the surgical robot / multi-degree-of-freedom robotic arm. After the puncture needle reaches the designated position at the depth of the corneal stroma, the automatic quantitative and constant-speed inflator operation is achieved under the guidance of visual and pressure feedback, which improves the success rate of ideal bubble formation and avoids secondary damage to surrounding tissues such as the posterior elastic layer of the cornea.

[0054] This application can also be used in conjunction with automated control systems. For example, to achieve automatic gas injection control for ideal bubble formation, it can integrate visual information such as microscopic images / B-scan OCT images with pressure sensing information. The algorithm can be designed as a hierarchical intelligent control architecture, with the system divided into a perception layer, a decision layer, and an execution layer, forming a dual closed-loop architecture of a main visual closed loop and an auxiliary pressure safety closed loop.

[0055] In the multimodal sensing layer, the microscopic image is a top-down view of the cornea, used to monitor the expansion state of the bubble plane; the B-scanOCT is a cross-sectional view of the cornea, used to monitor the internal state information of the bubble, such as bubble depth and interface adhesion; the pressure sensor measures the real-time pressure within the tissue. After image preprocessing and real-time bubble segmentation, the microscopic image information can be used to calculate geometric parameters such as bubble area, equivalent diameter, and leading edge curvature, as well as dynamic parameters such as area change rate and edge diffusion velocity field; after image preprocessing and multi-interface structure segmentation, the B-scanOCT image information can be used to calculate geometric parameters such as bubble height and remaining stromal layer thickness, as well as dynamic parameters such as depth expansion rate; after filtering and denoising, the high-frequency data acquired by the pressure sensor can be used to extract features such as average pressure, pressure fluctuation amplitude, and pressure rise slope.

[0056] At the decision-making level, the aforementioned visual and pressure information will be integrated to determine the injection pressure and rate. For example, a finite state machine can be used as the intelligent decision-making framework: during the initial injection phase, injection is initiated at a low, constant pressure until visual confirmation of bubble nucleus formation; during the steady-state expansion phase, based on visual feedback, a PID controller is used to control the injection pressure with a set edge expansion speed as the target, while a pressure threshold serves as a hard safety limit and the pressure rise slope is an adaptive limit. An emergency injection interruption is triggered when the pressure exceeds the danger threshold or obvious perforation characteristics are visually detected; during the deceleration and bonding phase, when the bubble approaches the target diameter or depth, a lower pressure, more cautious control mode is switched. At any stage, if abnormal pressure is detected or a perforation risk is visually detected, the gas supply is immediately cut off and an alarm is triggered.

[0057] At the decision-making level, another fast PID controller or feedforward-feedback composite control is used to enable the needle pressure to quickly and accurately track the target pressure. The overall control strategy is a hybrid control system with visual servo as the main controller, finite state machine as the strategy framework, real-time pressure monitoring as hard safety protection, and Kalman filtering for multi-sensor fusion, to achieve safe and accurate gas injection control.

[0058] It should be noted that these embodiments of the control system are not intended as additional limitations on the content of this application. The purpose of providing these embodiments is to make the understanding of the disclosure of this application more thorough and comprehensive, to understand that the use of motor, lead screw or gear transmission in this application has the advantages of easy numerical control, high precision and stable adjustment, and to illustrate that the development direction of this application is promising in practical applications.

Claims

1. An ocular surgical air injection device, characterized in that, include: Outer box of gas injection device; The syringe is fixed to the outer casing of the gas injection device; A piston is disposed inside the syringe. The lead screw is fixed to the piston; A first limiting structure is provided on the lead screw to restrict the lead screw from rotating around its own axis; The second limiting structure is fixed on the outer casing of the gas injection device and cooperates with the first limiting structure to allow the lead screw to translate only along the axial direction of the needle tube. The drive mechanism is mounted on the outer casing of the gas injection device; The lead screw nut, through a helical drive with the lead screw, transmits the rotational motion of the drive mechanism to the lead screw, thereby converting the rotational motion of the lead screw into linear motion.

2. The ophthalmic surgical air injection device according to claim 1, characterized in that, The end of the needle tube away from the outer casing of the gas injection device is fixed and connected to a needle tip. The needle tip is bent clockwise relative to the needle tube. The bending angle of the needle tip is such that when the outer casing of the gas injection device is axially fed, the axial direction of the needle tip is parallel to the feeding direction of the outer casing of the gas injection device.

3. The ophthalmic surgical air injection device according to claim 1, characterized in that, The needle tube is detachably connected to the outer casing of the gas injection device.

4. The ocular surgical air injection device according to claim 3, characterized in that, The outer casing of the gas injection device has a mounting groove on its left end, into which the needle is inserted. A mounting shaft is fixed to the outside of the outer casing of the gas injection device. A pressure plate rotates along the mounting shaft to open or close. A torsion spring is fitted on the mounting shaft to provide the pressure plate with a force to press the needle. Alternatively, one end of a pressure cap is hinged to the outer casing of the gas injection device. The pressure cap can be opened or closed on the outer casing of the gas injection device. When the pressure cap is closed on the outer casing of the gas injection device, it can press the needle, thereby fixing the needle. One end of the pressure plate is hinged to the outer casing of the gas injection device, and the other end of the pressure plate can be snapped onto the pressure cap to close the pressure cap on the outer casing of the gas injection device. Alternatively, the needle is connected to the inside of the outer casing of the gas injection device by a thread and fixed by a loosening nut.

5. The ocular surgical air injection device according to claim 1, characterized in that, The drive mechanism includes a frameless motor, the rotor of which is fixed to the outer ring of the nut, and the stator of which is fixed inside the outer casing of the gas injection device.

6. The ophthalmic surgical air injection device according to claim 5, characterized in that, It also includes a wire nut end cap fixed to the outer ring on the right side of the wire nut, an encoder rotor seat fixed to the outer ring on the right end of the wire nut, an encoder rotor fixed inside the right side of the encoder rotor seat, an encoder stator set on the right side of the encoder rotor, an encoder end cap fixed to the right end of the encoder stator, and the encoder end cap fixed to the outer casing of the air injection device.

7. The ophthalmic surgical air injection device according to claim 6, characterized in that, It also includes two second bearings. The wire nut end cover and the encoder rotor seat together form two shoulders as mounting grooves for the first second bearing. The inner ring of the first second bearing is fixed on the wire nut end cover and the encoder rotor seat and located in the mounting groove. The two shoulders axially limit the inner ring of the first second bearing. The outer ring of the first second bearing is fixed to the inside of the air injection device outer box. The left part of the wire nut outer ring is fixed to the second second bearing. A shoulder is provided on the left side of the wire nut outer ring. This shoulder and the inner wall of the air injection device outer box axially limit the second second bearing.

8. The ophthalmic surgical air injection device according to claim 1, characterized in that, The drive mechanism includes a motor and a gear transmission assembly. The motor is fixed on the outer casing of the air injection device. A gear is fixedly connected to the output shaft of the motor and the right end of the nut, and the two gears mesh with each other.

9. The ophthalmic surgical air injection device according to claim 8, characterized in that, It also includes two second bearings. The inner wall of the outer casing of the air injection device is fixed with a shoulder. The outer rings of the two second bearings abut against the left and right sides of the shoulder, respectively. The left end of the outer ring of the nut is fixed with a shoulder. The inner ring of the second bearing on the left abuts against the shoulder at the left end of the nut, and the inner ring of the second bearing on the right abuts against the gear.

10. The ocular surgical air injection device according to any one of claims 1 to 9, characterized in that, It can be mounted on the end effector of a multi-degree-of-freedom surgical robot and, in conjunction with an automated control system, enable automated gas injection.

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