负压吸附式角膜夹持器设计与吸附参数仿真研究

Objective: To propose a scheme to suture the cornea after sucking and raising the cornea to a height suitable for suturing by negative pressure, and conduct the simulation study on suction parameters. Methods: According to surgical requirements, the corneal holder based on negative pressure suction was designed. The simulation models of sucking cornea with straight wound (different types of length, depth and position) were established, and then the procedure of sucking cornea under 6 negative pressure conditions was simulated by fluid-structure interaction to solve the deformation, corneal stress and suction force. The suction force caused by the holder under 6 negative pressure conditions was measured on the PDMS film and compared with the simulation results. The operating safety of the proposed holder was evaluated by in vitro porcine eye experiment. Results: The maximum corneal deformation in all simulation models under negative pressure from -70 kPa to -40 kPa was greater than the maximum raising height of wound required for corneal suturing depth. The maximum corneal deformation increased with the negative pressure decreasing. The maximum corneal stress of all simulation models was less than the corneal stroma damage strength (5 MPa). The suction force of simulation was in good agreement with the experimental results. No corneal rupture occurred when the holder conducted the sucking operation under negative pressure higher than -70 kPa. Conclusions: The corneal holder proposed in this study can meet the required depth in corneal suture surgery within the set negative pressure from -70 kPa to -40 kPa, and can precisely control the suturing depth by changing the negative pressure. The corneal tissues will not be damaged under negative pressure higher than -70 kPa. With the assistance of the corneal holder, doctors can use a straight needle to conduct corneal suture surgery and reduce the difficulty of clinical operations.