Force modeling for needle insertion into corneal tissue

The mechanical behavior of needle puncturing corneal tissue was analyzed, and the interactive forces between the needle and corneal tissue were resolved into three components, the surface contact force, the friction force and the cutting force. Then a sine loading testing was done based on the modified Karnopp friction model. With the relationship between friction and time, a friction model was established. Then the contact force model was obtained by the quadratic curve fitting from the testing results of surface contact force during needle puncturing tissue. Finally, the cutting force model was concluded according to the testing curve and the friction force model. The research results can be used in fine manipulation during corneal-grafting surgery.