Ophthalmic needles. An engineering analysis.
Mechanical engineering formulas to predict the amount of flex and the bend strength expected for surgical needles are presented. Bend strength measurements were made on ophthalmic needles produced from two different materials and several shapes. The agreement between the data derived by measurement and the theoretical predictions is excellent. The force required to penetrate porcine corneas is also measured. A needle strength/penetration force ratio was developed from the data presented in this paper. This ratio reveals that needles produced from smaller wire sizes, if optimally designed, can perform as well as existing larger needles.
D000818:Animals; D003315:Cornea / Q000601:surgery; D004738:Engineering; D004867:Equipment Design; D008962:Models, Theoretical; D009339:Needles; D009885:Ophthalmology / Q000295:instrumentation*; D013536:Suture Techniques / Q000295:instrumentation*; D013552:Swine