Syringe and cannula for insertion of viscoelastic material into an eye and method of using same

摘要

A syringe for insertion of viscoelastic material into an eye includes a syringe body having an end with an opening therein and a pseudoplastic viscoelastic material disposed in the syringe body. The viscoelastic material is pseudoelastic and may have an initial viscosity of between about 5,000 and about 60,000 centipoise. Correspondingly a cannula is provided which includes a needle having a dispensing orifice on one end thereof and a first portion of between about 23- and about 18-gauge tubing, distal from the dispensing orifice and a second portion of between about 30- and about 23-gauge tubing, proximal to the dispensing orifice. Additionally a housing is provided for attaching another end of the needle, proximal to the first portion, to the end of the syringe body. A method for dispensing the viscoelastic material includes compressing the viscoelastic material in order to force the viscoelastic material out of the syringe and passing the forced viscoelastic material through a large gauge portion of a needle to establish flow of the viscoelastic material. Thereafter the forced viscoelastic material is passed through a narrow gauge portion of the needle for dispensing through an orifice therein.