Abstract:When in designing the non-contact tonometer provides the basis of the numerical analysis in the design structure and size of the nozzle, A numerical model of Non-contact tonometer nozzle using multi-physics coupling analysis software COMSOL Multiphysics was established. And analysising the parameter design of non-contact tonometer nozzle, Which can optimize the size of the nozzle by changing the radii and length. The distribution of pressure and velocity at a rated distance was studied when the nozzle spray cornea at a certain plane. The simulation results show that the optimum of the non-contact tonometer nozzle is located at radius of 1 mm, and 20 mm in length, the rated distance from the nozzle is 10.5mm. The experimental results show that at this condition the nozzle of the Non-contact tonometer can provides an appropriate jet pressure range for the intraocular pressure measurement when the spraying air flow deform the cornea to a certain diameter plane.