The study aimedwas to create and validate a computational modelthat describes the deformation characteristics of the corneas mounted in anartificial anterior chamber in response to an air puff. A2-D (COMSOL Multiphysics model) of an air jet impinging on cornea mounted in anartificial anterior chamber was created. The CorVis ST, a device that usedclinically to evaluate deformation response in the corneas, was generated thephysical air jet.
This air jet was characterized with hot wire anemometry toacquire spatial flow velocity data. The hot wire was placed at the jet exit onthe CorVis, and then moved outward with micrometer control to distances of 3,6, 9, 12, 15, 20, and 25 mm along the centerline. The duration of the hot wireanemometry recordings continued 40 ms. Initial data of the temporal profileshows that the peak velocity along the centerline during the air puff atdistance 0 is over 100 m/s.
On the other hand, the peak velocity reaches above90 m/s at distances between 9 and 12 mm from nozzle of the CorVis ST.Accordingly, the model inlet velocity representing the CorVis ST was set at 100m/s. Corneal dimensions were modeled by constructing an ellipse inside an 8mmsphere that was sectioned to have a width of 12 mm. The cornea section wasmounted onto a rigid body within the model, representing the Barron’sArtificial Anterior Chamber. Intraocular pressure (IOP) was manipulated to be10, 20, 30, 40, and 50 mmHg. Deformation data from a corneal-scleral rimmounted on an artificial anterior chamber at these pressures was used tovalidate the model. The model was run iteratively at each pressure to determinethe Young’s modulus required to produce experimentally determined deformations.
Theresult show that maximum deformation amplitude for the model was matched toexperimental deformation data within 0.01% error. The Young’s moduli were1.569, 1.740, 1.899, 2.099, and 2.
250 MPa for pressures of 10, 20, 30, 40, and50 mmHg, respectively.The model supports therelationship between the IOP and the cornea that as IOP increases, the corneawill become stiffer. Future studies will develop a 3D model as well as modelingthe whole globe.