The study aimed
was to create and confirm a computational model
that describes the deformation characteristics of the corneas mounted in an
artificial anterior chamber in response to an air puff.
2-D (COMSOL Multiphysics model) of an air jet impinging on cornea mounted in an
artificial anterior chamber was created. The CorVis ST, a device that used to
evaluate deformation response in the corneas, was generated the physical air
jet. This air jet was
characterized by hot wire anemometry to obtain spatial flow velocity data.
This hot wire was placed
at the jet exit on the CorVis, and then moved outward with the control to
distances of 3, 6, 9, 12, 15, 20, and 25 mm along the centerline. The
duration of the hot wire anemometry recordings continued 40 ms. Initial data of
the temporal profile shows that the peak velocity along the centerline during
the air puff at distance 0 is over 100 m/s. On the other hand, the peak
velocity reaches above 90 m/s at distances between 9 and 12 mm from nozzle of
the CorVis ST. Accordingly,
the model was set at 100 m/s. The corneal dimensions were modeled by erecting an ellipse
inside an 8mm sphere that was sectioned to have a width of 12 mm. The cornea section was mounted
onto a rigid body into the model, representing the Barron’s Artificial Anterior
Chamber. Intraocular pressure (IOP) was manipulated to be 10, 20, 30,
40, and 50 mmHg. Deformation data from a corneal-scleral rim mounted on an
artificial anterior chamber at these pressures was used to validate the model. At each pressure, the model was
run iteratively to determine the Young’s modulus that required producing
experimentally determined deformations.
result show that the maximum deformation of the model was matched to
experimental deformation data within 0.01% error. The Young’s moduli were 1.569, 1.740, 1.899, 2.099, and
2.250 MPa for pressures at 10, 20, 30, 40, and 50 mmHg, respectively.
The model supports the
relationship between the IOP and the cornea that as IOP increases, the cornea
will become stiffer. Future studies will develop a 3D model as well as modeling
the whole globe.