Purpose:
Femtosecond lasers can be used to create partial thickness drainage channels in the translucent sclera. These channels can increase the outflow of the aqueous humor therefore have potential for the treatment of glaucoma [1]. We present 3D finite element modeling of the effect of femtosecond laser created partial thickness scleral channels on the reduction of the intraocular pressure IOP.
Methods:
The intact eye was modeled with axial symmetry and developed to a 3D model using COMSOL (COMSOL Inc, MA) finite element software. Partial thickness channels were introduced to the aqueous humor pathway by inputting different values of permeability. To validate the model partial thickness channels were created in cadaver rabbit eye with femtosecond laser tuned to 1.7 µm. The outflow rate was measured by the perfusion method before and after the laser treatment.
Results:
Fig.1 indicates that the channel increased the outflow rate. Fig 2 displays the aqueous humor outflow rate in a treated eye as predicted by the model. It is well visible on the figure that the channel has increased the outflow rate of the aqueous humor. Fitting model parameters to the experimental data sufficient agreement was achieved in between results provided by the model and experiments.
Conclusions:
3D finite element model of the aqueous outflow humor can predict the IOP reduction by the femtosecond laser created partial thickness scleral channels. After sufficient refining 3D finite element modeling may be used for designing the size and the geometry of the partial thickness drainage channels in the sclera for femtosecond laser glaucoma treatments.[1] Juhasz T, "The effect of femtosecond laser scleral treatments on the outflow of aqueous humor," INVEST OPHTHALMOLOGY & VISUAL SCIENCE 45: U392-U392 1052 Suppl. 1, APR 2004.
Keywords: intraocular pressure • aqueous • trabecular meshwork