Electromagnetic Modelling Of A Human Eye Exposed To Conductive Keratoplasty
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This paper presents 3D numerical solutions of the current density, absorbed energy and initial impedance of the human eye exposed to conductive keratoplasty (CK) scenarios obtained with the boundary element method. CK is a non-ablative surgical technique for the treatment of mild to moderate hyperopia (far-sightedness). In a CK session a thin electrode penetrates the cornea delivering pulsed radiofrequency energy at 350 kHz to the surrounding tissue. The electromagnetic (EM) energy is dissipated into heat in the tissue surrounding the tip yielding thermally localised shrinkage and tightening of the collagen llamelae. When applied in a controlled way, this relatively new technique allows eye surgeons to correct the shape of the cornea and to treat common types of eye disease such as far-sightedness or astigmatism. This work examines in detail the induced currents that appear in the rest of the eye while delivering the EM signal. Quantitative estimations of the EM energy absorbed in each tissue per unitary voltage apart from the cornea is presented, as well as the impedance of the electrodes at initial time. Keywords: human eye, conductive keratoplasty, boundary element method, electric field. 1 Introduction There is a great deal of interest in understanding the electrical properties of the human eye in the low frequency (LF) range, and how it behaves as a complex imperfect conductive body. Studies consider the eye as either a passive element exposed to an external field, or as an active one which produces a complicated pattern of electrical signals in response to light. The former is usually tackled in order to understand the vulnerability of the different tissues when exposed to potentially harmful levels of electric fields at different frequencies, orders of magnitude and
human eye, conductive keratoplasty, boundary element method, electric field.