Electromagnetic Interaction between Active Ocular Implant for Glaucoma and Adjacent Tissue

FEDERICO SCHAUMBURG; FABIO A GUARNIERI; MARIA CECILIA PEREZ

Orlando

Congreso; ARVO Meeting; 2014

the association for research in vision and ophthalmology

Argentina; CIMEC, CONICET, Santa Fe, Argentina. Purpose: To assess the effect of the electromagnetic field required to power an implantable active drainage device (iMvalv) for the treatment of glaucoma in ocular tissue. Methods: Three different scenarios were simulated using the Finite Element Method: (1) implanted subject exposed to the electromagnetic field source, (2) non-implanted subject exposed to the electromagnetic field source, and (3) unexposed subject (basal state). Distribution of the Specific Absorption Rate (SAR) and temperature increase ( ΔT) were obtained for each scenario. SAR and ΔT maximum values are compared with those recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) not to be exceeded: SARmax = 2W/kg, ΔTmax = 1°C. Simulation results are compared against experimental data obtained by implanting five rabbits with iMvalv prototypes, according with the statment for the use of animals in vision and ophthalmic research. Results: For the implanted subject, steady-state maximum values at the working frequency and power were: SAR = 14 mW/kg and ΔT = 0.08 °C. Dynamic studies showed that steady-state values were not exceeded. Perceptual difference between implanted and non- implanted subjects is 5.4% for ΔT and 0.4% for SAR. Conclusions: Maximum values obtained, were far from those recommended by ICNIRP not to be exceeded. The main mechanism causing temperature increase and electromagnetic energy absorption was found to be the EMF source itself, being the effects of the implant, negligible.