Micro coils for an advanced system for measuring intraocular pressure

A miniaturised transponder system consisting of a chip and a micro coil for measuring intraocular pressure continuously is presented. The system will be integrated in the haptic of a soft artificial intraocular lens. Calculations show that the capacitance of the coil influences the DC voltage drop significantly. With respect to a reliable system function a 20 µm thick coil with an outer diameter of 10.3 mm, an inner diameter of 7.7 mm, 16 windings and a gap of 20 µm between the windings was selected. Measurements show a good agreement between calculated and measured values. Wireless pressure measurements were carried out showing a linear behaviour of the output signal with respect to the applied pressure.