Construction, calibration and results of a new sensor in an intraocular lens with telemetric transmission of the intraocular pressure

Background: Presently intraocular pressure is measured indirectly by applan ation or impression of the cornea, Only isolated values are available with this method. We present a new implantable system for direct and continuos m easurement of the intraocular pressure. Methods: An implantable system consisting of a miniaturized sensor and a te lemetric unit was integrated in an intraocular lens. The eye pressure is de termined by the sensor, modulated and transduced by the telemetric system. By an extracorporal receiver the signal is demodulated, The electric supply of the intraocular system is achieved by external electromagnetic inductio n. Results: The telemetric transmission of the intraocular pressure can be ach ieved with an accuracy of +/-1 mm Hg and a frequency of registration of 3 v alues per second. Conclusion: Clinical application necessitates further animal trials in vivo .