Purpose:
Control of intraocular pressure fluctuation is of critical importance in glaucomatous patients. We present the first measurements using a novel and minimally invasive method to monitor relative intraocular pressure (IOP) changes in the human eye in-vivo by a wireless sensing soft contact lens.
Methods:
The principle of measurement is based on the tiny changes in corneo-scleral curvature induced by variations in IOP. The measurement is performed by a soft silicone Contact Lens Sensor (CLS) with an embedded strain gauge, antenna and microchip. It allows wireless monitoring of IOP changes via an external antenna. The CLS was tested on five healthy volunteers. An increase of IOP was induced by applying a local depressurization during 10 minutes with a scuba mask. Measurements of the ocular pulsation were also recorded.
Results:
The CLS was perfectly tolerated and a slit-lamp exam after the measurement was normal. The filtered CLS signal is well correlated in time and amplitude with the IOP changes measured by Goldmann tonometry during the recovery phase following the depressurization. The ocular pulsation is well demonstrated and comparable to the signal obtained by a Dynamic Contour Tonometer.
Conclusions:
This is the first report of an in-vivo wireless continuous monitoring of the corneo-scleral deformation induced by the IOP changes and ocular pulsation on five human volunteers. Further clinical tests are ongoing to characterize the dependence of the CLS signal amplitude on biometric and biomechanical eye properties. This device potentially allows minimally invasive continuous measurement of relative changes in IOP, during prolonged periods, regardless of patient activity. It can thus, for example, replace the 24-hour IOP curve.
Keywords: intraocular pressure • contact lens