Fig. 3

Measuring profile of the contact lens sensor in the water bath in order to investigate possible electromagnetic influences from activated devices (cordless telephone 58 min active, green arrows, smartphone 47 min active, yellow arrows, laptop with wireless internet connection 45 min active, grey arrows). The profile is completely flat and not influenced by these devices. The fluctuations between the measurements lie between the minimum of 1.9 mV eq at 3:28 h and the maximum of 9.8 mV eq at 11:48 h (7.9 mV eq difference, noise). Only by a change of the room temperature (a decrease of 5° Celsius), there is a drop in the profile (red arrow, difference 19.2 mV eq). X-axis time, Y-axis from − 15 to 20 mV eq.