Low-Profile Induced-Voltage Distance Ranger for Smart Contact Lenses.

Objective We present a novel, low-profile, scleral-coil based, distance ranging system which is suitable for smart, accommodating contact lenses. Methods We measure the induced emf between a set of four thin semi-circular coils patterned on flexible Kapton substrates that conform to the eyes' sclera. This induced emf is a function of eye gaze angles. The distance from the eyes to the desired object is next determined via the triangulation of the eye gaze angles Results: Experiments on simulated tissue gel eyeballs indicate an accurate prediction of object distance in the 0.1-15 D (diopter) range with a 0.15 D RMS error and object direction in the -15 to 15-degree field of view with 0.4-degree RMS error, respectively. The energy required per range reading was determined to be as low as 20 μJ. Conclusion Experimental data shows that the distance ranging system can accurately measure eye-gaze angles and object-distance with very low energy consumption. Significance The high-accuracy, low-profile and reduced energy requirements make the distance ranger suitable for low-power vision corrective applications such as smart contact lenses.