Techniques and mechanisms for sensing an overlap of an ophthalmic device by an eyelid of a user while the ophthalmic device is disposed in or on an eye of the user. In an embodiment, a circuit, disposed in a sealed enclosure of the ophthalmic device, interacts via an electromagnetic field with a film of tear fluid that is formed on the ophthalmic device. Based on the electromagnetic interaction, an oscillation characteristic of the circuit is evaluated. The oscillation characteristic varies with a resistance that is due in part to an eyelid of the user overlapping at least some portion of the ophthalmic device. Based on the evaluated oscillation characteristic, an amount of the eyelid overlap is determined by circuitry of the ophthalmic device. In another embodiment, the amount of eyelid overlap is used to determine one or more characteristics of gazing by the user's eye.
