An ophthalmic device arranged as a contact lens (100, 140, 202) comprising: a lens forming a sealed enclosure; an oscillator circuit including a first electrode portion and a second electrode portion, the oscillator circuit disposed within the sealed enclosure of the lens; a driver circuit disposed within the sealed enclosure, the driver circuit coupled to drive the oscillator circuit with a signal to cause the first electrode portion and the second electrode portion to emit an electromagnetic field that extends from the lens, wherein the oscillator circuit is configured to exhibit one or more signal characteristics indicative of an amount of eyelid overlap based at least in part on an electromagnetic interaction between the oscillator circuit and a tear film on the lens, and additionally between the oscillator circuit and a portion of an eyelid that overlaps the oscillator circuit if a portion of the eyelid overlaps the oscillator circuit; an oscillation detector circuit disposed within the sealed enclosure, the oscillation detector circuit coupled to the oscillator circuit to monitor the oscillator circuit for a threshold state of oscillation; and an evaluation circuit disposed within the sealed enclosure, the evaluation circuit coupled to the oscillation detector circuit to receive an indication of the threshold state of oscillation and to correlate the indication of the threshold state of oscillation with an amount of eyelid overlap; wherein the driver circuit includes: initialization circuitry coupled to successively configure multiple initialization states of the oscillator circuit; and a pulse generator coupled to the oscillator circuit, wherein, for each of the multiple initialization states, the pulse generator is configured to provide a respective perturbation of the initialization state, wherein the oscillation detector circuit to monitor the oscillator circuit for the threshold state of oscillation includes an oscillation detector circuit to detect for an oscillation response to the respective perturbation. a lens forming a sealed enclosure; an oscillator circuit including a first electrode portion and a second electrode portion, the oscillator circuit disposed within the sealed enclosure of the lens; a driver circuit disposed within the sealed enclosure, the driver circuit coupled to drive the oscillator circuit with a signal to cause the first electrode portion and the second electrode portion to emit an electromagnetic field that extends from the lens, wherein the oscillator circuit is configured to exhibit one or more signal characteristics indicative of an amount of eyelid overlap based at least in part on an electromagnetic interaction between the oscillator circuit and a tear film on the lens, and additionally between the oscillator circuit and a portion of an eyelid that overlaps the oscillator circuit if a portion of the eyelid overlaps the oscillator circuit; an oscillation detector circuit disposed within the sealed enclosure, the oscillation detector circuit coupled to the oscillator circuit to monitor the oscillator circuit for a threshold state of oscillation; and an evaluation circuit disposed within the sealed enclosure, the evaluation circuit coupled to the oscillation detector circuit to receive an indication of the threshold state of oscillation and to correlate the indication of the threshold state of oscillation with an amount of eyelid overlap; wherein the driver circuit includes: initialization circuitry coupled to successively configure multiple initialization states of the oscillator circuit; and a pulse generator coupled to the oscillator circuit, wherein, for each of the multiple initialization states, the pulse generator is configured to provide a respective perturbation of the initialization state, wherein the oscillation detector circuit to monitor the oscillator circuit for the threshold state of oscillation includes an oscillation detector circuit to detect for an oscillation response to the respective perturbation. initialization circuitry coupled to successively configure multiple initialization states of the oscillator circuit; and a pulse generator coupled to the oscillator circuit, wherein, for each of the multiple initialization states, the pulse generator is configured to provide a respective perturbation of the initialization state, wherein the oscillation detector circuit to monitor the oscillator circuit for the threshold state of oscillation includes an oscillation detector circuit to detect for an oscillation response to the respective perturbation.