An eyelid position sensor system for an ophthalmic lens comprising anelectronicsystem is described herein for determining at least one of drowsiness or sleeponset ofthe wearer. The eyelid position sensor system is part of an electronic systemincorporated into the ophthalmic lens. The electronic system in at least oneembodiment includes a power source, power management circuitry, one or moresensors, clock generation circuitry, control algorithms and circuitry, and analertmechanism. The eyelid position sensor system is utilized to determine eyelidpositionand use this information to determine if the wearer is asleep or awake.
