US Patent 11853473 Differential illumination for corneal glint detection

An apparatus, system, and method for detecting glints includes a pair of light sources positioned on a head-mounted frame and driven to illuminate a corneal surface of an eye with differential light signals. An image sensor is positioned on the head-mounted frame to receive reflections of the differential light signals from the corneal surface. An orientation of a cornea (e.g., corneal sphere) of the eye may be determined at least partially based on the reflections of the differential light signals.