Aspects of the present disclosure describe an improved calibration method for systems, methods, and structures that provide eye-tracking by 1) steering a beam of light through the effect of a microelectromechanical system (MEMS) onto a surface of the eye and 2) detecting light reflected from features of the eye including corneal surface, pupil, iris—among others. Positional/geometric/feature/structural information pertaining to the eye is determined from timing information associated with the reflected light.