A method of tracking an eye of a user on a wearable heads-up display (WHUD) worn on the head of the user includes generating infrared light over an eye tracking period, scanning the infrared light over the eye, and detecting reflections of the infrared light from the eye. A motion parameter that is sensitive to motion of the WHUD is measured. Eye tracking is performed in a first mode that is based on glint for values of the motion parameter that fall within a first range of motion parameter values for which an error in measurement of glint position. Eye tracking is performed in a second mode that is based on glint-pupil vector for values of the motion parameter that fall within a second range of motion parameter values for which an error in measurement of glint position exceeds the error threshold. A head-mounted apparatus with eye tracking is disclosed.