Eye-tracking systems of the present disclosure may include at least one light source configured to emit radiation toward a location intended for an eye of a user and at least one optical sensor comprising at least one sensing element configured to detect at least a portion of the radiation emitted by the at least one light source. The at least one sensing element may have a lateral width of at least about 5 μm and a lateral length of at least about 5 μm. The eye-tracking system may be configured to track the user's eye using data generated by at least the optical sensor. Various other methods, systems, and devices are also disclosed.