Abstract: A disclosed apparatus may include a line source configured to produce a line of light and a scanning device configured to scan the line of light across a scanning field in a scanning direction. The scanning field may include a receiving portion configured to receive an eye. The apparatus may also include a reflector positioned within the scanning field. During a primary period of a scan, the line of light may scan the receiving portion in a primary direction. During a secondary period of the scan, the reflector may reflect the line of light such that a reflection of the line of light scans the receiving portion in a secondary direction. The apparatus may also include a photodetector positioned to receive (1) an initial reflection during the primary period, and (2) a subsequent reflection during the secondary period. Various other methods, apparatuses, and computer-readable media are also disclosed.