A system includes a processor and a display. The processor is configured to: (a) receive, from a camera inserted into an eye of a patient, at least an optical image of at least a region-of-interest (ROI) of the eye, (b) receive, from a position tracking system (PTS), a position signal indicative of a position of a medical instrument treating the eye, (c) register the optical image and the PTS in a common coordinate system, and (d) estimate the position of the medical instrument in the optical image. The display is configured to visualize at least the ROI and the medical instrument.