A method that includes illuminating an eye with light at a first time and a second time and generating a first image of the eye based on the light that illuminates the eye at the first time. The method includes generating a second image of the eye based on the light that illuminates the eye at the second time. The method further includes positioning a laser source relative to the eye, wherein the laser source generates a therapeutic laser beam to be directed to the eye, wherein the first time is just prior to the therapeutic laser beam being directed to the eye and the second time is prior to the first time. The method further includes correcting orientation of the laser source relative to the eye based on a correlation function that is defined for the first and second images of the eye.