Nystagmus is an involuntary twitching of the eyes in various diseases of the human visual system. One type of nystagmus - fixation - is manifested by involuntary movement of the eye in the direction of the light beam. Diagnosed by the state of the pupil and the characteristics of the reflex action. If it occurs regularly and without treatment, it can change the nature of vision, causing a lot of inconvenience to the patient: it is impossible to read books and look to the side, it is difficult to navigate in space and work at the computer. Treatment of the disease is possible, the main thing is to find out the cause. Conservative therapy, special exercises and massage often help. It is important to identify the type of disease and eliminate danger to the optic nerve.