Congenital ocular motor apraxia

Congenital ocular motor apraxia, described in 1952 by Professor David Cogan, is characterized by defective or absent voluntary and optically induced horizontal saccades and compensatory jerky head movements or thrusts to accomplish ocular refixation (1-3). The most common initial sign is the inability to follow objects visually. The diagnosis is usually made between the fourth and eighth months of life, with the development of the head thrusts. Children with inadequate cephalic control may never develop the thrusts. When a visual stimulus is presented in the lateral peripheral field of view, an initial head thrust towards the stimulus and overshooting it occur. Both eyes move simultaneously in the opposite direction, responding to the active vestibulo-ocular system. While maintaining fixation, the head slowly moves back until the eyes are straight forward. The eyelids blink at the onset of the head movement to lower the gain of the vestibulo-ocular reflex and thus the amount of the head thrust. The disEuropean Journal of Ophthalmology / Vol. 18 no. 2, 2008 / pp. 282-284