[Incomitance patterns in different ocular motility disorders]

By measuring the angles stepwise through the whole field of gaze or through selected meridians the pattern of incomitance can be analyzed. It can be graphically demonstrated by "incomitance curves" or "-lines". A preliminary but very useful guess of the incomitance pattern can be obtained in performing the cover test turning the head of the patient passively in small steps. The Hess-Screen gives a quick and useful graphical overview. Synoptometer and Harms tangent screen allow a detailed study. The evaluation of the incomitance pattern allows conclusions on the etiology and explains the remaining binocular field and the head position. In neurogenic palsies, the angle increases in a linear fashion, whereas in passive motor disturbances the angle may increase sharply, change its direction in the opposite direction of gaze and show a zone of concomitance. Duanes retraction syndrome shows passive components. Examples of patients with specific incomitance patterns are shown.