ABC of gaze and ocular oscillations

Abstract

The chief goal of all eye movements is to maintain the image of an object steady on the retina especially the macula to preserve visual acuity. Gaze palsy refers to lack of the conjugate movements due to a failure of supranuclear control mechanisms. Supranuclear control is maintained by not one, but multiple eye movement systems and gaze mechanisms. Supranuclear gaze palsies can be associated with a myriad of aetiologies-from trauma or metabolic abnormalities to stroke, demyelinating disorders and space occupying lesions like tumours. Culprit lesions may be in frontal motor centres, brainstem gaze centres gaze or interconnecting segments. While the brainstem network for horizontal gaze lies in pons, that for vertical gaze is situated in midbrain. Further, ocular oscillations and nystagmus are abnormal eye movements that disrupt a steady fixation of gaze. It is prudent to be aware of various gaze pathways and their anatomical corelates in order to establish a topographic relationship of clinical findings. A systematic clinical examination may provide deep insights on the patho-physiological mechanisms along with aiding in localizing the lesion accurately. This review deals with systematic clinical approach to various gaze control systems.