Gaze disorders: A clinical approach

A single clear binocular vision is made possible by the nature through the oculomotor system along with inputs from the cortical areas as well their descending pathways to the brainstem. Six systems of supranuclear control mechanisms play a crucial role in this regard. These are the saccadic system, the smooth pursuit system, the vestibular system, the optokinetic system, the fixation system, and the vergence system. In gaze disorders, lesions at different levels of the brain spare some of the eye movement systems while affecting others. The resulting pattern of eye movements helps clinicians to localize lesions accurately in the central nervous system. Common lesions causing gaze palsies include cerebral infarcts, demyelinating lesions, multiple sclerosis, tumors, Wernicke's encephalopathy, metabolic disorders, and neurodegenerative disorders such as progressive supranuclear palsy. Evaluation of the different gaze disorders is a bane of most budding neurologists and neurosurgeons. However, a simple and systematic clinical approach to this problem can make their early diagnosis rather easy.