The neurology of eye movements
2018 Volume 35 Issue 3 Pages 150-154
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2018 Volume 35 Issue 3 Pages 150-154
The study of eye movements is an important source of useful information for clinical neurologists. Abnormal eye movements in patients with neurological disorders often provide diagnostic clues for us.
Eyes appear to have first evolved in the bursts of evolution known as the Cambrian explosion (about 540 million years ago) after the discovery of eyes in fossils. Since then eyes show a wide range of adaptation and development to meet the requirements of the species.
The concept of binocularity was noted by Aristotle more than 2000 years ago. He believed that the two eyes operated as a unit rather than independently. This concept was confirmed by Ewald Hering in 1868 and is now referred to as Hering's law of equal innervation. This principle is the basis of the neuro–ophthalmology. In 1903 Raymond Dodge classified the eye movements into 5 categories, saccades, smooth pursuit, optokinetic, vestibulo–ocular eye movements and vergence. Later visual fixation to maintain the visual gaze on a single object was added to the classification of eye movement in the primates which have a fovea on each eye.
The modern Neuro–ophthalmology was founded in the United States by Frank B. Walsh in Johns Hopkins and David G. Cogan in Harvard around 1947∼48. In 1969 FB Walsh and WF Hoyt published the 3rd edition of Handbook of Clinical Neuro–ophthalmology. This legacy continued in the form of subsequent editions edited by NR Miller and NJ Newman. On the basis of these great mentors, neuro–ophthalmology flourishes today. We are now working in a new era when scientific approaches such as genetics, molecular biology will shift the paradigm from phenomenology to hypothesis proving.
Many abnormal eye movements are distinctive and point to a specific pathophysiology and anatomical localization. In this lecture a series of video–clip will be shown for audience to illustrate clinical and basic points of the patients with eye movement disorders, hoping these clinical and scientific information useful for their clinical diagnosis of various neurological diseases.
