In an attempt to integrate the present knowledge concerning nystagmus, Fox suggested the following classification, based on the probable sources of origin:
Nystagmus of vestibular origin Physiologic (induced) Rotational Caloric Pathologic (spontaneous) Labyrinthitis Vestibular nerve irritation
Nystagmus of optic origin Physiologic Optokinetic Pathologic (spontaneous; pendular type) Relating to dim light (acquired) Miners' nystagmus Spasmus nutans Due to impaired vision Congenital ocular defects Disorders of visual acuity and the visual fields
Nystagmus of neuromuscular origin Physiologic Positional ("Endstellungsnystagmus") Pathologic Weakness of extra-ocular muscles
Nystagmus of cerebellar origin Lesions of cerebellum Involvement of cerebellar connections in brain stem
Nystagmus of uncertain origin Toxic states Cerebral lesions Disease of the high cervical portion of the spinal cord Hysterical and voluntary nystagmus
The general appellation, "ocular nystagmus," properly includes the types of nystagmus listed in the second and third divisions of the foregoing classification. Each type is caused by a somewhat different