Normal physiologic nystagmus is obtained by watching moving targets; slow components in direction targets are moving, and fast component move in the opposite direction. Abnormal optokinetic nystagmus can be seen in the following:
1. Aberrant regeneration of third nerve-absent vertical optokinetic nystagmus, normal horizontal optokinetic nystagmus
2. Internuclear palsies-horizontal targets bring out dissociation of ocular response movements
3. Lesions of optic tract, geniculate body, temporal and occipital lobes show no asymmetry of horizontal optokinetic responses
4. Lesions of parietal lobe give asymmetric horizontal optokinetic responses
5. Occipital lobe lesions with homonymous hemianopia and asymmetrical horizontal optokinetic responses suggests a mass lesion extending into parietal lobe rather than a vascular lesion
6. Parinaud syndrome-vertical optokinetic nystagmus with targets moving downward enhances the retraction nystagmus seen on attempted upgaze.
7. Parkinsonism (shaking palsy)-vertical optokinetic nystagmus may be reduced
8. See-saw nystagmus-vertical optokinetic nystagmus may be reduced either upward or downward (see p. 144)
9. Test for malingering in "blind" eye or eyes with normal optokinetic responses
Smith JL. Optokinetic nystagmus: its use in topical neuro-ophthalmologic diagnosis. Springfield, IL: Charles C Thomas, 1963.
Walsh FB, Hoyt WF. Clinical neuro-ophthalmology, 4th ed. Baltimore: Williams & Wilkins, 1985.