N y s t a g m u s

. Detected during eye movement examination . binocular 1. gaze evoked      nystagmus 2. gaze paretic      nystagmus 3. physiologic      (end gaze)     nystagmus 4. convergence     retraction . . uniocular internuclear ophthalmoplegia .

. Manifest in primary  position . binocular Can the patient see? . . uniocular uniocular image deprivation for example cataract

. Detected by cover test latent nystagmus

Yes with normal vision            Ask patient to fixate distant target . Horizontal or rotatory Describe the waveform, rate and direction . Special pattern upbeat downbeat seesaw .

No or poor vision image deprivation eg. albinism, cataract, aniridia

Ask about the presence of oscillopsia or vertigo .

No Probably congenital  Look for the presence of: 1. head posture 2. same pattern in each position/null position 3. damping by convergence 4. head oscillation 5. optokinetic nystagmus reversal

Yes    Acquired lesion in the  mid-brain or cerebellum

No Observe the movement for a few minutes . non-specific pattern considered drugs, toxins and CNS lesions periodic alternating nystagmus

If the above were present, the patient has congenital nystagmus

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