Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
1
Is any of this happening now?
Call 911
Seek emergency care if sudden nystagmus occurs with:
Facial drooping, arm or leg weakness, or speech difficulty
Severe trouble walking, collapse, or loss of coordination
Sudden double vision or loss of vision
A new, severe headache
Confusion, fainting, or repeated vomiting
A significant head injury
These combinations can occur with stroke, serious injury, or another acute neurological problem.
Other emergency signs, for anyone
Someone who is struggling to breathe, gasping, choking, or cannot get words out
Someone who has chest pain, tightness or pressure lasting more than a few minutes
Someone who has sudden weakness or drooping on one side of the face or body, slurred speech, or sudden confusion
Someone who is unconscious, or cannot be woken
Someone who is bleeding heavily and it will not stop with firm pressure
Someone who has had a seizure that will not stop, or does not wake up afterwards
Someone who has lips or skin that look pale, blue, grey or blotchy
Someone who you believe has taken an overdose or swallowed something poisonous
2
Is any of this happening?
Be seen today
Babies and children should be assessed promptly because vision is still developing and an underlying eye condition may need treatment.
Seek urgent medical advice for newly developed nystagmus, new oscillopsia, worsening balance, or a clear change in an established eye-movement pattern.
If symptoms began after starting or changing a medicine, contact the prescribing service promptly.
Do not stop the medicine abruptly unless instructed.
Sudden neurological symptoms should not wait for a routine eye appointment.
3
Does any of this apply?
Book an appointment
Arrange a routine eye assessment if you notice repeated eye movements, even when they are painless.
Every sign above is quoted from the sofidex article on Nystagmus. If you are not sure, err upward — it is always reasonable to be checked.