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 immediately for sudden severe sight loss or a painful red eye with blurred vision, halos, headache, nausea, or vomiting.
Do not drive yourself if your vision is suddenly affected.
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
Seek urgent, same-day eye care for:
A sudden increase in floaters
New flashing lights
A dark patch or curtain moving across your vision
Sudden or rapidly worsening blurred vision
New loss of part of your visual field
3
Does any of this apply?
Book an appointment
Arrange a routine appointment if you notice gradually worsening blur, difficulty reading, poorer night vision, faded colours, or frequent changes in your glasses prescription.
Also arrange screening if you are overdue, even if you have no symptoms.
Every sign above is quoted from the sofidex article on Diabetes and eye disease. If you are not sure, err upward — it is always reasonable to be checked.