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
Get emergency help for a chemical splash, a penetrating eye injury, or sudden loss of vision.
Rinse a chemical-exposed eye immediately with plenty of clean, lukewarm water while arranging emergency advice.
Do not try to remove an object embedded in the eye.
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 same-day medical care if watering comes with:
Significant eye pain or strong sensitivity to light
A sudden change or reduction in vision
Marked redness, swelling, or pus-like discharge
A painful red eye while wearing contact lenses
Fever or swelling spreading around the eye
A particle that remains trapped after gentle rinsing
3
Does any of this apply?
Book an appointment
For routine care, book an appointment if watering keeps returning, has no clear short-lived trigger, affects reading or driving, or causes repeated soreness or infections.
A baby should be assessed if watering is accompanied by significant redness, swelling, pain, fever, or marked discharge.
The article also says
Stop wearing contact lenses until a painful, red, or unusually watery eye has been assessed.
Every sign above is quoted from the sofidex article on Watering eyes. If you are not sure, err upward — it is always reasonable to be checked.