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What to do if…
you notice sudden vision changes like flashing lights, blind spots, or blurred vision

Produced and maintained by PanicStation.org Published: Last reviewed: Editorial policy UK guide

Short answer

Treat new or sudden vision changes as urgent. If you suddenly cannot see from one or both eyes, have sudden severe eye pain, or think it could be a stroke, call 999 or go to A&E; do not drive yourself.

Do not do these things

  • Do not drive yourself to get help or keep going about your day while you “see if it clears”.
  • Do not rub or press on the eye, or keep testing your vision by straining.
  • Do not assume it is “just migraine” if this is new for you, one-sided, or comes with a dark curtain, shadow, or a sudden increase in flashes or floaters.
  • Do not use someone else’s prescription eye drops, especially steroid drops, to see if they help.
  • Do not ignore vision change with face drooping, arm weakness, speech problems, confusion, severe headache, dizziness, or collapse.

What to do now

  1. Go to A&E or call 999 now, and do not drive, if any apply:
    • You suddenly cannot see from one or both eyes, even if it comes and goes.
    • You suddenly have severe eye pain.
    • You have vision change plus possible stroke symptoms, such as face weakness or drooping, arm weakness or numbness, speech problems, confusion, dizziness, falling over, severe headache, or feeling or being sick.
    • You have sudden intense eye pain with a red eye, halos around lights, blurred vision, headache, or feeling or being sick.
  2. If you do not have the emergency signs above, but you have new flashes, new floaters, a new blind spot, a dark curtain or shadow, or new blurred vision, ask for an urgent opticians appointment or get help from NHS 111.
  3. Treat it as especially urgent if the floaters or flashes are happening for the first time, started suddenly, suddenly increased, came with blurred vision or eye pain, or started after eye surgery or an eye injury.
  4. Make a quick one-minute note to take with you or read to the call handler:
    • the time it started
    • which eye is affected, left, right, or both
    • whether it is constant or comes and goes
    • what you noticed, such as flashes, new floaters, blur, blind spot, curtain, shadow, double vision, pain, headache, nausea, or vomiting
    • any recent eye injury, eye surgery, or medication changes
  5. Do one simple safe check only if it does not delay getting help: cover one eye at a time and look at a fixed object to see whether the change is in one eye or both. If symptoms are severe or rapidly worsening, stop checking and focus on urgent help.
  6. Reduce risk while you are getting help: stop driving or cycling, avoid ladders and machinery, and ask someone to stay with you if you feel unsafe or disoriented.
  7. If you wear contact lenses and have redness or pain, remove them only if this is easy and comfortable, keep them out, and tell the optician, NHS 111, or clinician that you were wearing them.
  8. Bring a list of medicines, any eye drops, and your glasses or contact lens details. You may be given pupil-dilating drops, which can cause temporary blur and light sensitivity, so arrange for someone else to help you get home if possible.

What can wait

  • You do not need to decide what the cause is right now.
  • You do not need to search symptoms online or compare stories.
  • You do not need to prove it is serious before seeking urgent help.
  • You can leave work messages, childcare reshuffling, follow-up planning, and longer-term treatment decisions until after you have been assessed or have spoken to NHS 111.

Important reassurance

Sudden vision changes can feel frightening, but asking for urgent help is a reasonable and protective first step. Many causes can be assessed and treated, and quick assessment is the safest way to protect your sight and rule out emergencies.

Scope note

This guide covers first steps only: choosing the right level of urgent care, avoiding common mistakes, and recording key details. Later decisions, tests, treatment, and follow-up may need help from an optician, NHS 111, A&E, an eye specialist, or another qualified professional.

Important note

This is general information, not a diagnosis and not legal, medical, financial, therapeutic, or other professional advice. If you think you may be having an emergency, seek urgent medical help immediately.

Additional Resources

Closely connected guides that may be useful during the same situation or its immediate aftermath.

About this guide

This guide was produced and is maintained by PanicStation.org using its published editorial process. Official and specialist sources are checked where relevant, and AI-assisted tools may be used for drafting, organisation, and consistency checks. The site operator remains responsible for publication, revision, and removal decisions.

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