uk Health & medical scares sudden vision loss one eye • curtain-like shadow vision • dark curtain in vision • sudden partial vision loss • sudden blind spot one eye • vision went dark suddenly • flashes and floaters sudden • new floaters with shadow • painless vision loss one eye • sudden eye emergency symptoms • possible retinal detachment • possible eye stroke • transient vision loss episode • amaurosis fugax concern • one eye blurry suddenly • missing side vision suddenly • sudden dim vision one eye • sudden visual field loss

What to do if…
you have sudden loss of vision in one eye or a curtain-like shadow

Short answer

Go to A&E immediately. Call 999 if you suddenly cannot see, you have any stroke-like symptoms, or you cannot get to A&E safely.

Do not do these things

Do not “wait and see” if it clears, even if there’s no pain.
Do not drive yourself to A&E. If you cannot get a safe lift quickly, call 999 for an ambulance.
Do not rub or press on the eye.
Do not take leftover prescription eye drops/medication “just in case” (unless a clinician tells you to).
Do not put contact lenses back in (if you were wearing them, keep them out).
Do not assume it’s “just a migraine” if this is new, one-sided, or includes a curtain-like shadow.

What to do now

If you suddenly cannot see from one eye, or you have any stroke signs, call 999 now.
Say: “Sudden loss of vision in one eye / a curtain-like shadow.”
Stroke signs to mention immediately: face drooping, arm weakness, speech trouble, confusion, severe headache, imbalance.
If you can still see but there’s a curtain-like shadow, get same-day urgent assessment.
Go to A&E / an eye emergency department now. If you’re unsure where to go fastest, call NHS 111 for urgent direction while you arrange transport (do not delay if you’re deteriorating).
If you’re alone: unlock your door, sit somewhere safe, keep your phone with you, and message/call someone nearby to be present if possible (but don’t delay urgent care).
Note the exact time it started (or when you were last seeing normally). If it came and went, note start/stop times.
Write down what you noticed (quick bullets are enough):
- “Curtain/shadow” (which side, moving/spreading or fixed)
- Flashes of light, sudden new floaters, distortion, blurred patches
- Pain (or no pain), redness, recent eye injury, recent eye surgery
- Headache, jaw pain when chewing, scalp tenderness, new weakness/numbness, speech issues
Bring essentials (or have them ready for paramedics):
- A list/photos of medicines (especially blood thinners), allergies, and medical conditions
- Your glasses/contact lens details if you have them
- A contact person who can help communicate if you feel overwhelmed

What can wait

You do not need to figure out the cause before getting help.
You do not need to book a routine GP/optician appointment first—this needs urgent same-day assessment via A&E/eye emergency, or NHS 111 if that’s the quickest way to be directed to urgent eye care.
You do not need to keep testing your vision, search symptoms online, or try home treatments right now.

Important reassurance

Feeling frightened is a normal response. Many causes of sudden one-eye vision changes are time-sensitive, so getting checked quickly is the safest move—even if symptoms partly improve.

Scope note

These are first steps only—focused on urgent safety and getting you to the right care fast. Follow-up treatment and next decisions depend on what clinicians find.

Important note

This guide is general information, not a diagnosis. Sudden vision loss or a curtain-like shadow can be a medical emergency even without pain. If you think you cannot safely get help on your own, call 999.

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What to do if…you have sudden loss of vision in one eye or a curtain-like shadow