---
title: "Sudden vision loss | Eye Health Guide"
description: "Why sudden vision loss is an emergency, the conditions that can cause it, and the warning signs that mean you must seek immediate care."
url: https://eyehealthguide.org/symptoms/sudden-vision-loss/
source: Eye Health Guide
licence: "General information only. Cite the URL and the named medical reviewer."
---

Symptom

# Sudden vision loss

Medical emergency: seek care now

Medical reviewer [Mr Mohamed Mohyudin](https://eyehealthguide.org/reviewers/mohamed-mohyudin/)· Last recorded site review July 6, 2026

### About this review

This page inherits the site’s previous review record. A separate, current article sign-off has not yet been recorded.

[How review works](https://eyehealthguide.org/reviewers/) · [Official biography & credentials](https://mohamedmohyudin.co.uk/author/mohamed-mohyudin/)

Quick answer

A sudden loss of vision, in one or both eyes, whether partial or complete, is a medical emergency. It can be painless or painful. Do not wait to see if it improves: seek immediate emergency eye care, as prompt treatment offers the best chance of protecting your sight.

## Seek emergency care now if you have

- Sudden loss of vision in one or both eyes
- A dark shadow or curtain spreading across your vision
- Sudden vision loss with weakness, numbness or slurred speech
- Sudden painful vision loss with a red eye, halos or nausea

### On this page ⌄

1. Seek emergency care now if you have
2. Possible causes
3. Frequently asked questions

## Possible causes

Sudden vision loss has several serious causes. Seek emergency care first; these are conditions to understand afterwards.

## Frequently asked questions

### Is sudden vision loss an emergency?

Yes. Any sudden loss of vision, in one or both eyes and whether painful or painless, is a medical emergency that needs immediate care.

### What should I do if I suddenly lose vision?

Seek emergency eye care immediately rather than waiting to see if it improves, as prompt treatment offers the best chance of protecting sight.

### Can sudden vision loss come back?

Some causes, such as migraine aura, recover on their own, but you cannot know the cause without assessment, so sudden vision loss must always be treated as an emergency.

Your next step

## Take this to your appointment

Write down what has changed, when it started, your current medicines and the questions you want answered. Take these to your eye-care appointment.

Sudden loss of sight, severe eye pain or a dark curtain across vision needs immediate assessment. Do not wait to complete a worksheet.

## Sources for this information

These references support the information on this page. Follow the linked source for its full context.

- [NHS - Vision loss](https://www.nhs.uk/conditions/vision-loss/)